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Importance: Sudden infant death syndrome (SIDS) is a major cause of infant death in the US. Previous research suggests that inborn errors of metabolism may contribute to SIDS, yet the relationship between SIDS and biomarkers of metabolism remains unclear., Objective: To evaluate and model the association between routinely measured newborn metabolic markers and SIDS in combination with established risk factors for SIDS., Design, Setting, and Participants: This was a case-control study nested within a retrospective cohort using data from the California Office of Statewide Health Planning and Development and the California Department of Public Health. The study population included infants born in California between 2005 and 2011 with full metabolic data collected as part of routine newborn screening (NBS). SIDS cases were matched to controls at a ratio of 1:4 by gestational age and birth weight z score. Matched data were split into training (2/3) and testing (1/3) subsets. Data were analyzed from January 2005 to December 2011., Exposures: Metabolites measured by NBS and established risk factors for SIDS., Main Outcomes and Measures: The primary outcome was SIDS. Logistic regression was used to evaluate the association between metabolic markers combined with known risk factors and SIDS., Results: Of 2 276 578 eligible infants, 354 SIDS (0.016%) cases (mean [SD] gestational age, 38.3 [2.3] weeks; 220 male [62.1%]) and 1416 controls (mean [SD] gestational age, 38.3 [2.3] weeks; 723 male [51.1%]) were identified. In multivariable analysis, 14 NBS metabolites were significantly associated with SIDS in a univariate analysis: 17-hydroxyprogesterone, alanine, methionine, proline, tyrosine, valine, free carnitine, acetyl-L-carnitine, malonyl carnitine, glutarylcarnitine, lauroyl-L-carnitine, dodecenoylcarnitine, 3-hydroxytetradecanoylcarnitine, and linoleoylcarnitine. The area under the receiver operating characteristic curve for a 14-marker SIDS model, which included 8 metabolites, was 0.75 (95% CI, 0.72-0.79) in the training set and was 0.70 (95% CI, 0.65-0.76) in the test set. Of 32 infants in the test set with model-predicted probability greater than 0.5, a total of 20 (62.5%) had SIDS. These infants had 14.4 times the odds (95% CI, 6.0-34.5) of having SIDS compared with those with a model-predicted probability less than 0.1., Conclusions and Relevance: Results from this case-control study showed an association between aberrant metabolic analytes at birth and SIDS. These findings suggest that we may be able to identify infants at increased risk for SIDS soon after birth, which could inform further mechanistic research and clinical efforts focused on monitoring and prevention.

Background: African-born women have a lower risk of preterm birth and small for gestational age (SGA) birth compared with United States-born Black women, however variation by country of origin is overlooked. Additionally, the extent that nativity disparities in adverse perinatal outcomes to Black women are explained by individual-level factors remains unclear., Methods: We conducted a population-based study of nonanomalous singleton live births to United States- and African-born Black women in California from 2011 to 2020 (n = 194,320). We used age-adjusted Poisson regression models to estimate the risk of preterm birth and SGA and reported risk ratios (RR) and 95% confidence intervals (CI). Decomposition using Monte Carlo integration of the g-formula computed the percentage of disparities in adverse outcomes between United States- and African-born women explained by individual-level factors., Results: Eritrean women (RR = 0.4; 95% CI = 0.3, 0.5) had the largest differences in risk of preterm birth and Cameroonian women (RR = 0.5; 95% CI = 0.3, 0.6) in SGA birth, compared with United States-born Black women. Ghanaian women had smaller differences in risk of preterm birth (RR = 0.8; 95% CI = 0.7, 1.0) and SGA (RR = 0.9; 95% CI = 0.8, 1.1) compared with United States-born women. Overall, we estimate that absolute differences in socio-demographic and clinical factors contributed to 32% of nativity-based disparities in the risk of preterm birth and 26% of disparities in SGA., Conclusions: We observed heterogeneity in risk of adverse perinatal outcomes for African- compared with United States-born Black women, suggesting that nativity disparities in adverse perinatal outcomes were not fully explained by differences in individual-level factors., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: To describe changes over time in resuscitation, survival, and morbidity of extremely preterm infants in California., Study Design: This population-based, retrospective cohort study includes infants born ≤28 weeks. Linked birth certificates and hospital discharge records were used to evaluate active resuscitation, survival, and morbidity across two epochs (2011-2014, 2015-2019)., Results: Of liveborn infants, 0.6% were born ≤28 weeks. Active resuscitation increased from 16.9% of 22-week infants to 98.1% of 25-week infants and increased over time in 22-, 23-, and 25-week infants (p-value ≤ 0.01). Among resuscitated infants, survival to discharge increased from 33.2% at 22 weeks to 96.1% at 28 weeks. Survival without major morbidity improved over time for 28-week infants (p-value < 0.01)., Conclusion: Among infants ≤28 weeks, resuscitation and survival increased with gestational age and morbidity decreased. Over time, active resuscitation of periviable infants and morbidity-free survival of 28-week infants increased. These trends may inform counseling around extremely preterm birth., (© 2023. The Author(s).)

Objective: To determine the validity of diagnostic hospital billing codes for complications of prematurity in neonates <32 weeks gestation., Study Design: Retrospective cohort data from discharge summaries and clinical notes (n = 160) were reviewed by trained, blinded abstractors for the presence of intraventricular hemorrhage (IVH) grades 3 or 4, periventricular leukomalacia (PVL), necrotizing enterocolitis (NEC), stage 3 or higher, retinopathy of prematurity (ROP), and surgery for NEC or ROP. Data were compared to diagnostic billing codes from the neonatal electronic health record., Results: IVH, PVL, ROP and ROP surgery had strong positive predictive values (PPV > 75%) and excellent negative predictive values (NPV > 95%). The PPVs for NEC (66.7%) and NEC surgery (37.1%) were low., Conclusion: Diagnostic hospital billing codes were observed to be a valid metric to evaluate preterm neonatal morbidities and surgeries except in the instance of more ambiguous diagnoses such as NEC and NEC surgery., (© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Objective: Develop and validate a resiliency score to predict survival and survival without neonatal morbidity in preterm neonates <32 weeks of gestation using machine learning., Study Design: Models using maternal, perinatal, and neonatal variables were developed using LASSO method in a population based Californian administrative dataset. Outcomes were survival and survival without severe neonatal morbidity. Discrimination was assessed in the derivation and an external dataset from a tertiary care center., Results: Discrimination in the internal validation dataset was excellent with a c-statistic of 0.895 (95% CI 0.882-0.908) for survival and 0.867 (95% CI 0.857-0.877) for survival without severe neonatal morbidity, respectively. Discrimination remained high in the external validation dataset (c-statistic 0.817, CI 0.741-0.893 and 0.804, CI 0.770-0.837, respectively)., Conclusion: Our successfully predicts survival and survival without major morbidity in preterm babies born at <32 weeks. This score can be used to adjust for multiple variables across administrative datasets., (© 2022. The Author(s).)

