Dataset Information

Prepregnancy body mass index and risk of preterm birth: association heterogeneity by preterm subgroups.

ABSTRACT:

Background

To evaluate the association between prepregnancy body mass index (BMI) is associated with early vs. late and medically-induced vs. spontaneous preterm birth (PTB) subtypes.

Methods

Using data from the Boston Birth Cohort, we examined associations of prepregnancy BMI with 189 early (<34 completed weeks) and 277 late (34-36 completed weeks) medically-induced PTBs and 320 early and 610 late spontaneous PTBs vs. 3281 term births (37-44 weeks) in multinomial regression. To assess for mediation by important pregnancy complications, we performed sequential models with and without hypertensive disorders of pregnancy, chorioamnionitis, and gestational diabetes.

Results

Prevalence of prepregnancy obesity (BMI???30.0 kg/m2) was 28% among mothers with medically-induced PTBs, 18% among mothers with spontaneous PTBs, and 18% among mothers with term births (p?=?<0.001). After adjustment for demographic and known risk factors for PTB, prepregnancy obesity was associated with higher odds of both early [OR 1.78 (1.19, 2.66)] and late [OR 1.49 (1.09, 2.04)] medically-induced PTB. These effect estimates were attenuated with inclusion of hypertensive disorders of pregnancy and gestational diabetes. For spontaneous deliveries, prepregnancy obesity was associated with decreased odds of PTB (0.76 [0.58, 0.98]) and underweight was nearly associated with increased odds of PTB (1.46 [0.99, 2.16]).

Conclusion

Prepregnancy obesity is associated with higher risk of medically-induced, but not spontaneous PTB. Hypertensive disorders of pregnancy and gestational diabetes appear to partially explain the association between prepregnancy obesity and early and late medically-induced PTB.

SUBMITTER: Parker MG

PROVIDER: S-EPMC4022544 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature

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Publications

Prepregnancy body mass index and risk of preterm birth: association heterogeneity by preterm subgroups.

Parker Margaret G MG Ouyang Fengxiu F Pearson Colleen C Gillman Matthew W MW Belfort Mandy B MB Hong Xiumei X Wang Guoying G Heffner Linda L Zuckerman Barry B Wang Xiaobin X

BMC pregnancy and childbirth 20140430

<h4>Background</h4>To evaluate the association between prepregnancy body mass index (BMI) is associated with early vs. late and medically-induced vs. spontaneous preterm birth (PTB) subtypes.<h4>Methods</h4>Using data from the Boston Birth Cohort, we examined associations of prepregnancy BMI with 189 early (<34 completed weeks) and 277 late (34-36 completed weeks) medically-induced PTBs and 320 early and 610 late spontaneous PTBs vs. 3281 term births (37-44 weeks) in multinomial regression. To a ...[more]

PMID: 24779674

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Project description:ImportanceAlthough high body mass index (BMI) is associated with adverse birth outcomes, the association with severe maternal morbidity is unclear.ObjectiveTo examine the association between prepregnancy BMI and severe maternal morbidity.Design, setting, and participantsRetrospective population-based cohort study including all singleton hospital births in Washington State, 2004-2013. Demographic data and morbidity diagnoses were obtained from linked birth certificates and hospitalization files.ExposuresPrepregnancy BMI (weight in kilograms divided by height in meters squared) categories included underweight (<18.5), normal BMI (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (≥40).Main outcomes and measuresComposite severe maternal morbidity or mortality included life-threatening conditions and conditions leading to serious sequelae (eg, amniotic fluid embolism, hysterectomy), complications requiring intensive care unit admission, and maternal death. Logistic regression was used to obtain adjusted odds ratios (ORs) and adjusted rate differences with 95% confidence intervals, adjusted for confounders (eg, maternal age and parity).ResultsOverall, 743 630 women were included in the study (mean age, 28.1 [SD, 6.0] years; 41.4% nulliparous). Prepregnancy BMI was distributed as follows: underweight, 3.2%; normal weight, 47.5%; overweight, 25.8%; obesity class 1, 13.1%; obesity class 2, 6.2%; and obesity class 3, 4.2%. Rates of severe maternal morbidity or mortality were 171.5, 143.2, 160.4, 167.9, 178.3 and 202.9 per 10 000 women, respectively. Adjusted ORs were 1.2 (95% CI, 1.0-1.3) for underweight women; 1.1 (95% CI, 1.1-1.2) for overweight women; 1.1 (95% CI, 1.1-1.2) for women with class 1 obesity; 1.2 (95% CI, 1.1-1.3) for women with class 2 obesity; and 1.4 (95% CI, 1.3-1.5) for women with class 3 obesity compared with women with normal BMI. Absolute risk increases (adjusted rate differences per 10 000 women, compared with women with normal BMI) were 28.8 (95% CI, 12.2-47.2) for underweight women, 17.6 (95% CI, 10.5-25.1) for overweight women, 24.9 (95% CI, 15.7-34.6) for women with class 1 obesity, 35.8 (95% CI, 23.1-49.5) for women with class 2 obesity, and 61.1 (95% CI, 44.8-78.9) for women with class 3 obesity.Conclusions and relevanceAmong pregnant women in Washington State, low and high prepregnancy BMI, compared with normal BMI, were associated with a statistically significant but small absolute increase in severe maternal morbidity or mortality.

