Maternal Morbidity - Obesity and Pregnancy Resources

Objective: The purpose of this study was to evaluate the relationship between prepregnancy maternal body mass index and spontaneous preterm birth and indicated preterm birth. Study design: This was a secondary analysis of the Maternal-Fetal Medicine Units Network, Preterm Prediction study. Patients were classified into categories that were based on their body mass index. Rates of indicated and spontaneous preterm birth were compared. Results: Five hundred ninety-seven (20.5%) of 2910 women were obese. Obese women had fewer spontaneous preterm births at !37 weeks of gestation (6.2% vs 11.2%; P ! .001) and at !34 weeks of gestation (1.5% vs 3.5%; P =.012). Women with a body mass index of !19 kg/m2 had 16.6% spontaneous preterm birth, with a body mass index of 19 to 24.9 kg/m2 had 11.3% spontaneous preterm birth, with a body mass index of 25 to 29.9 kg/m2 had 8.1% spontaneous preterm birth, with a body mass index of 30 to 34.9 kg/m2 had 7.1% spontaneous preterm birth, and with a body mass index of R35 kg/m2 had 5.2% spontaneous preterm birth (P ! .0001). Indicated delivery was responsible for an increasing proportion of preterm births with increasing body mass index (P= .001). Obese women had lower rates of cervical length !25 mm (5% vs 8%; P =.012). Multivariable regression analysis confirmed a lower rate of spontaneous preterm birth in obese gravid women (odds ratio, 0.57; 95% CI, 0.39-0.83; P =.003). Conclusion: Obesity before pregnancy is associated with a lower rate of spontaneous preterm birth.

Objective: To assess whether advanced maternal age modifies the relationship between maternal pregravid weight status, gestational weight gain patterns, and the occurrence of spontaneous preterm birth (SPB) and medically indicated preterm birth (MIPB). Methods: Retrospective cohort analysis of vital statistics data from the state of Florida for the period 2004 through 2007 comprising 311,422 singleton pregnancies (two age groups: 20–24 years old or younger women and ≥35 years or older women). Mothers were classified into five clusters based on their prepregnancy body mass index (BMI) values: non-obese (less than 30), class I obese (30.0≤BMI≤34.9), class II obese (35.0≤BMI≤39.9), class III obese (40≤BMI≤49.9), and super-obese (BMI≥50.0). Results: MIPB occurred more frequently among older than younger women [11.8% vs. 6.4%, respectively (p < 0.0001)) whereas SPB occurred more frequently among youngerwomen[11.3% vs. 10.5%, respectively (p < 0.0001)). Maternal obesity increased the risk forMIPBbut not for SPB. Regardless ofBMIstatus, the risk of MIPB was elevated among older mothers, particularly among those with suboptimal (<0.23 kg/week) and supraoptimal (>0.68 kg/week) gestational weight gain. A dose–response relationship with increasing gestational weight gain was evident (p < 0.01); the greatest risk for MIPB occurred among older mothers with weekly gestational weight gain in excess of 0.79 kg (OR = 7.76, 95% CI = 5.73–10.5). Conclusion: The occurrence of medically indicated preterm birth is positively associated with increased maternal pregravid body weight, older maternal age and extremes of gestational weight gain. Targeted pre- and inter-conception weight management efforts should be particularly encouraged in older mothers.

Objective: We aimed at (a) examining the rates of obesity over a 12-year period; (b) studying the effect of obesity and morbid obesity on gestational age and birth weight and (c) determining the influence of race on the association between maternal obesity and the gestational age of a newborn. Study Design: We conducted a retrospective analysis using data from the perinatal data set of mothers delivering at the George Washington University between 1992 and 2003. We stratified mother/infant pairs (n¼14 183) into three groups on the basis of maternal prepregnancy body mass index (BMI): not obese (BMI<30), obese (BMI 30 to 39) and morbidly obese (BMIX40). We identified all spontaneous and induced preterm deliveries in each group. Bivariate and multivariate analyses were conducted to control for significant differences between groups. Result: We identified obesity in 1707 (12%) and morbid obesity in 415 (3%) of the mothers. Obesity and morbid obesity increased over time during the study period. In crude analysis, mothers with obesity and morbid obesity were more likely to deliver prematurely (16.7 and 20.3%, respectively) when compared with nonobese women (14.5%), and were also more likely to have other complications including smoking, anemia, hypertension, diabetes and cesarean delivery. When controlling for these complications in a logistic regression model, obesity and morbid obesity were not associated with prematurity. Conclusion: There is no direct link between obesity and prematurity. Prematurity is more likely caused by medical complications that frequently occur in obese women. Further studies are needed on this growing population to test whether providing adequate prenatal care can control the associated medical conditions and subsequently ameliorate the rate of prematurity. Journal of Perinatology (2010) 30, 447–451; doi:10.1038/jp.2009.117; published online 20 August 2009 Keywords: body mass index; BMI; low birth weight; African-American; logistic regression analysis; preeclampsia.