Background and Aims: The American Academy of Pediatrics describes late preterm infants, born at 34 to 36 completed weeks' gestation, as at-risk for rehospitalization and severe morbidity as compared to term infants. While there are prediction models that focus on specific morbidities, there is limited research on risk prediction for early readmission in late preterm infants. The aim of this study is to derive and validate a model to predict 7-day readmission., Methods: This is a population-based retrospective cohort study of liveborn infants in California between January 2007 to December 2011. Birth certificates, maintained by California Vital Statistics, were linked to a hospital discharge, emergency department, and ambulatory surgery records maintained by the California Office of Statewide Health Planning and Development. Random forest and logistic regression were used to identify maternal and infant variables of importance, test for association, and develop and validate a predictive model. The predictive model was evaluated for discrimination and calibration., Results: We restricted the sample to healthy late preterm infants ( n  = 122,014), of which 4.1% were readmitted to hospital within 7-day after birth discharge. The random forest model with 24 variables had better predictive ability than the 8 variable logistic model with c-statistic of 0.644 (95% confidence interval 0.629, 0.659) in the validation data set and Brier score of 0.0408. The eight predictors of importance length of stay, delivery method, parity, gestational age, birthweight, race/ethnicity, phototherapy at birth hospitalization, and pre-existing or gestational diabetes were used to drive individual risk scores. The risk stratification had the ability to identify an estimated 19% of infants at greatest risk of readmission., Conclusions: Our 7-day readmission predictive model had moderate performance in differentiating at risk late preterm infants. Future studies might benefit from inclusion of more variables and focus on hospital practices that minimize risk., Competing Interests: The authors declare no conflict of interest., (© 2023 The Authors. Health Science Reports published by Wiley Periodicals LLC.)

Objectives: To determine whether socioeconomic status (SES) and small birthweight for gestational age (SGA) exhibit independent or joint effects on infant levels of 42 metabolites., Study Design: Population-based retrospective cohort of metabolic newborn screening information linked to hospital discharge data. SGA infants defined by birthweight <10th percentile for gestational age by sex. SES was determined by a combined metric including education level, participation in the WIC nutritional assistance program, and receiving California MediCal insurance. We performed linear regression to determine the effects of SES independently, SGA independently, and the interaction of SGA and SES on 42 newborn metabolite levels., Results: 736,435 California infants born in 2005-2011 were included in the analysis. SGA was significantly associated with 36 metabolites. SES was significantly associated with 41 of 42 metabolites. Thirty-eight metabolites exhibited a dose-response relationship between SGA and metabolite levels as SES worsened. Fourteen metabolites showed significant interaction between SES and SGA. Eight metabolites showed significant individual and joint effects of SES and SGA: alanine, glycine, free carnitine, C-3DC, C-5DC, C-16:1, C-18:1, and C-18:2., Conclusions: SES and SGA exhibited independent effects on a majority of metabolites and joint effects on select metabolites. A better understanding of how SES and SGA status are related to infant metabolites may help identify maternal and newborn interventions that can lead to better outcomes for infants born SGA.

Objective: Evaluate the risk of preterm (<37 weeks) or early term birth (37 or 38 weeks) by body mass index (BMI) in a propensity score-matched sample., Design: Retrospective cohort analysis., Setting: California, USA., Population: Singleton live births from 2011-2017., Methods: Propensity scores were calculated for BMI groups using maternal factors. A referent sample of women with a BMI between 18.5 and <25.0 kg/m 2 was selected using exact propensity score matching. Risk ratios for preterm and early term birth were calculated., Main Outcome Measures: Early birth., Results: Women with a BMI <18.5 kg/m 2 were at elevated risk of birth of 28-31 weeks (relative risk [RR] 1.2, 95% CI 1.1-1.4), 32-36 weeks (RR 1.3, 95% CI 1.2-1.3), and 37 or 38 weeks (RR 1.1, 95% CI 1.1-1.1). Women with BMI ≥25.0 kg/m 2 were at 1.2-1.4-times higher risk of a birth <28 weeks and were at reduced risk of a birth between 32 and 36 weeks (RR 0.8-0.9) and birth during the 37th or 38th week (RR 0.9)., Conclusion: Women with a BMI <18.5 kg/m 2 were at elevated risk of a preterm or early term birth. Women with BMI ≥25.0 kg/m 2 were at elevated risk of a birth <28 weeks. Propensity score-matched women with BMI ≥30.0 kg/m 2 were at decreased risk of a spontaneous preterm birth with intact membranes between 32 and 36 weeks, supporting the complexity of BMI as a risk factor for preterm birth., Tweetable Abstract: Propensity score-matched women with BMI ≥30 kg/m 2 were at decreased risk of a late spontaneous preterm birth., (© 2022 John Wiley & Sons Ltd.)

Objective: Late preterm infants have an increased risk of morbidity relative to term infants. We sought to determine the rate, temporal trend, risk factors, and reasons for 30-day readmission., Methods: This is a retrospective cohort study of infants born at 34 to 42 weeks' gestation in California between January 1, 2011, and December 31, 2017. Birth certificates maintained by California Vital Statistics were linked to discharge records maintained by the California Office of Statewide Health Planning and Development. Multivariable logistic regression was used to identify risk factors and derive a predictive model., Results: Late preterm infants represented 4.3% (n = 122 014) of the study cohort (n = 2 824 963), of which 5.9% (n = 7243) were readmitted within 30 days. Compared to term infants, late preterm infants had greater odds of readmission (odds ratio [OR]: 2.34 [95% confidence interval (CI): 2.28-2.40]). The temporal trend indicated increases in all-cause and jaundice-specific readmission infants (P < .001). The common diagnoses at readmission were jaundice (58.9%), infections (10.8%), and respiratory complications (3.5%). In the adjusted model, factors that were associated with greater odds of readmission included assisted vaginal birth, maternal age ≥34 years, diabetes, chorioamnionitis, and primiparity. The model had predictive ability of 60% (c-statistic 0.603 [95% CI: 0.596-0.610]) in late preterm infants who had <5 days length of stay at birth., Conclusion: The findings contribute important information on what factors increase or decrease the risk of readmission. Longitudinal studies are needed to examine promising hospital predischarge and follow-up care practices., (Copyright © 2022 by the American Academy of Pediatrics.)