Project description:BackgroundAn association between prepregnancy body mass index (BMI) and severe maternal morbidity (SMM) has been reported, but evidence has been mixed and potential explanations have not been examined.ObjectiveTo evaluate the association between prepregnancy BMI and SMM in a large, diverse birth cohort and assess potential mediation by obesity-related co-morbidities and caesarean birth.MethodsThis cohort study used linked birth certificate and hospitalisation discharge records from Californian births during 2007-2012. We assessed associations between prepregnancy BMI and SMM, and used inverse probability weighting for multiple mediators to estimate relative and absolute natural direct and indirect effects accounting for mediation by co-morbidities (hypertensive conditions, diabetes, asthma) and caesarean birth.ResultsAmong 2 650 182 births, the prevalence of SMM was 1.42%. Adjusted risk ratios for the total association between prepregnancy BMI category and SMM were 1.12 (95% confidence interval [CI] 1.07, 1.18) for underweight, 1.02 (95% CI 0.99, 1.04) for overweight, 1.04 (95% CI 1.00, 1.07) for obesity class 1, 1.14 (95% CI 1.09, 1.20) for obesity class 2, and 1.28 (95% CI 1.22, 1.36) for obesity class 3 compared to women with normal weight. After accounting for mediation by co-morbidity and caesarean birth, the risk ratios were 1.19 (95% CI 1.14, 1.26) for underweight, 0.91 (95% CI 0.89, 0.94) for overweight, 0.86 (95% CI 0.84, 0.89) for obesity class 1, 0.88 (95% CI 0.84, 0.92) for obesity class 2, and 0.89 (95% CI 0.83, 0.95) for obesity class 3.ConclusionsCo-morbidities and caesarean birth explained an association between high prepregnancy BMI and SMM. These findings suggest that promotion of healthy prepregnancy weight, along with management of co-morbidities and support of vaginal birth in pregnant women with high BMI, could reduce the risk of SMM. However, these mediators did not reduce the elevated risk of SMM observed in women with low BMI.

Project description:Previous reports have linked maternal prepregnancy obesity with low folate concentrations and child overweight or obesity (OWO) in separate studies. To our knowledge, the role of maternal folate concentrations, alone or in combination with maternal OWO, in child metabolic health has not been examined in a prospective birth cohort.To test the hypotheses that maternal folate concentrations can significantly affect child metabolic health and that sufficient maternal folate concentrations can mitigate prepregnancy obesity-induced child metabolic risk.This prospective birth cohort study was conducted at the Boston Medical Center, Boston, Massachusetts. It included 1517 mother-child dyads recruited at birth from 1998 to 2012 and followed up prospectively up to 9 years from 2003 to 2014.Child body mass index z score calculated according to US reference data, OWO defined as a body mass index in the 85th percentile or greater for age and sex, and metabolic biomarkers (leptin, insulin, and adiponectin).The mean (SD) age was 28.6 (6.5) years for mothers and 6.2 (2.4) years for the children. An L-shaped association between maternal folate concentrations and child OWO was observed: the risk for OWO was higher among those in the lowest quartile (Q1) as compared with those in Q2 through Q4, with an odds ratio of 1.45 (95% CI, 1.13-1.87). The highest risk for child OWO was found among children of obese mothers with low folate concentrations (odds ratio, 3.05; 95% CI, 1.91-4.86) compared with children of normal-weight mothers with folate concentrations in Q2 through Q4 after accounting for multiple covariables. Among children of obese mothers, their risk for OWO was associated with a 43% reduction (odds ratio, 0.57; 95% CI, 0.34-0.95) if their mothers had folate concentrations in Q2 through Q4 compared with Q1. Similar patterns were observed for child metabolic biomarkers.In this urban low-income prospective birth cohort, we demonstrated an L-shaped association between maternal plasma folate concentrations and child OWO and the benefit of sufficient folate concentrations, especially among obese mothers. The threshold concentration identified in this study exceeded the clinical definition of folate deficiency, which was primarily based on the hematological effect of folate. Our findings underscore the need to establish optimal rather than minimal folate concentrations for preventing adverse metabolic outcomes in the offspring.

