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Purpose To evaluate the effects of the association between first trimester vitamin D (VitD) concentrations and increased prepregnancy body mass index (BMI) on early fetal growth restriction (FGR). Methods This retrospective cohort study included 15,651 women with singleton pregnancy who delivered at the International Peace Maternity and Child Health Hospital between January 2015 and November 2016. Women were classified in two groups based on their serum 25(OH)D vitamin levels status: VitD sufficient (SUFF) group and VitD insufficient or deficient (INSUFF/DEF). The cut-off point for VitD concentration was 50.00 nmol/L. Comparisons were made between women with normal prepregnancy body weight (BMI 18.5–23.9 kg/m2) and overweight and obese (OWO) women (BMI > 24.0 kg/m2). Early FGR was defined as first-trimester gestational age-adjusted crown-rump length (CRL) in the lowest 20th centile of the population. Multivariate logistic regression was used to evaluate the association between maternal serum 25(OH)D levels and prepregnancy BMI with first trimester CRL and early FGR. Results In VitD INSUFF/DEF group, the first trimester CRL was decreased (P = 0.005), and the risk of early FGR was increased by 13% (95% CI 1.04–1.24, P = 0.004) compared to the VitD SUFF group. In OWO group, the first trimester CRL was also significantly decreased (P P P for interaction = 0.02) and the risk of early FGR (P for interaction = 0.07). Conclusion Sufficient first trimester serum 25(OH)D concentration was a protective factor for early fetal growth, especially among OWO mothers. Chinese Clinical Trial Registry (Registration number: ChiCTR1900027447 with date of registration on November 13, 2019-retrospectively registered).

Previous epidemiological evidence mainly focused on the adverse effects of prenatal exposure to pyrethroid insecticides (PYRs) on respiratory health during childhood. It remains unclear whether the PYR exposures can also impact on children's lung function.To explore the potential effects of prenatal PYR exposures on lung function in a population of Chinese children.This study included 233 mother-child dyads from the Laizhou Wan Birth Cohort (LWBC), Shandong province, northern China, between September 2010 and December 2013. Three metabolites of PYRs [3-phenoxybenzoic acid (3-PBA), and cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-DCCA and trans-DCCA)] were measured using gas chromatography-mass spectrometry (GC-MS) in maternal urine samples collected at recruitment. Lung function was assessed with spirometry in children aged 6-8 years. Multivariable linear regression and generalized linear models (GLMs) assessed the associations of prenatal PYR exposures with lung function in children.Among the PYR metabolites, 3-PBA (81.5%) were most frequently detected, followed by trans-DCCA (55.4%) and cis-DCCA (21.9%). The 3-PBA concentration was associated with a 1% decrease in FEVPrenatal 3-PBA concentrations were associated with a modest decrease in FEV

Background There is no clear consensus on the management of caesarean scar pregnancy (CSP), a complex and life-threatening condition. The objective of this study was to present a novel approach to management of CSP that combines medical therapy of multidose methotrexate and mifepristone with active surgical management by uterine curettage and consecutive local haemostasis. Case presentation We report on a prospective case series of six women with first trimester pregnancy, in whom the diagnosis of CSP was confirmed by 2D and color Doppler transvaginal ultrasound and serial hormone chorionic gonadotropin (hCG) testing. Women were between 23 and 36 years old and had at least one previous delivery by caesarean. At admission, gestational age ranged between 6 to 14 weeks, and serum hCG levels between 397 and 23,000 mUI/ml. Upon decision of pregnancy termination, medical management was undertaken in all cases and 1 mg/kg systemic Methotrexate was administered between 1 and 5 daily doses. Mifepristone was part of the treatment in cases with live pregnancy. Surgical management was employed for the cases were an embryo was seen by ultrasound, being prompted by inadequate response to Methotrexate and/or signs of miscarriage with vaginal bleeding. Curettage combined with local isthmic balloon or vaginal pack tamponade prevented further complications. High treatment rates with preservation of fertility was achieved in all patients except one who underwent hysterectomy for invasive placentation. Ultrasound and hCG levels surveillance ensured that the resolution of pregnancy was achieved. Conclusion Women with history of delivery by caesarean section should be carefully monitored in future pregnancies for prompt diagnosis of CSP. Early diagnosis of CSP allows selection of successful conservative therapy. Through this case series we contribute with our experience to the body of knowledge about the management of this serious complication of early pregnancy.