Introduction: Previous studies that used traditional multivariable and sibling matched analyses to investigate interpregnancy interval (IPI) and birth outcomes have reached mixed conclusions about a minimum recommended IPI, raising concerns about confounding. Our objective was to isolate the contribution of interpregnancy interval to the risk for adverse birth outcomes using propensity score matching., Methods: For this retrospective cohort study, data were drawn from a California Department of Health Care Access and Information database with linked vital records and hospital discharge records (2007-2012). We compared short IPIs of < 6, 6-11, and 12-17 months to a referent IPI of 18-23 months using 1:1 exact propensity score matching on 13 maternal sociodemographic and clinical factors. We used logistic regression to calculate the odds of preterm birth, early-term birth, and small for gestational age (SGA)., Results: Of 144,733 women, 73.6% had IPIs < 18 months, 5.5% delivered preterm, 27.0% delivered early-term, and 6.0% had SGA infants. In the propensity matched sample (n = 83,788), odds of preterm birth were increased among women with IPI < 6 and 6-11 months (OR 1.89, 95% CI 1.71-2.0; OR 1.22, 95% CI 1.13-1.31, respectively) and not with IPI 12-17 months (OR 1.01, 95% CI 0.94-1.09); a similar pattern emerged for early-term birth. The odds of SGA were slightly elevated only for intervals < 6 months (OR 1.10, 95% CI 1.00-1.20, p < .05)., Discussion: This study demonstrates a dose response association between short IPI and adverse birth outcomes, with no increased risk beyond 12 months. Findings suggest that longer IPI recommendations may be overly proscriptive., (© 2022. The Author(s).)

Background: Birthing people of color are more likely to deliver low birthweight and preterm infants, populations at significant risk of morbidity and mortality. Birthing people of color are also at higher risk for mental health conditions and emergency mental healthcare utilization postpartum. Although this group has been identified as high risk in these contexts, it is not known whether racial and ethnic disparities exist in mental healthcare utilization among birthing people who have delivered preterm., Objective: We sought to determine if racial and ethnic disparities exist in postpartum mental healthcare-associated emergency department visits or hospitalizations for birthing people with preterm infants in a large and diverse population., Study Design: This population-based historic cohort study used a sample of Californian live-born infants born between 2011 and 2017 with linked birth certificates and emergency department visit and hospital admission records from the California Statewide Health Planning and Development database. The sample was restricted to preterm infants (<37 weeks' gestation). Self-reported race and ethnicity groups included Hispanic, non-Hispanic Black, non-Hispanic Asian, non-Hispanic White, and non-Hispanic others. Mental health diagnoses were identified from the International Classification of Diseases Ninth and Tenth revision codes recorded in emergency department and hospital discharge records. Logistic regression analysis was used to estimate the association between mental health-related emergency department visits and rehospitalizations by race or ethnicity compared with non-Hispanic White birthing people and controlling for the following characteristics and health condition covariates: age, parity, previous preterm birth, body mass index, smoking, alcohol use, hypertension, diabetes, previous mental health diagnosis, and prenatal care., Results: Of 204,539 birthing people who delivered preterm infants in California, 1982 visited the emergency department and 836 were hospitalized in the first year after preterm birth for a mental health-related illness. Black birthing people were more likely to have a mental health-related emergency department visit and hospitalization (risk ratio, 1.8; 95% confidence interval, 1.5-2.0 and risk ratio, 1.9; 95% confidence interval, 1.5-2.3, respectively) within the first postpartum year than White birthing people. Hispanic and Asian birthing people were less likely to have mental health-related emergency department visits (adjusted risk ratio, 0.7; 95% confidence interval, 0.7-0.8 and adjusted risk ratio, 0.2; 95% confidence interval, 0.2-0.3, respectively) and hospitalizations (adjusted risk ratio, 0.6; 95% confidence interval, 0.5-0.7 and adjusted risk ratio, 0.2; 95% confidence interval, 0.1-0.3, respectively). When controlling for birthing people with a previous mental health diagnosis and those without, the disparities remained the same., Conclusion: Racial and ethnic disparities exist in emergency mental healthcare escalation among birthing people who have delivered preterm infants. Our findings highlight a need for further investigation into disparate mental health conditions, exacerbations, access to care, and targeted hospital and legislative policies to prevent emergency mental healthcare escalation and reduce disparities., (Published by Elsevier Inc.)

Objective: Our study sought to determine whether metabolites from a retrospective collection of banked cord blood specimens could accurately estimate gestational age and to validate these findings in cord blood samples from Busia, Uganda., Study Design: Forty-seven metabolites were measured by tandem mass spectrometry or enzymatic assays from 942 banked cord blood samples. Multiple linear regression was performed, and the best model was used to predict gestational age, in weeks, for 150 newborns from Busia, Uganda., Results: The model including metabolites and birthweight, predicted the gestational ages within 2 weeks for 76.7% of the Ugandan cohort. Importantly, this model estimated the prevalence of preterm birth <34 weeks closer to the actual prevalence (4.67% and 4.00%, respectively) than a model with only birthweight which overestimates the prevalence by 283%., Conclusion: Models that include cord blood metabolites and birth weight appear to offer improvement in gestational age estimation over birth weight alone., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Newborn metabolic screening is emerging as a novel method for predicting neonatal morbidity and mortality in neonates born very preterm (<32 weeks gestation). The purpose of our study was to determine if blood collected by an electrolyte-balanced dry lithium heparin syringe, as is routine for blood gas measurements, affects targeted metabolite and biomarker levels. Two blood samples (one collected with a heparinized syringe and the other with a non-heparinized syringe) were obtained at the same time from 20 infants with a central arterial line and tested for 49 metabolites and biomarkers using standard procedures for newborn screening. Overall, the median metabolite levels did not significantly differ by syringe type. However, there was wide variability, particularly for amino acids and immunoreactive trypsinogen, for individual paired samples and therefore, consideration should be given to sample collection when using these metabolites in prediction models of neonatal morbidity and mortality., (Copyright © 2021 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Objective: Examine the risk of adverse perinatal outcomes among the United States (US)-born and foreign-born Black women in California., Study Design: The study comprised all singleton live births to Black women in California between 2011 and 2017. We defined maternal nativity as US-born or foreign-born. Using Poisson regression, we computed risk ratios (RR) and 95% confidence intervals (CI) for three adverse perinatal outcomes: preterm birth, small for gestational age deliveries, and infant mortality., Results: Rates of adverse perinatal outcomes were significantly higher among US-born Black women. In adjusted models, US-born Black women experienced an increased risk of preterm birth (RR 1.51, 95% CI 1.39, 1.65) and small for gestational age deliveries (RR 1.52, 95% CI 1.41, 1.64), compared to foreign-born Black women., Conclusions: Future studies should consider experiences of racism across the life course when exploring heterogeneity in the risk of adverse perinatal outcomes by nativity among Black women in the US., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc.)

This project examines risk and protective factors for preterm birth (PTB) among Black women in Oakland, California. Women with singleton births in 2011-2017 (n = 6199) were included. Risk and protective factors for PTB and independent risk groups were identified using logistic regression and recursive partitioning. Having less than 3 prenatal care visits was associated with highest PTB risk. Hypertension (preexisting, gestational), previous PTB, and unknown Women, Infant, Children (WIC) program participation were associated with a two-fold increased risk for PTB. Maternal birth outside of the USA and participation in WIC were protective. Broad differences in rates, risks, and protective factors for PTB were observed., (© 2020. W. Montague Cobb-NMA Health Institute.)