OBJECTIVE: To estimate whether maternal obesity was associated with an increased risk for postpartum hemorrhage more than 1,000 mL and whether there was an association between maternal obesity and causes of postpartum hemorrhage and mode of delivery. METHODS: A population-based cohort study including 1,114,071 women with singleton pregnancies who gave birth in Sweden from January 1, 1997 through December 31, 2008, who were divided into six body mass index (BMI) classes. Obese women (class I–III) were compared with normal-weight women concerning the risk for postpartum hemorrhage after suitable adjustments. The use of heparin-like drugs over the BMI strata was analyzed in a subgroup. RESULTS: There was an increased prevalence of postpartum hemorrhage over the study period associated primarily with changes in maternal characteristics. The risk of atonic uterine hemorrhage increased rapidly with increasing BMI. There was a twofold increased risk in obesity class III (1.8%). No association was found between postpartum hemorrhage with retained placenta and maternal obesity. There was an increased risk for postpartum hemorrhage for women with a BMI of 40 or higher (5.2%) after normal delivery (odds ratio [OR] 1.23, 95% confidence interval [CI] 1.04 –1.45]) compared with normal-weight women (4.4%) and even more pronounced (13.6%) after instrumental delivery (OR 1.69, 95% CI 1.22–2.34) compared with normal-weight women (8.8%). Maternal obesity was a risk factor for the use of heparin-like drugs (OR 2.86, 95% CI 2.22–3.68). CONCLUSION: The increased risk for atonic postpartum hemorrhage in the obese group has important clinical implications, such as considering administration of prophylactic postpartum uterotonic drugs to this group.

Objective: The objective of this study was to estimate the effects of low and high gestational weight gain, in different maternal Body Mass Index (BMI) classes, on obstetric and neonatal outcomes. Method: A prospective population-based cohort study of 245,526 singleton termpregnancies.Women were grouped in five categories of BMI and in three gestational weight gain categories; b8 kg (low weight gain), 8—16 kg and N16 kg (high weight gain). Obstetric and neonatal outcomes were evaluated after adjustments for maternal age, parity, smoking, year of birth. Result: Obese women with low gestational weight gain had a decreased risk for the following outcomes (adjusted odds ratio; 95% confidence interval): preeclampsia (0.52; 0.42—0.62), cesarean section (0.81; 0.73—0.90), instrumental delivery (0.75; 0.63—0.88), and LGA births (0.66; 0.59—0.75). There was a 2-fold increased risk for preeclampsia and LGA infants among average and overweight women with excessive weight gain. High gestational weight gain increased the risk for cesarean delivery in all maternal BMI classes. Conclusion: The effects of high or low gestational weight gain differ depending on maternal BMI and the outcome variable studied. Obese women may benefit from a low weight gain during pregnancy.

OBJECTIVE: To establish optimal gestational weight gain for each maternal body mass index (BMI) category based on significant risk estimates of adverse maternal and fetal outcome. METHODS: The study population consisted of 298,648 singleton pregnancies delivered in Sweden between January 1, 1994, and December 31, 2004. The number of individuals in each weight gain class was compared with the number of individuals in all other weight gain classes in the same BMI group with regard to adverse maternal and fetal outcome. Odds ratios were calculated after suitable adjustments. RESULTS: The optimal gestational weight gain in women by prepregnancy BMI was 9–22 lb (4–10 kg) for BMI less than 20; 5–22 lb (2–10 kg) for BMI 20–24.9; less than 20 lb (less than 9 kg) for BMI 25–29.9; and less than 13 lb (less than 6 kg) for BMI of 30 or more. CONCLUSION: The gestational weight gain limits for BMI categories determined in this large populationbased cohort study from Swedish Medical Registers showed that a decreased risk of adverse obstetric and neonatal outcomes was associated with lower gestational weight gain limits than was earlier recommended, especially among obese women.

OBJECTIVE: The purpose of this study was to examine the association between gestational weight gain (GWG) in a woman’s first and second pregnancies. STUDY DESIGN: We conducted a retrospective observational cohort study of 27,771 women with their first and second births in North Carolina’s Pregnancy Nutrition Surveillance System database from 1996-2004. GWG was categorized as inadequate, appropriate, or excessive, according to 2009 Institute of Medicine guidelines. Covariate adjusted polytomous logistic regression was used to test the association between GWG category in the first and second pregnancy. RESULTS: Compared with women with appropriate GWG in their first pregnancy, women with excessive GWG in their first pregnancy had an odds ratio of 2.6 (95% confidence interval, 2.4 –2.7) for excessive GWG in their second pregnancy. Women with inadequate GWG in their first pregnancy were similarly likely to repeat this category in their subsequent pregnancy. CONCLUSION: GWG category in a woman’s first pregnancy is a significant predictor of GWG category in her subsequent pregnancy.