Previous studies suggested an association between female fertility and body size, but most of these studies were from Western countries and focused mainly on obesity. This study investigated the association between preconception body mass index (BMI) and time to pregnancy (TTP) in women planning to conceive from Shanghai, China. A total of 1,182 women aged 24-46 years were recruited from the Shanghai Birth Cohort between 2013 and 2015 and were followed up for 12 months. Preconception BMI was categorized as underweight, normal weight, and overweight/obesity according to the Chinese classification of BMI. Fecundability (FOR) and infertility (IOR) odds ratios were estimated using Cox (n = 1,092) and Logistic (n = 820) regression models, respectively. We found no differences in fecundability between underweight and overweight/obese women and normal-weight women. Furthermore, underweight and overweight/obese women did not have a higher risk of infertility compared with normal-weight women. Our findings suggest that non-optimal preconception BMI does not appear to influence female fecundability and infertility in Chinese women. These results should be interpreted with caution as they may be applicable only to women with demographic and anthropometric characteristics similar to our study population. Our findings need to be confirmed in other populations.

Fetal goitrous hypothyroidism is a rare condition associated with important obstetrical, neonatal complications, and neurodevelopmental impairments. Prenatal treatment remains controversial, and the risk to benefit ratio must be accurately assessed and considered for individualized management. The objective of this review was to evaluate the feasibility, safety, and effectiveness of the conservative in utero treatment of fetal goitrous hypothyroidism. In total, 25 reports that met our inclusion criteria were selected and the management of 38 cases was analyzed. Prenatal diagnosis consisted mainly of ultrasonographic findings. Fetal thyroid status was assessed by cordocentesis. Prenatal treatment varied widely in terms of levothyroxine (LT4) route of administration, dosage, number of injections, and frequency. Although different regimens and routes of administration were proposed, they seem to have similar results regarding fetal goiter reduction and thyroid status at birth. At birth, most babies had hypothyroidism, but the long-term follow-up indicated a normal psycho-neuromotor development. Our data confirm the feasibility of conservative treatment with LT4 for fetal goitrous hypothyroidism. Further studies are needed to determine the optimal management of this disorder.

Objective We compared birth injuries for spontaneous vaginal (VD) and caesarean section (CS) deliveries in preterm and term pregnancies. Methods A retrospective cohort study was conducted in a single tertiary center, between January 1st, 2007, and December 31st, 2017. The study included 62330 singleton pregnancies delivered after 24 0/7 weeks gestation. Multivariable analyses compared trauma at birth, birth hypoxia and birth asphyxia in term and preterm deliveries, stratified by mode of birth, VD versus CS. Main outcome measure was trauma at birth including intracranial laceration and haemorrhage, injuries to scalp, injuries to central and peripheral nervous system, fractures to skeleton, facial and eye injury. Results The incidence of preterm deliveries was 10.9%. Delivery of preterm babies by CS increased from 37.0% in 2007 to 60.0% in 2017. The overall incidence of all birth trauma was 16.2%. When stratified by mode of delivery, birth trauma was recorded in 23.4% of spontaneous vaginal deliveries and 7.5% of CS deliveries (aOR 3.3, 95%CI 3.1–3.5). When considered all types of birth trauma, incidence of trauma at birth was higher after 28 weeks gestation in VD compared to CS (28–31 weeks, aOR 1.7, 95% CI 1.3–2.3; 32–36 weeks, aOR 4.2, 95% CI 3.6–4.9; >37 weeks, aOR 3.3, 95% CI 3.1–3.5). There was no difference in the incidence of birth trauma before 28 weeks gestation between VD and CS (aOR 0.8, 95% CI 0.5–1.2). Regarding overall life-threatening birth trauma or injuries at birth with severe consequences such as cerebral and intraventricular haemorrhage, cranial and brachial nerve injury, fractures of long bones and clavicle, eye and facial injury, there was no difference in vaginal preterm deliveries compared to CS deliveries (p > 0.05 for all). Conclusion CS is not protective of injury at birth. When all types of birth trauma are considered, these are more common in spontaneous VD, thus favoring CS as preferred method of delivery to avoid trauma at birth. However, when stratified by severity of birth trauma, preterm babies delivered vaginally are not at higher risk of major birth trauma than those delivered by CS.