Introduction: Our understanding of the association between coronavirus disease 19 (COVID-19) and preterm or early term birth among racially and ethnically diverse populations and people with chronic medical conditions is limited., Methods: We determined the association between COVID-19 and preterm (PTB) birth among live births documented by California Vital Statistics birth certificates between July 2020 and January 2021 (n=240,147). We used best obstetric estimate of gestational age to classify births as very preterm (VPTB, <32 weeks), PTB (< 37 weeks), early term (37 and 38 weeks), and term (39-44 weeks), as each confer independent risks to infant health and development. Separately, we calculated the joint effects of COVID-19 diagnosis, hypertension, diabetes, and obesity on PTB and VPTB., Findings: COVID-19 diagnoses on birth certificates increased for all racial/ethnic groups between July 2020 and January 2021 and were highest for American Indian/Alaska Native (12.9%), Native Hawaiian/Pacific Islander (11.4%), and Latinx (10.3%) birthing people. COVID-19 diagnosis was associated with an increased risk of VPTB (aRR 1.6, 95% CI [1.4, 1.9]), PTB (aRR 1.4, 95% CI [1.3, 1.4]), and early term birth (aRR 1.1, 95% CI [1.1, 1.2]). There was no effect modification of the overall association by race/ethnicity or insurance status. COVID-19 diagnosis was associated with elevated risk of PTB in people with hypertension, diabetes, and/or obesity., Interpretation: In a large population-based study, COVID-19 diagnosis increased the risk of VPTB, PTB, and early term birth, particularly among people with medical comorbidities. Considering increased circulation of COVID-19 variants, preventative measures, including vaccination, should be prioritized for birthing persons., Funding: UCSF-Kaiser Department of Research Building Interdisciplinary Research Careers in Women's Health Program (BIRCWH) National Institute of Child Health and Human Development (NICHD) and the Office of Research on Women's Health (ORWH) [K12 HD052163] and the California Preterm Birth Initiative, funded by Marc and Lynn Benioff., Competing Interests: The authors have no conflicts of interest to disclose., (© 2021 The Authors. Published by Elsevier Ltd.)

Background: Cannabis use and cannabis use disorders are increasing in prevalence, including among pregnant women. The objective was to evaluate the association of a cannabis-related diagnosis (CRD) in pregnancy and adverse maternal and infant outcomes., Methods: We queried an administrative birth cohort of singleton deliveries in California between 2011-2017 linked to maternal and infant hospital discharge records. We classified pregnancies with CRD from International Classification of Disease codes. We identified nicotine and other substance-related diagnoses (SRD) in the same manner. Outcomes of interest included maternal (hypertensive disorders) and infant (prematurity, small for gestational age, NICU admission, major structural malformations) adverse outcomes., Results: From 3,067,069 pregnancies resulting in live births, 29,112 (1.0 %) had a CRD. CRD was associated with an increased risk of all outcomes studied; the strongest risks observed were for very preterm birth (aRR 1.4, 95 % CI 1.3, 1.6) and small for gestational age (aRR 1.4, 95 % CI 1.3, 1.4). When analyzed with or without co-exposure diagnoses, CRD alone conferred increased risk for all outcomes compared to no use. The strongest effects were seen for CRD with other SRD (preterm birth aRR 2.3, 95 % CI 2.2, 2.5; very preterm birth aRR 2.6, 95 % CI 2.3, 3.0; gastrointestinal malformations aRR 2.0, 95 % CI 1.6, 2.6). The findings were generally robust to unmeasured confounding and misclassification analyses., Conclusions: CRD in pregnancy was associated with increased risk of adverse maternal and infant outcomes. Providing education and effective treatment for women with a CRD during prenatal care may improve maternal and infant health., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: While mental health conditions such as postpartum depression are common, little is known about how mental healthcare utilization varies after term versus preterm delivery., Objective: This study aimed to determine whether preterm birth is associated with postpartum inpatient and emergency mental healthcare utilization., Study Design: The study sample was obtained from a database of live-born neonates delivered in California between the years of 2011 and 2017. The sample included all people giving birth to singleton infants between the gestational age of 20 and 44 weeks. Preterm birth was defined as <37 weeks' gestation. Emergency department visits and hospitalizations with a mental health diagnosis within 1 year after birth were identified using International Classification of Diseases codes. Logistic regression was used to compare relative risks of healthcare utilization among people giving birth to preterm infants vs term infants, adjusting for the following covariates: age, race or ethnicity, parity, previous preterm birth, body mass index, tobacco use, alcohol or drug use, hypertension, diabetes mellitus, adequacy of prenatal care, education, insurance payer, and the presence of a mental health diagnosis before birth. Results were then stratified by mental health diagnosis before birth to determine whether associations varied based on mental health history., Results: Of our sample of 3,067,069 births, 6.7% were preterm. In fully adjusted models, compared with people giving birth to term infants, people giving birth to preterm infants had a 1.5 times (relative risk; 95% confidence interval, 1.4-1.7) and 1.3 times (relative risk; 95% confidence interval, 1.2-1.4) increased risk of being hospitalized with a mental health diagnosis within 3 months and 1 year after delivery, respectively. People giving birth to preterm infants also had 1.4 times (95% confidence interval, 1.3-1.5) and 1.3 times (95% confidence interval, 1.2-1.4) increased risk of visiting the emergency department for a mental health diagnosis within 3 months and 1 year after birth, respectively. Stratifying by preexisting mental health diagnosis, preterm birth was associated with an elevated risk of mental healthcare utilization for people with and without a previous mental health diagnosis., Conclusion: We found that preterm birth is an independent risk factor for postpartum mental healthcare utilization. Our findings suggest that screening for and providing mental health resources to birthing people after delivery are crucial, particularly among people giving birth to preterm infants, regardless of mental health history., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Identifying preterm infants at risk for mortality or major morbidity traditionally relies on gestational age, birth weight, and other clinical characteristics that offer underwhelming utility. We sought to determine whether a newborn metabolic vulnerability profile at birth can be used to evaluate risk for neonatal mortality and major morbidity in preterm infants., Methods: This was a population-based retrospective cohort study of preterm infants born between 2005 and 2011 in California. We created a newborn metabolic vulnerability profile wherein maternal/infant characteristics along with routine newborn screening metabolites were evaluated for their association with neonatal mortality or major morbidity., Results: Nine thousand six hundred and thirty-nine (9.2%) preterm infants experienced mortality or at least one complication. Six characteristics and 19 metabolites were included in the final metabolic vulnerability model. The model demonstrated exceptional performance for the composite outcome of mortality or any major morbidity (AUC 0.923 (95% CI: 0.917-0.929). Performance was maintained across mortality and morbidity subgroups (AUCs 0.893-0.979)., Conclusions: Metabolites measured as part of routine newborn screening can be used to create a metabolic vulnerability profile. These findings lay the foundation for targeted clinical monitoring and further investigation of biological pathways that may increase the risk of neonatal death or major complications in infants born preterm., Impact: We built a newborn metabolic vulnerability profile that could identify preterm infants at risk for major morbidity and mortality. Identifying high-risk infants by this method is novel to the field and outperforms models currently in use that rely primarily on infant characteristics. Utilizing the newborn metabolic vulnerability profile for precision clinical monitoring and targeted investigation of etiologic pathways could lead to reductions in the incidence and severity of major morbidities associated with preterm birth.