OBJECTIVE: Numerous studies in the U.S. and elsewhere have reported an increased risk of gestational diabetes mellitus (GDM) among women who are overweight or obese compared with lean or normal-weight women. Despite the number and overall consistency of studies reporting a higher risk of GDM with increasing weight or BMI, the magnitude of the association remains uncertain. This meta-analysis was conducted to better estimate this risk and to explore differences across studies. RESEARCH DESIGN AND METHODS: We identified studies from three sources: 1) a PubMed search of relevant articles published between January 1980 and January 2006, 2) reference lists of publications selected from the PubMed search, and 3) reference lists of review articles on obesity and maternal outcomes published between January 2000 and January 2006. We used a Bayesian model to perform the meta-analysis and meta-regression. We included cohort-designed studies that reported obesity measures reflecting pregnancy body mass, that had a normal-weight comparison group, and that presented data allowing a quantitative measurement of risk. RESULTS: Twenty studies were included in the meta-analysis. The unadjusted ORs of developing GDM were 2.14 (95% CI 1.82–2.53), 3.56 (3.05– 4.21), and 8.56 (5.07–16.04) among overweight, obese, and severely obese compared with normal-weight pregnant women, respectively. The meta-regression analysis found no evidence that these estimates were affected by selected study characteristics (publication date, study location, parity, type of data collection [retrospective vs. prospective], and prevalence of GDM among normal-weight women). CONCLUSIONS: Our findings indicate that high maternal weight is associated with a substantially higher risk of GDM.

OBJECTIVE: To estimate the effect of maternal habitus on detection of fetuses with major structural anomalies during second-trimester standard and targeted ultrasound examinations. METHODS: This was a retrospective cohort study of pregnancies 18 to 24 weeks that underwent ultrasonography over a 5-year period. An anomalous fetus was considered detected if a major abnormality of the relevant organ system was identified, regardless of the anticipated ultrasound detection. Anomalies were verified using a prospectively maintained database. Body mass index (BMI) was based on weight at first prenatal visit. RESULTS: There were 10,112 standard examinations in low-risk pregnancies and 1,098 targeted examinations in pregnancies with either high-risk indications or with an abnormality detected during standard ultrasonography. Detection of anomalous fetuses decreased with increasing BMI. For normal BMI, overweight, and class I, II, and III obesity, detection with standard ultrasonography was 66%, 49%, 48%, 42%, and 25%, respectively, and with targeted ultrasonography, 97%, 91%, 75%, 88%, and 75%, respectively, both P<.03. Residual anomaly risk after a normal ultrasound examination increased with increasing BMI, from 0.4% among women of normal BMI to 1.0% among obese women, P
.001. Anomaly detection was lower among women with pregestational diabetes than in those with other high-risk indications, 38% compared with 88% respectively, P<.001. CONCLUSION: With increasing maternal BMI, we found decreased detection of anomalous fetuses with either standard or targeted ultrasonography, a difference of at least 20% when women of normal BMI were compared with obese women. Anomaly detection was even less in pregnancies complicated by pregestational diabetes. Counseling may need to be modified to reflect the limitations of ultrasonography in obese women.

OBJECTIVE: The purpose of this study was to evaluate the effect of pregravid obesity and gestational diabetes mellitus (GDM) on the longitudinal accretion and distribution of adipose tissue in pregnancy. STUDY DESIGN: Women with normal glucose tolerance and GDM were evaluated before conception, early (12-14 weeks) and late (33-36 weeks) in gestation. Fat mass, lean body mass, and percent body fat were assessed longitudinally with hydrodensitometry. Serial biceps, triceps, subscapular, iliac, costal, mid thigh, and lower thigh skinfold measurements quantified the changes in fat mass distribution. Pregravid obesity was defined as >25% body fat. RESULTS: Subjects included 19 patients with GDM (5 lean women, 14 obese women), and 33 patients with normal glucose tolerance (controls; 12 lean women, 21 obese women). GDM and control subjects were similar in pregravid percent body fat (29.6% vs 27.9%, P = .47) and fat mass (20.8 kg vs 18.2 kg, P = .37). Values for subjects with GDM and controls were also similar in terms of percent body fat, fat mass, and weight gained (change in percent body fat,
0.7% vs 1.9% [P = .07]; change in fat mass, 3.8 kg vs 5.0 kg [P = .08]; change in weight, 12.0 kg vs 13.2 kg [P = .35]). Lean subjects gained more percent body fat compared with obese subjects (change in percent body fat, 3.3% vs 0.1% [P = .004]) but gained similar amounts of fat mass (change in fat mass, 4.7 kg vs 4.2 kg [P = .58]), lean body mass (7.6 kg vs 8.8 kg [P = .18]), and weight (change in weight, 12.3kg vs 13.0 kg [P = .61]) The distribution of adipose tissue that was accumulated as estimated with skinfold measurements was similar between patients with GDM and glucose tolerance (P > .05 for all changes in skinfolds), but significantly different between lean and obese patients (P< .05 for all changes in skinfolds). Lean women gained a predominance of adipose tissue peripherally over that in obese women. CONCLUSION: Lean women accrue significantly more fat mass than obese women, regardless of glucose tolerance. Pregestational obesity rather than GDM influences the distribution of adipose accretion.