Background and Objectives: Acute urologic complications, including bladder and/or ureteric injury, are rare but known events occurring at the time of caesarean section (CS). Delayed or inadequate management is associated with increased morbidity and poor long-term outcomes. We conducted this study to identify the risk factors for urologic injuries at CS in order to inform obstetricians and patients of the risks and allow management planning to mitigate these risks. Materials and Methods: We reviewed all cases of urological injuries that occurred at CS surgeries in a tertiary university centre over a period of four years, from January 2016 to December 2019. To assess the risk factors of urologic injuries, a case-control study of women undergoing caesarean delivery was designed, matched 1:3 to randomly selected women who had an uncomplicated CS. Electronic medical records and operative reports were reviewed for socio-demographic and clinical information. Descriptive and univariate analyses were used to characterize the study population and identify the risk factors for urologic complications. Results: There were 36 patients with urologic complications out of 14,340 CS patients, with an incidence of 0.25%. The patients in the case group were older, had a lower gestational age at time of delivery and their newborns had a lower birth weight. Prior CS was more prevalent among the study group (88.2 vs. 66.7%), as was the incidence of placenta accreta and central praevia. In comparison with the control group, the intraoperative blood loss was higher in the case group, although there was no difference among the two groups regarding the type of surgery (emergency vs. elective), uterine rupture, or other obstetrical indications for CS. Prior CS and caesarean hysterectomy were risk factors for urologic injuries at CS. Conclusions: The major risk factor for urological injuries at the time of CS surgery is prior CS. Among patients with previous CS, those who undergo caesarean hysterectomy for placenta previa central and placenta accreta are at higher risk of surgical haemostasis and complex urologic injuries involving the bladder and the ureters.

Previous studies suggested that thyroid function in the first trimester of gestation played an important role in fetal growth. However, limited clinical data are available to support this relationship in the second trimester of gestation.We examined the relationship of maternal thyroid function parameters in early second trimester of gestation with birth outcomes in China.Participating 5016 mother-infant pairs were recruited from the Songjiang District Maternity and Infant Hospital, Shanghai, China, between July and December 2016. Linear regression assessed the associations of thyroid hormones with birthweight. Logistic regression tested the correlations between thyroid hormones and low birthweight, macrosomia, small for gestational age , and large for gestational age infants. Maternal serum TSH, TT3, TT4, FT3, and FT4 concentrations were measured in 16-20 weeks of gestation.TT3 and FT3 were positively associated with birthweight, while TT4 and FT4 were negatively associated with birthweight, respectively. Furthermore, higher TT3 and FT3 were associated with increased risks of LGA infants (OR = 1.48, 95% CI: 1.15-1.9; OR = 1.22, 95% CI: 1.01-1.46), respectively. Higher TT3 was associated with an increased risk of macrosomic infants (OR = 1.35, 95% CI: 1.04-1.74). In contrast, higher FT4 was associated with decreased risks of LGA (OR = 0.87, 95% CI: 0.81-0.93) and macrosomic infants (OR = 0.90, 95% CI: 0.84-0.96), respectively. No associations were found between TSH and any of the outcomes.TT3 and FT3 were positively associated with fetal growth, while TT4 and FT4 were negatively associated with fetal growth. Our findings suggested that thyroid function in early second trimester of gestation is a potential risk factor for abnormal fetal growth.