Competing Interests: Competing interests: All authors have completed the ICMJE Unified Competing Interest form (available upon request from the corresponding author) and declare no conflicts of interest.

Objectives: To investigate racial/ethnic differences in rehospitalization and mortality rates among premature infants over the first year of life., Study Design: A retrospective cohort study of infants born in California from 2011 to 2017 (n = 3,448,707) abstracted from a California Office of Statewide Health Planning and Development database. Unadjusted Kaplan-Meier tables and logistic regression controlling for health and sociodemographic characteristics were used to predict outcomes by race/ethnicity., Results: Compared to White infants, Hispanic and Black early preterm infants were more likely to be readmitted; Black late/moderate preterm (LMPT) infants were more likely to be readmitted and to die after discharge; Hispanic and Black early preterm infants with BPD were more likely to be readmitted; Black LMPT infants with RDS were more likely to be readmitted and die after discharge., Conclusions: Racial/ethnic disparities in readmission and mortality rates exist for premature infants across several co-morbidities. Future studies are needed to improve equitability of outcomes.

Aims: To evaluate the clinical utility of first and second trimester prenatal screening biomarkers for early pregnancy prediction of gestational diabetes mellitus (GDM) risk in nulliparous women., Methods: We conducted a population-based cohort study of nulliparous women participating in the California Prenatal Screening Program from 2009 to 2011 (n = 105,379). GDM was ascertained from hospital discharge records or birth certificates. Models including maternal characteristics and prenatal screening biomarkers were developed and validated. Risk stratification and reclassification were performed to assess clinical utility of the biomarkers., Results: Decreased levels of first trimester pregnancy-associated plasma protein A (PAPP-A) and increased levels of second trimester unconjugated estriol (uE 3 ) and dimeric inhibin A (INH) were associated with GDM. The addition of PAPP-A only and PAPP-A, uE 3 , and INH to maternal characteristics resulted in small, yet significant, increases in area under the receiver operating characteristic curve (AUC) (maternal characteristics only: AUC 0.714 (95% CI 0.703-0.724), maternal characteristics + PAPP-A: AUC 0.718 (95% CI 0.707-0.728), maternal characteristics + PAPP-A, uE 3 , and INH: AUC 0.722 (0.712-0.733)); however, no net improvement in classification was observed., Conclusions: PAPP-A, uE 3 , and INH have limited clinical utility for prediction of GDM risk in nulliparous women. Utility of other readily accessible clinical biomarkers in predicting GDM risk warrants further investigation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Preterm infants suffer from respiratory morbidity especially during the first year of life., Objective: To investigate the association of air quality and sociodemographic indicators on hospital admission rates for respiratory causes., Methods: This is a retrospective cohort study. We identified all live-born preterm infants in California from 2007 to 2012 in a population-based administrative data set and linked them to a data set measuring several air quality and sociodemographic indicators at the census tract level. All sociodemographic and air quality predictors were divided into quartiles (first quartile most favourable to the fourth quartile least favourable). Mixed effect logistic models to account for clustering at the census tract level were used to investigate associations between chronic air quality and sociodemographic indicators respiratory hospital admission during the first year of life., Results: Of 205 178 preterm infants, 5.9% (n = 12 033) were admitted to the hospital for respiratory causes during the first year. In the univariate analysis, comparing the first to the fourth quartile of chronic ozone (risk ratio [RR] 1.29, 95% confidence interval [CI] 1.21, 1.37), diesel (RR 1.10, 95% CI 1.02, 1.17) and particulate matter 2.5 (RR 1.07, 95% CI 1.01, 1.14) exposure were associated with hospital admission during the first year. Following adjustment for confounders, the risk ratios for hospital admission during the first year were 1.53 (95% CI 1.37, 1.72) in relation to educational attainment (per cent of the population over age 25 with less than a high school education) and 1.23 (95% CI 1.09, 1.38) for poverty (per cent of the population living below two times the federal poverty level)., Conclusions: Among preterm infants, respiratory hospital admissions in the first year in California are associated with socioeconomic characteristics of the neighbourhood an individual is living in., (© 2020 John Wiley & Sons Ltd.)

Background Infants with critical congenital heart disease (CCHD) are more likely to be small for gestational age (SGA) or born to mothers with maternal placental syndrome. The objective of this study was to investigate the relationship between maternal placental syndrome, SGA, and gestational age (GA) on 1-year mortality in infants with CCHD. Methods and Results In a population-based administrative database of all live-born infants in California (2007-2012) we identified all infants with CCHD without chromosomal anomalies. Our primary predictor was an impaired fetal environment (IFE), defined as presence of maternal placental syndrome or SGA. We calculated hazard ratios to quantify the association between different components of IFE and 1-year mortality and conducted a causal mediation analysis to assess GA at birth as a mediator. We identified 6863 infants with CCHD. IFE was present in 25.1%. Infants with IFE were more likely to die than infants without IFE (16.6% versus 11.1%; hazard ratios 1.55, 95% CI 1.34-1.78). Only SGA (hazard ratios 1.76, 95% CI 1.50-2.05) and placental abruption (hazard ratios 1.70, 95% CI 1.17-2.48) were significantly associated with mortality; preeclampsia and gestational hypertension had no significant association with mortality. The mediation analysis showed that 32.8% (95% CI 24.9-47.0%) of the relationship between IFE and mortality is mediated through GA. Conclusions IFE is a significant contributor to outcomes in the CCHD population. SGA and placental abruption are the main drivers of postnatal mortality while other maternal placental syndrome components had much less of an impact. Only one third of the effect between IFE and mortality is mediated through GA.