Objective: The purpose of this retrospective cohort study was to review pregnancy outcomes in morbidly obese women who delivered a baby weighing 500 g or more in a large tertiary referral university hospital in Europe. Methods: Morbid obesity was defined as a BMI ≥ 40.0 kg/m2 (WHO). Only women whose BMI was calculated at their first antenatal visit were included. The obstetric outcomes were obtained from the hospital’s computerised database. Results: The incidence of morbid obesity was 0.6% in 5,824 women. Morbidly obese women were older and were more likely to be multigravidas than women with a normal BMI. The pregnancy was complicated by hypertension in 35.8% and diabetes mellitus in 20.0% of women. Obstetric interventions were high, with an induction rate of 42.1% and a caesarean section rate of 45.3%. Conclusions: Our findings show that maternal morbid obesity is associated with an alarmingly high incidence of medical complications and an increased level of obstetric interventions. Consideration should be given to developing specialised antenatal services for morbidly obese women. The results also highlight the need to evaluate the effectiveness of pre-pregnancy interventions in morbidly obese women.

ABSTRACT: The prevalence of obesity is currently rising in developed countries, making pregravid overweight one of the most common high-risk obstetric situations. Although the designs and populations of published studies vary widely, most authors agree that pregravid overweight increases maternal and fetal morbidity. Even moderate overweight is a risk factor for gestational diabetes and hypertensive disorders of pregnancy,and the risk is higher in subjects with overt obesity. Compared with normal weight, maternal overweight is related to a higher risk of cesarean deliveries and a higher incidence of anesthetic and postoperative complications in these deliveries. Low Apgar scores, macrosomia, and neural tube defects are more frequent in infants of obese mothers than in infants of normal-weight mothers. The regional distribution of fat modulates the effects of weight on carbohydrate tolerance, hemodynamic adaptation, and fetal size. Maternal obesity increases perinatal mortality. Longterm complications include worsening of maternal obesity and development of obesity in the infant. The average cost of hospital prenatal and postnatal care is higher for overweight mothers than for normal-weight mothers, and infants of overweight mothers require admission to neonatal intensive care units more often than do infants of normal-weight mothers. Preconception counseling, careful prenatal management, tight monitoring of weight gain, and long-term follow-up could minimize the social and economic consequences of pregnancies in overweight women.

Objective: To explore the association between striae gravidarum (SG) and the risk for perineal trauma (PT) in childbirth. Design: A cross-sectional study. Setting: Maternity ward in 5 university medical centers. Participants: Three hundred and eighty-five women (28.9  5.3 years old) who delivered vaginally. Methods: Striae gravidarum score was assessed using the Atwal numerical scoring system. The association was examined between PT as the outcome measure, defined by tears or laceration, and the total striae scores (TSS) obtained at the abdomen, hips, buttocks, and breast. Results: Significantly higher TSS scores were found in women with PT compared with women without PT (3.60  0.39 vs. 2.31  0.23, p5.003). Specifically, striae scores at the breast and hips were significantly higher among women who had PT. Logistic regression analysis revealed that TSS (OR50.079; 95% CI 1.012, 1.151; p5.021), as well as a rise in body mass index (BMI) during pregnancy (OR51.025; 95% CI 1.001, 1.049; p5.043) are significant predictors of PT. Conclusions: This study demonstrates a significant relation between SG and PT. The findings suggest that SG assessment may be used in the clinical setting by midwives and nurses as a simple and noninvasive tool to better define women at risk for PT.

The prevalence of obesity is growing among reproductive-age women. This is concerning because obesity has significant health-related consequences. Aside from the long-term risks of diabetes, heart disease, and some types of cancer, obesity poses immediate threats for young women including subfertility and adverse early and late pregnancy outcomes. Epidemiologic and experimental studies demonstrate associations between prepregnancy obesity and poor reproductive outcomes; however, the mechanisms involved are poorly understood. We discuss current knowledge of the pathophysiology of obesity in early reproductive events and how these events may affect reproductive outcomes including fertility and miscarriage risk. We also discuss avenues for future research and interventions to improve reproductive outcomes for obese women.