AIMS The optimal timing of delivery for twin pregnancies remains controversial. This study examined the risks of adverse neonatal outcomes and neonatal deaths according to gestational age at delivery in order to determine the optimal gestational age of delivery for twin pregnancies. METHODS This is a retrospective study of twin pregnancies delivered between 34 and 40 weeks of gestation from 1995 to 2000 in the United States. The primary outcomes evaluated were neonatal morbidity and mortality. The composite outcome of neonatal morbidity included the following variables: Apgar score lower than 7 at 5 minutes, assisted ventilation

Background: Animal studies suggest that pesticide exposure elicits endocrine changes, increases embryo implantation failure, and decreases litter size. However, only a few epidemiological studies have evaluated the effects of pesticides on the outcomes of in vitro fertilization (IVF) pregnancies. Objectives: This study examined the associations between preconception organophosphate pesticides (OP) exposure and pregnancy outcomes among women undergoing IVF in a Chinese population. Methods: This study included 522 women with infertility who underwent IVF. Women were recruited from a prospective study, the China National Birth Cohort (CNBC), from Shanghai, China, between July 2017 and December 2018. Demographic and clinical information were collected from medical records and through questionnaires. Preconception exposure to OP was assessed by measuring six nonspecific dialkylphosphate (DAP) metabolites [diethylthiophosphate (DETP), diethylphosphate (DEP), diethyldithiophosphate (DEDTP), dimethylthiophosphate (DMTP), dimethylphosphate (DMP), dimethyldithiophosphate (DMDTP)] in urine samples collected at recruitment. Generalized estimating equation (GEE) models were used to evaluate the associations between OP and pregnancy outcomes. Results: Compared with women in the lowest quartile (Q1) of individual DEP and Σ4DAP (the sum of DMP, DMTP, DEP, and DETP), women in the highest quartile (Q4) had lower odds of successful implantation, clinical pregnancy, and live birth, and most of the negative trends were significant (p-trends

Modified laparoscopic transabdominal cerclage (LTAC) was developed as a safer approach for the treatment of cervical insufficiency in pregnancy, with the cerclage tape placed lateral to the uterine vessels. We describe and review the evolution of a woman who successfully underwent an LTAC at 12 weeks of gestation, whose fetus developed growth retardation after 32 weeks. Three-dimensional power Doppler reconstruction viewed both uterine arteries (UtAs) inside of the cerclage until the second trimester. Thereafter, the visualization of UtAs showed the development of a rich array of collateral vascularization, adaptation supported by the findings of low velocity and pulsatility of blood flow in the UtAs. The appearance of the UtAs varies throughout the gestation. There is a moderate variation of the shape and curvature that could result due to their elongation. Furthermore, the cervical length increased during gestation, from 20 to 30 mm. We speculate that this is a mechanical modeling during the late gestation. More studies are needed to understand the hemodynamic and mechanical effects as well as the impact on fetal growth and development of modified LTAC in women with a short cervix or cervical incompetence.

Per- and polyfluoroalkyl substances (PFAS) are believed to impair early neurodevelopment and disrupt thyroid hormone (TH) levels. However, there are limited epidemiological data on the neurodevelopmental effects in infancy of prenatal PFAS exposure and the potential mediating effects of TH.To evaluate potential associations between prenatal PFAS exposure and early neurodevelopmental deficiencies, and assess mediator effects of TH.From 2010 to 2013, 274 mother-infant pairs were recruited to the Laizhou Wan Birth Cohort in China. Ten PFAS and five TH were measured in cord serum. Developmental quotient (DQ) from 5 domains (adaptive, social, language, gross and fine motor) was assessed using Gesell Developmental Schedules for each child at 1 year of age. The associations between PFAS and DQs were evaluated using multivariable linear regressions. TH-mediated effects of PFAS on DQs were calculated by mediation analyses.Among our study population, PFAS exposures were common and associated with DQ decrement in infants. For each 10-fold increase in PFBS concentrations, gross motor and adaptive DQ decreased by 8.56 (95%CI: -15.15, -1.97) and 5.87 (95%CI: -8.07, -3.67) points, respectively. TSH mediated 12.90% of the association of PFBS with gross motor DQ and FT4 explained 19.63% of the association of PFBS with adaptive DQ. The negative association was also found between PFHxS exposure and gross motor DQ (β = 8.14, 95%CI: -15.39, -0.98).PFBS and PFHxS were negatively associated with early neurodevelopment, especially consistent in gross motor domain. The associations were partly explained by TSH and FT4.