Objective: Examine factors influencing late (> sixth month of gestation) entry into prenatal care by race/ethnicity and insurance payer. Methods: The study population was drawn from singleton live births in California from 2007 to 2012 in the birth cohort file maintained by the California Office of Statewide Health Planning and Development, which includes linked birth certificate and mother and infant hospital discharge records. The sample was restricted to infants delivered between 20 and 44 weeks gestation. Logistic regression was used to calculate relative risks (RR) and 95% confidence intervals (CI) for factors influencing late entry into prenatal care. Maternal age, education, smoking, drug or alcohol abuse/dependence, mental illness, participation in the Women, Infants and Children's program and rural residence were evaluated for women entering prenatal care > sixth month of gestation compared with women entering < fourth month. Backwards stepwise logistic regression was used to create final multivariable models of risk and protective factors for late prenatal care entry for each race or ethnicity and insurance payer. Results: The sample included 2,963,888 women. The percent of women with late entry into prenatal care was consistently higher among women with public versus private insurance. Less than 1% of white non-Hispanic and Asian women with private insurance entered prenatal care late versus more than 4% of white non-Hispanic and black women with public insurance. After stratifying by race or ethnicity and insurance status, women less than 18 years of age were more likely to enter prenatal care late, with young Asian women with private insurance at the highest risk (15.6%; adjusted RR 7.4, 95%CI 5.3-10.5). Among all women with private insurance, > 12-year education or age >34 years at term reduced the likelihood of late prenatal care entry (adjusted RRs 0.5-0.7). Drugs and alcohol abuse/dependence and residing in a rural county were associated with increased risk of late prenatal care across all subgroups (adjusted RRs 1.3-3.8). Participation in the Women, Infants, and Children's program was associated with decreased risk of late prenatal care for women with public insurance (adjusted RRs 0.6-0.7), but increased risk for women with private insurance (adjusted RRs 1.4-2.1). Conclusions: The percent of women with late entry into prenatal care was consistently higher among women with public insurance. Younger women, women with <12-year education, those who used drugs or alcohol or resided in rural counties were more likely to enter prenatal care late, with Asian women <18 years at especially high risk. Participation in the Women, Infants, and Children's program and maternal age >34 years at delivery increased the likelihood of late prenatal care for some subgroups of women and decreased the likelihood for others. These findings can inform institutional factors influencing late prenatal care, especially among lower income women, and may assist efforts aimed at encouraging earlier entry into prenatal care. Rationale: Optimal prenatal care includes initiation before the 14th week of gestation. Beginning care in the first trimester provides an opportunity for sonographic pregnancy dating or confirmation with best accuracy, which can later prove critical for management of preterm labor, maternal or fetal complications, or prolonged pregnancy. In order to improve maternal and infant health by increasing the number of women seeking prenatal care in the first trimester, it is important to examine the drivers for late entry. Here, we examine factors influencing late (> sixth month of gestation) entry into prenatal care by race/ethnicity and insurance payer. We found the percent of women with late entry into prenatal care was consistently higher among women with public insurance. Younger women, women with <12-year education, those who used drugs or alcohol or resided in rural counties were more likely to enter prenatal care late, with Asian women <18 years at especially high risk. These findings can inform institutional factors influencing late prenatal care, especially among lower income women, and may assist efforts aimed at encouraging earlier entry into prenatal care.

Background: Few studies have examined the relationship between sexually transmitted infections (STIs) and preterm birth (<37 weeks gestation) by subtype (<32 weeks, 32-36 weeks, spontaneous, provider-initiated). Here, we evaluate the odds of preterm (by subtype) and early-term (37 and 38 weeks gestation) birth in women with an STI compared with a propensity score-matched reference population., Methods: The sample was selected from California births in 2007 to 2012. Sexually transmitted infection was defined as a maternal diagnosis of chlamydia, gonorrhea, or syphilis in the birth certificate or hospital discharge record. A reference sample of women without an STI was selected using exact propensity score matching on maternal factors. Odds of preterm and early-term birth were calculated., Results: Sixteen thousand three hundred twelve women were identified as having an STI during pregnancy and an exact propensity score-matched control was identified for 97.2% (n = 15,860). Women with an indication of syphilis during pregnancy were at 1.6 times higher odds of having a preterm birth and, in particular, at elevated odds of a birth less than 32 weeks due to preterm premature rupture of the membranes or provider-initiated birth (odds ratios 4.0-4.2). Women with gonorrhea were at increased odds of a preterm birth, a birth less than 32 weeks, or an early-term birth (odds ratios 1.2-1.8). Chlamydia did not raise the odds of either a preterm or early-term birth., Conclusions: Gonorrhea and syphilis increased the odds of a preterm birth. Gonorrhea also increased the odds of an early-term birth. Chlamydia did not raise the odds of an early birth.

Implementation of dietary and lifestyle interventions prior to and early in pregnancy in high risk women has been shown to reduce the risk of gestational diabetes mellitus (GDM) development later in pregnancy. Although numerous risk factors for GDM have been identified, the ability to accurately identify women before or early in pregnancy who could benefit most from these interventions remains limited. As nulliparous women are an under-screened population with risk profiles that differ from their multiparous counterparts, development of a prediction model tailored to nulliparous women may facilitate timely preventive intervention and improve maternal and infant outcomes. We aimed to develop and validate a model for preconception and early pregnancy prediction of gestational diabetes mellitus based on clinical risk factors for nulliparous women. A risk prediction model was built within a large California birth cohort including singleton live birth records from 2007-2012. Model accuracy was assessed both internally and externally, within a cohort of women who delivered at University of Iowa Hospitals and Clinics between 2009-2017, using discrimination and calibration. Differences in predictive accuracy of the model were assessed within specific racial/ethnic groups. The prediction model included five risk factors: race/ethnicity, age at delivery, pre-pregnancy body mass index, family history of diabetes, and pre-existing hypertension. The area under the curve (AUC) for the California internal validation cohort was 0.732 (95% confidence interval (CI) 0.728, 0.735), and 0.710 (95% CI 0.672, 0.749) for the Iowa external validation cohort. The model performed particularly well in Hispanic (AUC 0.739) and Black women (AUC 0.719). Our findings suggest that estimation of a woman's risk for GDM through model-based incorporation of risk factors accurately identifies those at high risk (i.e., predicted risk >6%) who could benefit from preventive intervention encouraging prompt incorporation of this tool into preconception and prenatal care., Competing Interests: The authors have declared that no competing interests exist.

Objective: Examine the risk of preterm birth (PTB, < 37 weeks) and early term birth (37-38 weeks) for women with reported drug abuse/dependence., Study Design: The population was drawn from singleton livebirths in California from 2007 to 2012. Drug abuse/dependence was determined from maternal diagnostic codes (opioid, cocaine, cannabis, amphetamine, other, or polysubstance). Relative risks, adjusted for maternal factors were calculated for PTB and early term birth., Result: Of the 2,890,555 women in the sample, 1.7% (n = 48,133) had a diagnostic code for drug abuse/dependence. The percentage of PTBs varied from 11.6% (cannabis) to 24.3% (cocaine), compared with 6.7% of women without reported drug abuse/dependence., Conclusion: Women with reported drug abuse/dependence during pregnancy were at increased risk of having a PTB and all but those using cannabis were at risk of having an early term birth. Women using cocaine and polysubstance were at the highest risk of birth < 32 weeks.