OBJECTIVE: To examine the effect of gestational weight change on pregnancy outcomes in obese women. METHODS: A population-based cohort study of 120,251 pregnant, obese women delivering full-term, liveborn, singleton infants was examined to assess the risk of four pregnancy outcomes (preeclampsia, cesarean delivery, small for gestational age births, and large for gestational age births) by obesity class and total gestational weight gain. RESULTS: Gestational weight gain incidence for overweight or obese pregnant women, less than the currently recommended 15 lb, was associated with a significantly lower risk of preeclampsia, cesarean delivery, and large for gestational age birth and higher risk of small for gestational age birth. These results were similar for each National Institutes of Health obesity class (30 –34.9, 35–35.9, and 40.0 kg/m2), but at different amounts of gestational weight gain. CONCLUSION: Limited or no weight gain in obese pregnant women has favorable pregnancy outcomes

OBJECTIVE: Pre-pregnancy obesity poses risks to both pregnant women and their infants. This study used a large population-based data source to examine trends, from 1993 through 2003, in the prevalence of pre-pregnancy obesity among women who delivered live infants. METHODS: Data from the Pregnancy Risk Assessment Monitoring System in nine states were analyzed for trends in pre-pregnancy obesity (BMI
29.0 kg/m2) overall and by maternal demographic and behavioral characteristics. Pre-pregnancy BMI was calculated from self-reported weight and height on questionnaires administered after delivery, and demographic characteristics were taken from linked birth certificates. The sample of 66,221 births was weighted to adjust for survey design, non-coverage, and non-response, and it is representative of all women delivering a live birth in each particular state. The sampled births represented 18.5% of all births in the United States. RESULTS: Pre-pregnancy obesity increased 69.3% during the study period, from 13.0% in 1993 to 1994 to 22.0% in 2002 to 2003. The percentage increase ranged from 45% to 105% for individual states. Subgroups of women with the highest prevalence of obesity in 2002 to 2003 were those who were 20 to 29 years of age, black, had three or more children, had a high school education, enrolled in Women, Infants, and Children, or were non-smokers. However, all subgroups of women examined experienced at least a 43% increase in pre-pregnancy obesity over this time period. DISCUSSION: The prevalence of pre-pregnancy obesity is increasing among women in these nine states, and this trend has important implications for all stages of reproductive health care.

Objective: To evaluate patient knowledge of the risks of maternal obesity and compare knowledge between non-obese and obese women. Study Design: A face-to-face survey was administered to 105 women at their first prenatal visit. The survey assessed their knowledge of obesityrelated risks during pregnancy, weight history and goals and health behaviors. Descriptive statistics described the entire sample. Student’s t-test and w2 tests compared knowledge between non-obese (body mass index (BMI) of <30 kgm–2) and obese (BMI of X30 kg m–2) gravidas. Result: There were 56 (54%) non-obese and 47 (46%) obese participants. There were no significant differences between the weight groups with respect to age, race, insurance, education, tobacco use and primigravity. Overall, 49% participants knew that obesity increases risks in pregnancy. The knowledge of specific risks was similar in the non-obese (60% correct) and obese (64% correct) groups (P¼0.76). Obese patients were more aware of the risk for diabetes (68 vs 96%, P<0.001). Obese

Background Excessive weight gain during pregnancy seems to increase birthweight and the off spring’s risk of obesity later in life. However, this association might be confounded by genetic and other shared eff ects. We aimed to examine the association between maternal weight gain and birthweight using state-based birth registry data that allowed us to compare several pregnancies in the same mother. Methods In this population-based cohort study, we used vital statistics natality records to examine all known births in Michigan and New Jersey, USA, between Jan 1, 1989, and Dec 31, 2003. From an initial sample of women with more than one singleton birth in the database, we made the following exclusions: gestation less than 37 weeks or 41 weeks or more; maternal diabetes; birthweight less than 500 g or more than 7000 g; and missing data for pregnancy weight gain. We examined how differences in weight gain that occurred during two or more pregnancies for each woman predicted the birthweight of her off spring, using a within-subject design to reduce confounding to a minimum. Findings Our analysis included 513 501 women and their 1 164 750 off spring. We noted a consistent association between pregnancy weight gain and birthweight (β 7·35, 95% CI 7·10–7·59, p<0·0001). Infants of women who gained more than 24 kg during pregnancy were 148·9 g (141·7–156·0) heavier at birth than were infants of women who gained 8–10 kg. The odds ratio of giving birth to an infant weighing more than 4000 g was 2·26 (2·09–2·44) for women who gained more than 24 kg during pregnancy compared with women who gained 8–10 kg. Interpretation Maternal weight gain during pregnancy increases birthweight independently of genetic factors. In view of the apparent association between birthweight and adult weight, obesity prevention eff orts targeted at women during pregnancy might be benefi cial for off spring.