Background Although maternal perfluoroalkyl and polyfluroalkyl substances (PFASs) were associated with adverse birth outcomes, much less is known about their impact on infant growth during early infancy. Objectives We investigated the association between maternal PFASs exposure and infant growth during the first 12 months of life. Methods Participating 2395 pregnancies were recruited from Shanghai Birth Cohort between 2013 and 2016. Ten PFASs were quantified from maternal plasma collected during early pregnancy (median, 15 gestational weeks). We measured infant length, weight, and head circumference at birth, 42 days, 6 months, and 12 months. Linear mixed regression model was used to estimate the associations between PFAS concentrations and repeated measurements of infant growth. Effect modification by infant sex was estimated. Results Elevated perfluoroheptanoic acid (PFHpA) concentration was negatively associated with infant length-for-age Z score (LAZ) (β = −0.06, 95% confidence interval (CI): −0.11, −0.01) during the first year. Adverse associations were also observed for perfluorobutane sulfonate (PFBS) and weight-for-length Z score (WFL) (β = −0.02, 95% CI: −0.04, −0.00) and BMI-for-age Z score (BAZ) (β = −0.02, 95% CI: −0.04, −0.00). However, perfluorododecanoic acid (PFDoA) was positively associated with WFL (β = 0.03, 95% CI: 0.00, 0.06) and BAZ (β = 0.03, 95% CI: 0.00, 0.06). The adverse association of PFHpA and LAZ was more pronounced among males (β = −0.06; 95% CI: −0.11, −0.00) than females (β = 0.06; 95% CI: 0.01, 0.12). Conclusions In our study, negative associations were found for maternal PFHpA exposure and infant LAZ, PFBS and WFL and BAZ. Meanwhile, maternal PFDoA exposure was positively related with WFL and BAZ. The adverse association of maternal PFHpA exposure and infant LAZ was more pronounced among males. The results should be interpreted with caution, further prospective cohort studies with longitudinal and detailed measures are warranted to confirm these findings.

This study evaluated the feasibility of maternal C-reactive protein (CRP) in amniotic fluid (AF) as a predictor of post-partum infection in women who undergo emergency or elective caesarean section (CS). AF bacterial culture and levels of hs-CRP in maternal serum and AF were evaluated in Day 0 and three days thereafter (Day 3) in 79 women undergoing CS. Univariate analyses assessed the clinical and demographic characteristics, whereas the ROC curves assessed the feasibility of hs-CRP as marker of inflammation in women who undergo CS. There was no difference in AF, Day 0, and Day 3 serum hs-CRP levels between women with sterile compared to those with bacterial growth in AF. Among women with positive AF cultures, AF and Day 0 serum hs-CRP levels were higher in women who underwent emergency compared to those who had elective CS (p = 0.04, and p = 0.02 respectively). hs-CRP in Day 0 and Day 3 serum but not in AF has a fair predictor value of infection in emergency CS only (AUC 0.767; 95% CI 0.606–0.928, and AUC 0.791; 95% CI 0.645–0.036, respectively). We conclude that AF hs-CRP is not feasible in assessing the risk of post-cesarean inflammation or infection.