Project description:ImportanceThere is a lack of evidence on the association of birth weight, childhood body mass index (BMI), change in BMI during childhood, and childhood height with subsequent risks of hidradenitis suppurativa (HS) in adulthood.ObjectiveTo investigate the association of birth weight, childhood BMI, change in BMI during childhood, and childhood height with subsequent risks of HS in adulthood in a large Danish population-based cohort.Design, setting, and participantsThis cohort study included 347 200 schoolchildren from the Copenhagen School Health Records Register born from 1930 to 1996 who were linked to the Danish National Patient Register of hospital discharge diagnoses to identify cases of HS. Birth weight was reported by parents or guardians, whereas childhood weight and height were measured by school physicians or nurses at ages 7 through 13 years. Cox proportional hazards regressions were used to estimate hazard ratios (HRs) and 95% CIs. Statistical analysis was performed from February 20, 2019, to May 15, 2019.Main outcomes and measuresA diagnosis of HS as recorded in the Danish National Patient Register.ResultsAmong the 347 200 children included in the study (175 750 boys) during the follow-up period from 1977 to 2017, 1037 individuals (677 females; median age at diagnosis, 39 years [range, 15-73 years]) received a diagnosis of HS. A nonlinear (U-shaped) association was found between birth weight and HS, such that both the lightest (2.00-2.75 kg; HR, 1.36 [95% CI, 1.10-1.68]) and the heaviest babies (4.26-5.50 kg; HR, 1.39 [95% CI, 1.01-1.93]) had increased risks of HS compared with normal-weight babies (3.26-3.75 kg; P = .04 for deviation from linearity). The risk of HS increased significantly with increasing BMI z score at each age from 7 to 13 years, from an HR of 1.32 (95% CI, 1.24-1.40) per BMI z score at 7 years of age to an HR of 1.50 (95% CI, 1.40-1.61) per BMI z score at 13 years of age. Compared with children with a normal weight at 7 and 13 years of age, those with a normal weight at 7 years of age and overweight at 13 years of age had a significantly increased risk of HS (HR, 2.11 [95% CI, 1.63-2.74]) and children with persistent overweight at both ages also had an increased risk of HS (HR, 2.61 [95% CI, 2.02-3.38]). Children with overweight at 7 years of age but with normal weight at 13 years of age did not have a significantly increased risk of HS (HR, 1.05 [95% CI, 0.67-1.67]). Childhood height at all ages was not associated with risk of HS (children at 7 years had an HR of 1.00 [95% CI, 0.94-1.07], and those 13 years had an HR of 1.06 [95% CI, 0.99-1.13], per z score).Conclusions and relevanceThis cohort study found that both the lightest and heaviest babies had increased risks of HS. Childhood BMI was positively and significantly associated with risk of HS development in adulthood. These findings suggest that returning to normal weight before puberty reduces risks of HS to levels observed in children who were never overweight. Childhood height was not associated with risk of HS.

Project description:ObjectiveTo determine recent trends in maternal prepregnancy body mass index (BMI) and to quantify its association with birth and maternal outcomes.MethodsA population-based retrospective cohort study included resident women with singleton births in the California Birth Statistical Master Files (BSMF) database from 2007 to 2016. There were 4,621,082 women included out of 5,054,968 women registered in the database. 433,886 (8.6%) women were excluded due to invalid or missing information for BMI. Exposures were underweight (BMI < 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (? 30 kg/m2) at the onset of pregnancy. Obesity was subcategorized into class I (30.0-34.9 kg/m2), class II (35.0-39.9 kg/m2), and class III (? 40 kg/m2), while adverse outcomes examined were low birth weight (LBW), very low birth weight (VLBW), macrosomic births, preterm birth (PTB), very preterm birth (VPTB), small-for-gestational-age birth (SGA), large-for-gestational-age birth (LGA), and cesarean delivery (CD). Descriptive analysis, simple linear regression, and multivariate logistic regression were performed, and adjusted odds ratios (AORs) with 95% confidence intervals (CIs) for associations were estimated.ResultsOver the ten-year study period, the prevalence of underweight and normal weight women at time of birth declined by 10.6% and 9.7%, respectively, while the prevalence of overweight and obese increased by 4.3% and 22.9%, respectively. VLBW increased significantly with increasing BMI, by 24% in overweight women and by 76% in women with class III obesity from 2007 to 2016. Women with class III obesity also had a significant increase in macrosomic birth (170%) and were more likely to deliver PTB (33%), VPTB (66%), LGA (231%), and CD (208%) than women with a normal BMI. However, obese women were less likely to have SGA infants; underweight women were 51% more likely to have SGA infants than women with a normal BMI.ConclusionsIn California from 2007 to 2016, there was a declining trend in women with prepregnancy normal weight, and a rising trend in overweight and obese women, particularly obesity class III. Both extremes of prepregnancy BMI were associated with an increased incidence of adverse neonatal outcomes; however, the worse outcomes were prominent in those women classified as obese.

Dataset Information

Prepregnancy body mass index and risk of preterm birth: association heterogeneity by preterm subgroups.

Background

Methods

Results

Conclusion

Publications

Prepregnancy body mass index and risk of preterm birth: association heterogeneity by preterm subgroups.

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