Our objective was to study the effects of maternal body mass index (BMI) on the mode of delivery for primigravid and multigravid women. A retrospective cohort study was conducted at the University College Hospital Galway, Ireland, of 5162 women delivered from 2001 to 2003. BMI at the first antenatal appointment was calculated. Comparisons were made between each of the five BMI categories separately for primigravid and multigravid women in relation to gestation at delivery, age, mode of delivery, and birthweight. There were 5162 deliveries during the time period of the study; 2006 were primigravid and 3156 were multigravid women. Overall, 2.6% of women were underweight, 49.2% were normal weight, 22.8% were overweight, 19.8% were obese, and 5.6% were morbidly obese. In comparison with women of normal weight, for overweight and obese women, there was a progressive reduction in vaginal delivery rate with increasing BMI. For morbidly obese primigravida, this reduction was by 33.5% (from 83.1% to 55.3%, x2¼39.84, p<0.001), and for multigravida was by 23.6% (from 86% to 65.7%, x2¼53.05, p<0.001). Obesity conferred a two- to threefold increased risk of delivery by emergency caesarean section for both primigravid (obese, relative risk [RR] 2.16, 95% confidence interval [CI] 1.72 to 2.73; morbidly obese, RR 2.30, CI 1.61 to 3.37) and multigravid women (obese, RR 1.97, CI 1.45 to 2.67; morbidly obese, RR 2.44, CI 1.61 to 3.69). We concluded that increasing maternal BMI exerts a progressive adverse effect on vaginal delivery rates for both primigravid and multigravid women. Obese primigravida should be counseled antenatally about the 30% risk of emergency caesarean section.

Objective: To examine the association between obesity subtypes and risk of early and late pre-eclampsia. Design: Population-based retrospective study. Setting: State of Missouri maternally linked birth cohort files. Population: All singleton live births in the state of Missouri from 1989 to 2005. Methods: The body mass index (BMI) was used to classify women as normal weight (BMI = 18.5–24.9 kg/m2), class I obesity (BMI = 30–34.9 kg/m2), class II obesity (BMI = 35–39.9 kg/m2), class III obesity (BMI = 40–49.9 kg/m2) or super-obesity (BMI ‡ 50 kg/m2). Adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between obesity and the risk of pre-eclampsia were obtained from logistic regression models with adjustment for intracluster correlation. Results: The rate of pre-eclampsia increased with increasing BMI, with super-obese women having the highest incidence (13.4%). Compared with normal weight women, obese women (BMI ‡ 30 kg/m2) had a higher risk for pre-eclampsia (OR = 2.59, 95% CI = 2.87–3.01). This risk remained approximately the same for late-onset pre-eclampsia (preeclampsia occurring at 34 weeks or more of gestation) and was slightly reduced for early-onset pre-eclampsia (pre-eclampsia occurring at 34 weeks or less of gestation). Within each BMI category, the risk of pre-eclampsia increased with the rate of weight gain. Compared with normal weight mothers with moderate weight gain, super-obese women with a high rate of weight gain had the greatest risk for pre-eclampsia (OR = 7.52, 95% CI = 2.70–21.0). Conclusion: BMI and rate of weight gain are synergistic risk factors that amplify the burden of pre-eclampsia among super-obese women.