Preeclampsia is a pregnancy-related syndrome of variable severity, classically characterized by acute kidney involvement, with hypertension and/or proteinuria and reduced kidney function. Once considered a self-limited disease healed by delivery, it is now acknowledged that preeclampsia can affect cardiovascular and kidney health in the long term. The entity of risk has not been established and consequently follow-up policies have not been defined. Here we undertook a systematic review to gain better insights into the need for post–preeclampsia follow-up. Articles published between January 2000 and March 2018 were selected, dealing with at least 20 preeclampsia patients, with follow-up of 4 years or more (MEDLINE, Embase, and Cochrane Library). No quality selection or language restriction was performed. Of the 10,510 titles and abstracts originally considered, 21 papers were selected, providing information on 110,803 cases with and 2,680,929 controls without preeclampsia, with partial overlap between studies on the same databases. Heterogeneity was high, and a random meta-analytic model selected. The increase in risk of end stage renal disease after preeclampsia was significant (meta-analytic risk ratios (95% confidence interval) 6.35 (2.73-14.79)); the risk of albuminuria and chronic kidney disease increased but statistical significance was not reached (4.31 (0.95-19.58) and 2.03 (0.58-7.32), respectively). Translating meta-analytic risk into the number of patients who need follow-up to detect one adverse event, 310 patients with preeclampsia are needed to identify one woman with end stage renal disease or four to identify one woman with albuminuria. Heterogeneity in definitions, insufficient follow-up and incomplete recruitment may account for discrepancies. Thus, preeclampsia significantly increases the risk of end stage renal disease. However, there is lack of sufficient data to show a relationship between preeclampsia, albuminuria and chronic kidney disease, underlining the need for further prospective studies.

Pregnancy-related acute kidney injury (PR-AKI) is a heterogeneous disorder with multiple aetiologies that can occur at any time throughout pregnancy and the post-partum period. PR-AKI is an important obstetric complication that is associated with significant maternal and foetal morbidity and mortality. Although there has been an overall decline in the incidence of PR-AKI worldwide, a recent shift in the occurrence of this disease has been reported. Following improvements in obstetric care, PR-AKI incidence has been reduced in developing countries, whereas an increase in PR-AKI incidence has been reported in developed countries. Awareness of the physiological adaptations of the renal system is essential for the diagnosis and management of kidney impairment in pregnancy. In this review we scrutinize the factors that have contributed to the changing epidemiology of PR-AKI and discuss challenges in the diagnosis and management of acute kidney injury (AKI) in pregnancy from an obstetrics perspective. Thereafter we provide brief discussions on the diagnostic approach of certain PR-AKI aetiologies and summarize key therapeutic measures.

Few studies have examined the possible pregnancy-related risk factors for necrotizing enterocolitis (NEC)-associated deaths during infancy. Infant death due to NEC in preterm babies was identified from the US Linked Livebirth and Infant Death records between 2000 and 2004. The average number of cigarettes per day reported by the mothers who were smoking during pregnancy was classified in three categories: non-smoking, light smoking (

Recent data suggests that abnormal maternal pre-pregnancy body mass index (BMI) or gestational weight gain (GWG) is associated with unfavorable delivery outcomes. However, limited clinical evidence is available to support this correlation in China. Participating 510 mother-infant pairs were recruited from the Shanghai First Maternity and Infant Hospital, China, between January 1st and 30th 2016. Maternal pre-pregnancy BMI was categorized according to the China’s classification and GWG according to the 2009 Institute of Medicine recommendations (IOM). Linear regression tested the associations between pre-pregnancy BMI or GWG and length of gestation, birthweight, length, and head circumference. Logistic regression assessed the associations between pre-pregnancy BMI or GWG and macrosomic, small- (SGA) and large- (LGA) for-gestational-age infants. Overweight/obese women showed increased length of gestation and birthweight, but did not have a higher risk of macrosomic and LGA infants compared with normal weight women. Women with excessive GWG showed increased length of gestation, birthweight, length, and head circumference, and were more likely to deliver macrosomic and LGA infants compared with women with adequate GWG. Although a relatively low proportion of women from Shanghai area are overweight/obese or exhibit excessive GWG, both high pre-pregnancy BMI and excessive GWG influence perinatal outcomes.

