Search

Background: Preterm delivery (PTD) includes three main presenting subtypes: spontaneous preterm labour (sPTL), preterm premature rupture of membranes (pPROM) and clinician-initiated preterm delivery (ciPTD). PTD subtype data are rarely available from birth registries and are onerous to derive from medical records. Objectives: To develop and test the validity of a questionnaire to classify PTD subtype based on birthing parent recall of labour and delivery events. Methods: The questionnaire was sent in 2022 to 581 patients with PTD history documented in the LIFECODES study, a hospital-based birth cohort in Boston, Massachusetts. Eighty-two respondents reported 94 PTDs that could be linked to medical records. Data on PTD subtype were extracted from medical records as the reference standard. Results: Medical records indicated 47 spontaneous (24 sPTL, 23 pPROM) and 47 ciPTD deliveries occurring a median eight years earlier. The sensitivity and specificity of the recall questionnaire were 88% (95% confidence interval: 68, 97%) and 89% (79, 95%) for sPTL; 96% (78, 100%) and 94% (86, 98%) for pPROM; and 83% (69, 92%) and 100% (92, 100%) for ciPTD, respectively. Greater time since pregnancy did not degrade the sensitivity or specificity of the parental recall questionnaire. Conclusions: Although derived from a modest sample, the moderate-to-high sensitivity and specificity of the parental recall questionnaire to classify sPTL, pPROM and ciPTD demonstrates its potential for large studies of PTD and for correction of misclassification bias. Future studies are required to test the questionnaire in a variety of populations. [ABSTRACT FROM AUTHOR]

Studies on the health effects of environmental mixtures face the challenge of limit of detection (LOD) in multiple correlated exposure measurements. Conventional approaches to deal with covariates subject to LOD, including complete-case analysis, substitution methods, and parametric modeling of covariate distribution, are feasible but may result in efficiency loss or bias. With a single covariate subject to LOD, a flexible semiparametric accelerated failure time (AFT) model to accommodate censored measurements has been proposed. We generalize this approach by considering a multivariate AFT model for the multiple correlated covariates subject to LOD and a generalized linear model for the outcome. A two-stage procedure based on semiparametric pseudo-likelihood is proposed for estimating the effects of these covariates on health outcome. Consistency and asymptotic normality of the estimators are derived for an arbitrary fixed dimension of covariates. Simulations studies demonstrate good large sample performance of the proposed methods vs conventional methods in realistic scenarios. We illustrate the practical utility of the proposed method with the LIFECODES birth cohort data, where we compare our approach to existing approaches in an analysis of multiple urinary trace metals in association with oxidative stress in pregnant women. [ABSTRACT FROM AUTHOR]

Objectives: The influence of placental morphologic characteristics on pregnancy outcomes is poorly understood. Our objective was to evaluate the relationship of the distance of the placental cord insertion from the placental edge (PCI‐D) with associated placental characteristics as well as birth outcomes. Methods: We performed a retrospective cohort study of nulliparous women with singleton gestations undergoing obstetric ultrasound examinations between 14 and 23 weeks' gestation with a cervical length of greater than 3.0 cm who delivered between 24 and 42 weeks. A 3‐dimensional volume of the placenta was evaluated. The PCI‐D was obtained with Virtual Organ computer‐aided analysis software (GE Healthcare, Milwaukee, WI). Generalized linear regression and generalized additive models were fitted to explore the associations between the PCI‐D in relation to demographic and clinical characteristics. Results: A total of 216 pregnancies were included in the analysis. The PCI‐D did not correlate with maternal age, gestational age at delivery, mode of delivery, or 5‐minute Apgar score. Although not statistically significant, the birth weight z score (P = .09) was associated with a longer PCI‐D, and gravidity was associated with a shorter PCI‐D (P = .10). A low‐lying placenta or placenta previa was associated with a longer PCI‐D (P = .03). Conclusions: The PCI‐D is associated with a low placental position in the second trimester. These data are helpful for understanding placental development. The PCI‐D may be associated with pregnancy‐related factors such as birth weight and multigravidity. More research is required to evaluate the effects of pregnancy‐related factors on the PCI‐D and the effect of the PCI‐D on pregnancy outcomes. [ABSTRACT FROM AUTHOR]

Background: Ultrasound measures are valuable for epidemiologic studies of risk factors for growth restriction. Longitudinal measurements enable investigation of rates of change and identification of windows where growth is impacted more acutely. However, missing data can be problematic in these studies, limiting sample size, ability to characterise windows of vulnerability, and in some instances creating bias. We sought to compare a parametric linear mixed model (LMM) approach to multiple imputation in this setting with multiple imputation by chained equation (MICE) methodology.Methods: Ultrasound scans performed for clinical purposes were abstracted from women in the LIFECODES birth cohort (n = 1003) if they were close in time to three study visits (median 18, 26, and 35 weeks' gestation). We created imputed datasets using LMM and MICE and calculated associations between demographic factors and ultrasound parameters cross-sectionally and longitudinally. Results were compared with a complete-case analysis.Results: Most participants had ultrasounds at 18 weeks' gestation, and ~50% had measurements at 26 and 35 weeks; 100% had birthweight. Associations between demographic factors and ultrasound measures were similar in magnitude, but more precise, when either imputed datasets were used, compared with a complete-case analysis, in both the cross-sectional or longitudinal analyses.Conclusions: MICE, though ignoring the non-linear features of the trajectory and within subject correlation, is able to provide reasonable imputation of foetal growth data when compared to LMM. Because it simultaneously imputes missing covariate data and does not require specification of variance structure as in LMM, MICE may be preferable for imputation in this setting. [ABSTRACT FROM AUTHOR]