ABSTRACT Objective To determine the relation between overweight and obesity in mothers and preterm birth and low birth weight in singleton pregnancies in developed and developing countries. Design Systematic review and meta-analyses. Data sources Medline and Embase from their inceptions, and reference lists of identified articles. Study selection Studies including a reference group of women with normal body mass index that assessed the effect of overweight and obesity on two primary outcomes: preterm birth (before 37 weeks) and low birth weight (<2500 g). Data extraction Two assessors independently reviewed titles, abstracts, and full articles, extracted data using a piloted data collection form, and assessed quality. Data synthesis 84 studies (64 cohort and 20 casecontrol) were included, totalling 1 095 834 women. Although the overall risk of preterm birth was similar in overweight and obese women and women of normal weight, the risk of induced preterm birth was increased in overweight and obese women (relative risk 1.30, 95% confidence interval 1.23 to 1.37). Although overall the risk of having an infant of low birth weight was decreased in overweight and obese women (0.84, 0.75 to 0.95), the decrease was greater in developing countries than in developed countries (0.58, 0.47 to 0.71 v 0.90, 0.79 to 1.01). After accounting for publication bias, the apparent protective effect of overweight and obesity on low birth weight disappeared with the addition of imputed “missing” studies (0.95, 0.85 to 1.07), whereas the risk of preterm birth appeared significantly higher in overweight and obese women (1.24, 1.13 to 1.37). Conclusions Overweight and obese women have increased risks of preterm birth and induced preterm birth and, after accounting for publication bias, appeared to have increased risks of preterm birth overall. The beneficial effects of maternal overweight and obesity on low birth weight were greater in developing countries and disappeared after accounting for publication bias. INTRODUCTION The continuum of overweight and obesity is now the most common complication of pregnancy in many developed and some developing countries. In the United Kingdom, 33% of pregnant women are overweight or obese.1 In the United States, 12%2 to 38%3 of pregnant women are overweight and 11%4 to 40%3 are obese. In India, 8% of pregnant women are obese and 26% are overweight5 and in China, 16% are overweight or obese.6 Pretermbirth is the leading cause of neonatal mortality and morbidity and childhood morbidity7 followed by low birth weight.8 Whether maternal overweight and obesity is associated with increased,9 decreased,10 or neutral risks11 of preterm birth has been debated in the literature, with the uncertainty reflected in the American College of Obstetrics andGynecologyCommittee opinion on obesity in pregnancy.12 Even low birth weight, which is typically thought to be reduced in infants of overweight and obese women,3 is sometimes associated with neutral risks.5 To accurately risk stratify a pregnancy at the first antenatal visit, as is standard, it is important to know the effect of overweight and obesity in mothers on preterm birth and low birth weight.We therefore undertook a systematic, comprehensive, and unbiased accumulation and summary of the available evidence from all study designs with a reference group of normal weightwomen to determine the direction andmagnitude of the association of maternal overweight and obesity with preterm birth and low birth weight in singleton pregnancies in developed and developing countries. METHODS We carried out a systematic review and meta-analyses in accordance with the Meta-analysis Of Observational Studies in Epidemiology consensus statement.13 With the help of a librarian we searched Medline (1950 to 2 January 2009) and Embase (1980 to 2 January 2009), using individual comprehensive search strategies. This study was part of a constellation of systematic reviews examining maternal anthropometry and preterm birth and low birth weight (see search strategy in web extra appendix 1). Additional eligible studies were sought by reviewing the reference lists of identified articles.

Abstract We investigated the association between 2009 IOM recommendations and adverse infant outcomes by maternal prepregnancy body mass index (BMI). Birth outcomes for 570,672 women aged 18–40 years with a singleton full-term live-birth were assessed using 2004–2007 Florida live-birth certificates. Outcomes included large-for-gestational-age (LGA) and small-for-gestationalage (SGA). Associations between gestational weight change and outcomes were assessed for 10 BMI groups by calculating proportions, and logistic regression modeling was used to produce adjusted odds ratios (aORs) to account for the effect of confounders. We created comparison categories below and above recommendations using 2009 IOM recommendations as a reference. Of importance, 41.6% of women began pregnancy as overweight and obese and 51.2% gained weight excessively during pregnancy on the basis of 2009 IOM recommendations. Proportions of LGA were higher among obese women and increased with higher weight gain. Compared with recommended weight gain, aORs for LGA were lower with less than recommended gain (aOR range: 0.27–0.77) and higher with more than recommended gain (aOR range: 1.27–5.99). However, SGA was less prevalent among obese women, and the proportion of SGA by BMI was similar with higher weight gain. Gain less than recommended was associated with increased odds of SGA (aOR range: 1.11–2.97), and gain greater than recommended was associated with decreased odds of SGA (aOR range: 0.38–0.83). Gestational weight gain influenced the risk for LGA and SGA in opposite directions. Minimal weight gain or weight loss lowered risk for LGA among obese women. Compared with 1990 IOM recommendations, 2009 recommendations include weight gain ranges that are associated with lower risk of LGA and higher risk of SGA. Awareness of these tradeoffs may assist with clinical implementation of the 2009 IOM gestational weight gain recommendations. However, our results did not consider other maternal and infant outcomes related to gestational weight gain; therefore, the findings should be interpreted with caution.

We compared obstetric outcomes based on gestational weight gain in normalweight and obese women using traditional Institute of Medicine (IOM) guidelines and newly recommended Cedergren criteria. Using the New Jersey Pregnancy Risk Assessment Monitoring System (PRAMS) database and electronic birth records, perinatal outcomes were analyzed to estimate the independent effects of prepregnancy body mass index (BMI) and gestational weight gain by IOM versus Cedergren criteria. Of 9125 subjects in PRAMS database from 2002 to 2006, 53.7% had normal BMI, 12.3% were overweight, 18.2% were obese, and the rest were underweight. Among normal-weight mothers, when compared with the IOM guidelines, macrosomia (6.45% versus 4.27%) and cesarean delivery rates (30.42% versus 29.83%) were lower using Cedergren criteria but the rates of preterm delivery (5.06% versus 9.44%), low birth weight (0.38% versus 2.42%), and neonatal intensive care unit (NICU) admissions (7.02% versus 10.86%) were higher with the Cedergren criteria. Similarly, among obese patients, when compared with IOM guidelines, macrosomia (10.79% versus 5.47%) and cesarean delivery rates (43.95% versus 40.71%) were lower using Cedergren criteria but the rates of preterm delivery (6.83% versus 8.32%), low birth weight (0.87% versus 1.88%), and NICU admissions (8.92% versus 13.78%) were higher with the Cedergren criteria. Based on our results, ideal gestational weight gain is presumably somewhere between the IOM and Cedergren’s guidelines.