The effect of prenatal mental health on the risk of obstetric interventions is unclear. The present study examined the associations between depressive and anxiety symptoms in the second and third trimesters and mode of delivery, epidural use and labor induction in a large community-based pregnancy cohort, in Alberta, Canada.Women who had singleton pregnancies, delivered in hospital, and had medical data were selected (n = 2825). Obstetric intervention data were obtained from the medical records, and depressive and anxiety symptoms were measured by the Edinburgh Postnatal Depression Scale and the Spielberger State Anxiety Inventory. Data were evaluated with multivariate multinomial and logistic regression analyses using a hierarchical modeling.After accounting for factors known to increase the risk of each intervention, including demographic variables, smoking, hospital site, gestational age, previous history of cesarean delivery, prepregnancy body mass index, assisted conception, and antepartum risk score, the only mental health variable associated with obstetric interventions was depressive symptoms in the third trimester, which increased the risk of emergency cesarean delivery (adjusted odds ratio, 2.04; 95% confidence interval, 1.26-3.29). No associations were found between antenatal depressive and anxiety symptoms and other obstetric interventions.The present findings support an association between depressive symptoms and adverse obstetric outcomes and suggest that anxiety and depression may have different effects on obstetric outcomes. Understanding the mechanism in which depression increases the risk of emergency cesarean birth needs further research.

Background Worldwide there has been a dramatic increase in the prevalence of overweight and obesity in women of childbearing age. Growing evidence suggests that maternal overweight and obesity is associated with poor maternal and perinatal outcomes. This study evaluated the impact of maternal pre-pregnancy overweight and obesity on pregnancy, labour and delivery outcomes in a cohort of women with term, singleton pregnancies cared for by family physicians in community based practices. Methods This study is a secondary analysis of the All Our Babies Cohort, a prospective, community-based pregnancy cohort in Calgary, Alberta. Maternal self-reported data on height and pre-pregnancy weight from term, singleton, cephalic pregnancies (n = 1996) were linked to clinical data on pregnancy and birth events retrieved from electronic health records. Descriptive and bivariate regression analysis were used to compare pregnancy and birth outcomes between women categorized as normal weight, overweight and obese based on the pre-pregnancy BMI. Multinomial regression analysis stratified by type of labour onset examined the association between pre-pregnancy BMI and mode of delivery controlling for maternal age, pre-existent health conditions, parity, fertility treatments, history of C-section and pregnancy complications. Results The cohort consisted of 65.8% normal weight, 23.6% overweight and 10.6% obese women. Women with increased pre-pregnancy BMI were more likely to develop pregnancy complications such as preeclampsia (OR 3.5, CI 2.0-4.6 for overweight; OR 5.3, CI 3.3-8.5 for obese) and gestational diabetes (OR 3.0, CI 1.8-5.0 for overweight; OR 6.5, CI 3.7-11.2 for obese) than normal weight women. Spontaneous onset of labour was recorded in 71.2% of women with normal pre-pregnancy BMI, whereas 39.3% of overweight and 49% of obese women had their labour induced. For women with spontaneous labour, pre-pregnancy BMI was not a significant risk factor for mode of delivery, controlling for covariates. Among women with induced labor, obesity was a significant risk factor for delivery by C-section (adjusted OR 2.2; CI 1.2-4.1). Conclusions Even among women with term, singleton pregnancies obtaining prenatal care in community-based settings, obese women who undergo labour induction are at increased risk of obstetrical interventions at delivery. These findings highlight the importance of tailored maternal care in pregnancy and at delivery of pregnant women with increased BMI in order to improve the outcomes and wellbeing of these women and their children. Electronic supplementary material The online version of this article (doi:10.1186/s12884-014-0422-y) contains supplementary material, which is available to authorized users.