Introduction: We identified patients with previa and suspected accreta who are at lowest risk of unscheduled delivery or major morbidity with planned delivery beyond 34 weeks' gestation.Material and Methods: This was a retrospective cohort study of patients who had reached 34.0 weeks' gestational age with a suspected previa-accreta. We evaluated rates of unscheduled and emergent delivery based on known risk factors for premature birth. In a second analysis, we stratified patients based on level of preoperative morbidity concern and evaluated rates of major transfusion and Intensive Care Unit admission by delivery week (34 weeks, 35 weeks or 36 weeks and beyond).Results: Of 84 available patients, we classified 31 patients as low risk for unscheduled delivery and 52 as high risk. The low risk group was scheduled later (36.6 vs. 36.0 weeks; p < 0.01), but demonstrated lower rates of unscheduled delivery prior to 36 weeks (3% vs. 19%, p = 0.05). Of the patients with no prior cesarean section, only one (7%) experienced massive blood loss even though 36% had unscheduled deliveries. We observed no significant increase in major transfusion or massive blood loss with advancing gestational age, likely due to selection of the most concerning patients for early, scheduled delivery.Conclusion: Patients with suspected previa-accreta and no risk factors for preterm birth are at low risk for an unscheduled delivery prior to 36 weeks. Those with no concern for percreta or increta or no prior cesarean section may also be candidates for later delivery. [ABSTRACT FROM AUTHOR]

Problem We assess whether inflammatory and oxidative stress markers early in pregnancy are associated with decreasing cervical length in the second trimester. Method of study This is a secondary analysis of a nested case-control study of preterm birth conducted at a tertiary care center from 2006 to 2008. Plasma inflammatory markers included the following: interleukin-6 ( IL-6), interleukin-10 ( IL-10), interleukin-1 beta ( IL-1β), tumor necrosis factor alpha ( TNF-α), and C-reactive protein ( CRP); and urine oxidative stress markers included the following: 8-hydroxydeoxyguanosine (8- OHdG) and 8-isoprostane, measured at two study visits (median 10 and 18 weeks of gestation). The primary outcome was cervical length<10th percentile measured between 16 and 24 weeks of gestation. Logistic regression models were used, adjusting for body mass index, age, race, parity, tobacco use, education, and gestational age at cervical length measurement. Results Among 384 observed women, the 10th percentile cervical length was 3.0 cm. IL-10 levels were significantly higher among women with a cervical length<10th percentile compared to women with a longer cervix (mean IL-10: 95.5 vs 25.8 pg/mL, P<.01). Similarly, IL-6 levels were significantly higher among women with a cervical length<10th percentile (mean IL-6: 25.2 vs 4.3 pg/mL, P<.01). After controlling for potential confounders, an increase in IL-10 was significantly associated with a cervical length<10th percentile at both 10 and 18 weeks (adjusted odd ratio [ AOR]: 1.74; 95% CI: 1.18-2.58; P=.005). At 18 weeks, only IL-6 was also significantly associated with a cervical length<10th percentile ( AOR: 1.54; 95% CI: 1.11-2.13; P=.009). Other inflammatory biomarkers, including CRP, IL-1β, TNF-α, and oxidative stress biomarkers, 8- OHdG and 8-isoprostane, were not associated with cervical length. Conclusion There was a significant association between the cytokines IL-6 and IL-10 early in pregnancy and decreased cervical length, suggesting an imbalance of immune regulation could impact cervical length. [ABSTRACT FROM AUTHOR]

Problem: Perturbations in normal fetal growth during pregnancy are associated with poor child and adult health outcomes. Inflammation and oxidative stress are recognized as important mechanisms in preeclampsia and preterm birth but have been examined less in relation to fetal growth. We hypothesized that maternal inflammation and oxidative stress in pregnancy would be associated with reduced fetal growth and sought to identify windows of vulnerability. Method of study: In a secondary analysis of 482 women from the LIFECODES birth cohort study, we measured inflammation (C‐reactive protein [CRP] and the cytokines IL‐1β, IL‐6, IL‐10, and TNF‐α) and oxidative stress (8‐isoprostane and 8‐hydroxydeoxyguanosine [8‐OHdG]) biomarkers in plasma and urine, respectively, at four time points during pregnancy. We examined associations between repeated measures of each marker and ultrasound (head and abdominal circumference, femur length, and a summary measure of estimated fetal weight) as well as delivery (birthweight) metrics of growth. Results: In adjusted repeated‐measures models, an interquartile range (IQR) increase in CRP was associated with a 0.12 standard deviation decrease in fetal weight z‐score (95% confidence interval, CI, −0.21, −0.02), which corresponds to approximately 50 g at 40‐week gestation. The association was greatest in magnitude (ie, most negative) with CRP measured later in pregnancy. Oxidative stress markers were not associated with fetal weight, although both were inversely associated with head circumference and femur length. Conclusion: Inflammation and oxidative stress markers measured later in pregnancy were associated with reduced fetal growth as measured by repeated ultrasound scans. [ABSTRACT FROM AUTHOR]

We thank Dr. Matsubara and colleagues(1) for commenting on our study, "Patient selection for later delivery timing with suspected previa-accreta."(2) We particularly appreciate the emphasis on individualized patient care, and that access (or lack thereof) to a tertiary center with experience in managing abnormally invasive placenta (AIP) is of paramount importance when considering delivery timing. This article is protected by copyright. All rights reserved. [ABSTRACT FROM AUTHOR]