Our objective was to assess the relationship between hyperbilirubinemia with and without kernicterus and metabolic profile at newborn screening. Included were 1,693,658 infants divided into a training or testing subset in a ratio of 3:1. Forty-two metabolites were analyzed using logistic regression (odds ratios (ORs), area under the receiver operating characteristic curve (AUC), 95% confidence intervals (CIs)). Several metabolite patterns remained consistent across gestational age groups for hyperbilirubinemia without kernicterus. Thyroid stimulating hormone (TSH) and C-18:2 were decreased, whereas tyrosine and C-3 were increased in infants across groupings. Increased C-3 was also observed for kernicterus (OR: 3.17; 95% CI: 1.18-8.53). Thirty-one metabolites were associated with hyperbilirubinemia without kernicterus in the training set. Phenylalanine (OR: 1.91; 95% CI: 1.85-1.97), ornithine (OR: 0.76; 95% 0.74-0.77), and isoleucine + leucine (OR: 0.63; 95% CI: 0.61-0.65) were the most strongly associated. This study showed that newborn metabolic function is associated with hyperbilirubinemia with and without kernicterus., (© 2018 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

We examined the association between gastroschisis and preterm birth (PTB, <37 weeks) by subtype. The sample was drawn from singleton live births in California from 2007 to 2012 contained in a birth cohort file maintained by the California Office of Statewide Health Planning and Development (n = 2,891,965; 1,421 with gastroschisis). Relative risks (RRs) and 95% confidence intervals (CIs) were calculated for PTB by gestational age (<34, 34-36, and any <37 weeks) and by type (spontaneous labor with intact membranes, preterm premature rupture of the membranes [PPROM], provider initiated) and were adjusted for maternal characteristics. Over 44.5% of infants with gastroschisis were born preterm because of spontaneous etiologies; notably, 8.4% of infants with gastroschisis were born <34 weeks because of spontaneous etiologies (adjusted RRs 9.1-12.2). Overall, 53.7% of infants with gastroschisis were born preterm compared with only 6.9% of infants without gastroschisis (adjusted RR 15.2, 95% CI 13.6-19.5) and are at particularly high risk of spontaneous PTB. Nearly 9% of infants with gastroschisis delivered <34 weeks, regardless of preterm etiology, indicating that these infants are at great risk for PTB morbidities in addition to the complications from gastroschisis., (© 2018 Wiley Periodicals, Inc.)

Maternal lipid profiles during pregnancy are associated with risk for preterm birth. This study investigates the association between maternal dyslipidemia and subsequent preterm birth among pregnant women in the state of California. Births were identified from California birth certificate and hospital discharge records from 2007-2012 (N = 2,865,987). Preterm birth was defined as <37 weeks completed gestation and dyslipidemia was defined by diagnostic codes. Subtypes of preterm birth were classified as preterm premature rupture of membranes (PPROM), spontaneous labor, and medically indicated, according to birth certificate data and diagnostic codes. The association between dyslipidemia and preterm birth was tested with logistic regression. Models were adjusted for maternal age at delivery, race/ethnicity, hypertension, pre-pregnancy body mass index, insurance type, and education. Maternal dyslipidemia was significantly associated with increased odds of preterm birth (adjusted OR: 1.49, 95%CI: 1.39, 1.59). This finding was consistent across all subtypes of preterm birth, including PPROM (adjusted OR: 1.54, 95%CI: 1.34, 1.76), spontaneous (adjusted OR: 1.51, 95%CI: 1.39, 1.65), and medically indicated (adjusted OR: 1.454, 95%CI: 1.282, 1.649). This study suggests that maternal dyslipidemia is associated with increased risk for all types of preterm birth., Competing Interests: The authors have declared that no competing interests exist.

Objective To develop a pre-pregnancy or first-trimester risk score to identify women at high risk of preterm birth. Study design In this retrospective cohort analysis, the sample was drawn from California singleton livebirths from 2007 to 2012 with linked birth certificate and hospital discharge records. The dataset was divided into a training (2/3 of sample) and a testing (1/3 of sample) set for discovery and validation. Predictive models for preterm birth using pre-pregnancy or first-trimester maternal factors were developed using backward stepwise logistic regression on a training dataset. A risk score for preterm birth was created for each pregnancy using beta-coefficients for each maternal factor remaining in the final multivariable model. Risk score utility was replicated in a testing dataset and by race/ethnicity and payer for prenatal care. Results The sample included 2,339,696 pregnancies divided into training and testing datasets. Twenty-three maternal risk factors were identified including several that were associated with a two or more increased odds of preterm birth (preexisting diabetes, preexisting hypertension, sickle cell anemia, and previous preterm birth). Approximately 40% of women with a risk score ≥ 3.0 in the training and testing samples delivered preterm (40.6% and 40.8%, respectively) compared to 3.1-3.3% of women with a risk score of 0.0 [odds ratio (OR) 13.0, 95% confidence interval (CI) 10.7-15.8, training; OR 12.2, 95% CI 9.4-15.9, testing). Additionally, over 18% of women with a risk score ≥ 3.0 had an adverse outcome other than preterm birth. Conclusion Maternal factors that are identifiable prior to pregnancy or during the first-trimester can be used create a cumulative risk score to identify women at the lowest and highest risk for preterm birth regardless of race/ethnicity or socioeconomic status. Further, we found that this cumulative risk score could also identify women at risk for other adverse outcomes who did not have a preterm birth. The risk score is not an effective screening test, but does identify women at very high risk of a preterm birth., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background Racial/ethnic and socioeconomic disparities exist in outcomes for children with congenital heart disease. We sought to determine the influence of race/ethnicity and mediating socioeconomic factors on 1-year outcomes for live-born infants with hypoplastic left heart syndrome and dextro-Transposition of the great arteries. Methods and Results The authors performed a population-based cohort study using the California Office of Statewide Health Planning and Development database. Live-born infants without chromosomal anomalies were included. The outcome was a composite measure of mortality or unexpected hospital readmissions within the first year of life defined as >3 (hypoplastic left heart syndrome) or >1 readmissions (dextro-Transposition of the great arteries). Hispanic ethnicity was compared with non-Hispanic white ethnicity. Mediation analyses determined the percent contribution to outcome for each mediator on the pathway between race/ethnicity and outcome. A total of 1796 patients comprised the cohort (n=964 [hypoplastic left heart syndrome], n=832 [dextro-Transposition of the great arteries]) and 1315 were included in the analysis (n=477 non-Hispanic white, n=838 Hispanic). Hispanic ethnicity was associated with a poor outcome (crude odds ratio, 1.72; 95% confidence interval [CI], 1.37-2.17). Higher maternal education (crude odds ratio 0.5; 95% CI , 0.38-0.65) and private insurance (crude odds ratio, 0.65; 95% CI , 0.45-0.71) were protective. In the mediation analysis, maternal education and insurance status explained 33.2% (95% CI , 7-66.4) and 27.6% (95% CI , 6.5-63.1) of the relationship between race/ethnicity and poor outcome, while infant characteristics played a minimal role. Conclusions Socioeconomic factors explain a significant portion of the association between Hispanic ethnicity and poor outcome in neonates with critical congenital heart disease. These findings identify vulnerable populations that would benefit from resources to lessen health disparities.