We assessed the impact of a lifestyle modification program (LMP) on weight gain in pregnancy and evaluated its effect on adverse pregnancy outcomes. A prospective matched controlled study design was employed. Inclusion criteria consisted of pregnant women with singleton gestations and body mass index (BMI) >30 without underlying medical conditions. In the study group, patients were prospectively enrolled in the first trimester. Through the LMP, women participated in a comprehensive program on nutrition, exercise, and weight control in pregnancy. The control group consisted of matched patients by starting BMI, parity, and socioeconomic status during the same study period cared for at the same institution. The primary outcome evaluated was weight gain in pregnancy. Adverse pregnancy outcomes including preeclampsia, gestational diabetes, gestational hypertension, and various postpartum complications were evaluated between the two groups. Statistical analysis was performed using nonparametric methods, with p<0.5 considered significant. Twenty-eight patients were recruited for this study and underwent the intervention. Patient compliance with the LMP was 75%, two patients were lost to follow-up, one had a preterm delivery, and four had incomplete data due to various reasons. Twenty-one patients completed their pregnancy and were available for analysis. Twenty matched control patients were identified for analysis. Study participants gained significantly less weight in their pregnancies when compared with controls (mean weight gain 17 versus 34 pounds, respectively; p¼0.008). Secondary outcomes of preeclampsia, gestational diabetes, cesarean section, as well as infant birth weight did not significantly differ between the groups. This study suggests an effective method of reducing prenatal weight gain in the obese population. This type of comprehensive intervention could be an important, cost-effective risk-reduction strategy.

OBJECTIVE: We sought to determine whether genetic variants associated with diabetes and obesity predict gestational weight gain. STUDY DESIGN: A total of 960 participants in the Pregnancy, Infection, and Nutrition cohorts were genotyped for 27 single-nucleotide polymorphisms (SNPs) associated with diabetes and obesity. RESULTS: Among Caucasian and African American women (n = 960), KCNQ1 risk allele carriage was directly associated with weight gain (P < .01). In Bayesian hierarchical models among Caucasian women (n = 628), we found posterior odds ratios >3 for inclusion of TCF2 and THADA SNPs in our models. Among African American women (n = 332), we found associations between risk allele carriage and weight gain for the THADA and INSIG2 SNPs. In Bayesian variable selection models, we found an interaction between the TSPAN8 risk allele and pregravid obesity, with lower weight gain among obese risk allele carriers. CONCLUSION: We found evidence that diabetes and obesity risk alleles interact with maternal pregravid body mass index to predict gestational weight gain.

Objective. Several studies have shown an increased risk for neural tube defects associated with prepregnancy maternal obesity. Because few recent studies have examined the relation between maternal prepregnancy obesity and overweight and other birth defects, we explored the relation for several birth defects and compared our findings with those of previous studies. Methods. We conducted a population-based case-control study of several selected major birth defects using data from the Atlanta Birth Defects Risk Factor Surveillance Study. Mothers who delivered an infant with and without selected birth defects in a 5-county metropolitan Atlanta area between January 1993 and August 1997 were interviewed. Maternal body mass index (BMI) was calculated from self-reported maternal prepregnancy weight and height. Women with known preexisting diabetes were excluded. The risks for obese women (BMI >30) and overweight women (BMI 25.0 –29.9) were compared with those for average-weight women (BMI 18.5– 24.9). Results. Obese women were more likely than average-weight women to have an infant with spina bifida (unadjusted odds ratio [OR]: 3.5; 95% confidence interval [CI]: 1.2–10.3), omphalocele (
OR: 3.3; 95%
CI: 1.0 –10.3), heart defects (
OR: 2.0; 95%
CI: 1.2–3.4), and multiple anomalies (
OR: 2.0; 95%
CI: 1.0 –3.8). Overweight women were more likely than average-weight women to have infants with heart defects (
OR: 2.0; 95%
CI: 1.2–3.1) and multiple anomalies (
OR: 1.9; 95%
CI: 1.1–3.4). Conclusions. Our study confirmed the previously established association between spina bifida and prepregnancy maternal obesity and found an association for omphalocele, heart defects, and multiple anomalies among infants of obese women. We also found an association between heart defects and multiple anomalies and being overweight before pregnancy. A higher risk for some birth defects is yet another adverse pregnancy outcome associated with maternal obesity. Obesity prevention efforts are needed to increase the number of women who are of healthy weight before pregnancy. Pediatrics 2003;111:1152–1158; obesity, body mass index, pregnancy, neural tube defect, congenital anomaly, birth defect.