Objective: We hypothesized second trimester serum cortisol would be higher in spontaneous preterm births compared to provider-initiated (previously termed 'medically indicated') preterm births., Study Design: We used a nested case-control design with a sample of 993 women with live births. Cortisol was measured from serum samples collected as part of routine prenatal screening. We tested whether mean-adjusted cortisol fold-change differed by gestational age at delivery or preterm birth subtype using multivariable linear regression., Result: An inverse association between cortisol and gestational age category (trend p = 0.09) was observed. Among deliveries prior to 37 weeks, the mean-adjusted cortisol fold-change values were highest for preterm premature rupture of the membranes (1.10), followed by premature labor (1.03) and provider-initiated preterm birth (1.01), although they did not differ statistically., Conclusion: Cortisol continues to be of interest as a marker of future preterm birth. Augmentation with additional biomarkers should be explored.

Objective: To evaluate if mid-pregnancy immune and growth-related molecular factors predict preterm birth (PTB) with and without (±) preeclampsia., Study Design: Included were 400 women with singleton deliveries in California in 2009-2010 (200 PTB and 200 term) divided into training and testing samples at a 2:1 ratio. Sixty-three markers were tested in 15-20 serum samples using multiplex technology. Linear discriminate analysis was used to create a discriminate function. Model performance was assessed using area under the receiver operating characteristic curve (AUC)., Results: Twenty-five serum biomarkers along with maternal age <34 years and poverty status identified >80% of women with PTB ± preeclampsia with best performance in women with preterm preeclampsia (AUC = 0.889, 95% confidence interval (0.822-0.959) training; 0.883 (0.804-0.963) testing)., Conclusion: Together with maternal age and poverty status, mid-pregnancy immune and growth factors reliably identified most women who went on to have a PTB ± preeclampsia.

We examined the risk of preterm birth (PTB, <37 weeks' gestation) in a second pregnancy and analyzed the extent to which this risk varies by maternal age and race/ethnicity. The sample included nulligravida mothers in California who delivered two singletons between 2005 and 2011. Logistic regression was used to calculate the odds of PTB in the second pregnancy. Within each race/ethnicity stratum, women delivering term infants in their first pregnancy and between 25 and 34 years old for both pregnancies served as the referent group. There were 2,90,834 women included in the study. Among women who delivered their first infant at term, the odds of delivering their second infant early differed by race and age. Hispanic, Black and Asian non-Hispanic women who were <18 years for both pregnancies were at higher odds of having a PTB in their second pregnancy (adjusted odds ratios 1.7, 3.3 and 2.9, respectively). Asian non-Hispanic women who were <18 years for their first delivery at term and between 18 and 24 years for their second delivery, or were >34 years for both, were also at higher odds of delivering their second baby prematurely (adjusted odds ratios 1.9 and 1.3, respectively). Women who deliver their first infant at <37 weeks of gestation are at 3 to 7 times higher odds of delivering their second infant preterm. Providers should consider including information about these risks in counseling their patients.

Objective: To evaluate the association between early metabolic profiles combined with infant characteristics and survival past 7 days of age in infants born at 22-25 weeks of gestation., Study Design: This nested case-control consisted of 465 singleton live births in California from 2005 to 2011 at 22-25 weeks of gestation. All infants had newborn metabolic screening data available. Data included linked birth certificate and mother and infant hospital discharge records. Mortality was derived from linked death certificates and death discharge information. Each death within 7 days was matched to 4 surviving controls by gestational age and birth weight z score category, leaving 93 cases and 372 controls. The association between explanatory variables and 7-day survival was modeled via stepwise logistic regression. Infant characteristics, 42 metabolites, and 12 metabolite ratios were considered for model inclusion. Model performance was assessed via area under the curve., Results: The final model included 1 characteristic and 11 metabolites. The model demonstrated a strong association between metabolic patterns and infant survival (area under the curve [AUC] 0.885, 95% CI 0.851-0.920). Furthermore, a model with just the selected metabolites performed better (AUC 0.879, 95% CI 0.841-0.916) than a model with multiple clinical characteristics (AUC 0.685, 95% CI 0.627-0.742)., Conclusions: Use of metabolomics significantly strengthens the association with 7-day survival in infants born extremely premature. Physicians may be able to use metabolic profiles at birth to refine mortality risks and inform postnatal counseling for infants born at <26 weeks of gestation., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

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Background: Disparities exist in the rates of preterm birth and infant mortality across different racial/ethnic groups. However, only a few studies have examined the impact of race/ethnicity on the outcomes of premature infants., Objective: To report the rates of mortality and severe neonatal morbidity among multiple gestational age (GA) groups stratified by race/ethnicity., Methods: A retrospective cohort study utilizing linked birth certificate, hospital discharge, readmission, and death records up to 1 year of life. Live-born infants ≤36 weeks born in the period 2007-2012 were included. Maternal self-identified race/ethnicity, as recorded on the birth certificate, was used. ICD-9 diagnostic and procedure codes captured neonatal morbidities (intraventricular hemorrhage, retinopathy of prematurity, periventricular leukomalacia, bronchopulmonary dysplasia, and necrotizing enterocolitis). Multiple logistic regression was performed to evaluate the impact of race/ethnicity on mortality and morbidity, adjusting for GA, birth weight, sex, and multiple gestation., Results: Our cohort totaled 245,242 preterm infants; 26% were white, 46% Hispanic, 8% black, and 12% Asian. At 22-25 weeks, black infants were less likely to die than white infants (odds ratio [OR] 0.76; 95% confidence interval [CI] 0.62-0.94). However, black infants born at 32-34 weeks (OR 1.64; 95% CI 1.15-2.32) or 35-36 weeks (OR 1.57; 95% CI 1.00-2.24) were more likely to die. Hispanic infants born at 35-36 weeks were less likely to die than white infants (OR 0.66; 95% CI 0.50-0.87). Racial disparities at different GAs were also detected for severe morbidities., Conclusions: The impact of race/ethnicity on mortality and severe morbidity varied across GA categories in preterm infants. Disparities persisted even after adjusting for important potential confounders., (© 2017 S. Karger AG, Basel.)

Objective: Examine the risk of preterm birth (PTB) among women who use drugs during pregnancy and have elevated α-fetoprotein (AFP)., Study Design: The sample included California singleton live births in 2005 to 2010 contained within a hospital discharge database linked to the Prenatal Screening Program. A selection of mothers who did not use drugs was selected at a ratio of 4:1. Risk of PTB was calculated using adjusted odds ratios and 95% confidence intervals (CIs) for women who did or did not use drugs by their AFP percentile., Results: We identified 7190 women who used drugs and selected 28 760 women who did not. Of women using cocaine with AFP ⩾95th percentile, 43.8% delivered prematurely. Women using drugs with AFP ⩾95th percentile were 11 to 35 times as likely to deliver <32 weeks., Conclusion: The combination of drug use and elevated AFP results in high rates of PTB. This combination results in an additive risk.