Nulliparity and preterm birth in the era of obesity epidemic.
ABSTRACT To assess the impact of obesity on preterm birth among nulliparous women.
Retrospective cohort study of nulliparous mothers delivering infants in Florida between 2004 and 2007. Women were classified as non-obese (pre-pregnancy body mass index (BMI) <30) or obese (BMI ≥ 30). The main outcomes assessed were preterm birth, very preterm birth and extremely preterm birth. Risk estimates were obtained using logistic regression. Multiparous non-obese mothers were the referent group for all analyses.
As compared to multiparous women, nulliparous mothers had an increased risk of very preterm and extremely preterm birth with the highest risk observed for extremely preterm birth (odds ratios (OR) = 1.37, 95% CI = 1.28, 1.47) (p for trend <0.01). Obese nulliparous mothers had an elevated risk of preterm, very preterm and extremely preterm birth, with the risk of extremely preterm birth being the most pronounced (OR=1.97, 95% CI=1.75-2.22) [p for trend <0.05]. The heightened risk associated with obesity among nulliparous women was observed across all racial/ethnic sub-populations, with black nulliparous obese mothers being at greatest risk of all preterm birth-subtypes.
Obesity is a risk marker for preterm, very preterm and extremely preterm birth among first-time mothers and particularly among blacks and Hispanics.
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ABSTRACT: Preterm birth is a leading cause of infant mortality, morbidity, and long-term disability, and these risks increase with decreasing gestational age. Obesity increases the risk of preterm delivery, but the associations between overweight and obesity and subtypes of preterm delivery are not clear. To study the associations between early pregnancy body mass index (BMI) and risk of preterm delivery by gestational age and by precursors of preterm delivery. Population-based cohort study of women with live singleton births in Sweden from 1992 through 2010. Maternal and pregnancy characteristics were obtained from the nationwide Swedish Medical Birth Register. MAIN OUTCOMES AND MEASURES: Risks of preterm deliveries (extremely, 22-27 weeks; very, 28-31 weeks; and moderately, 32-36 weeks). These outcomes were further characterized as spontaneous (related to preterm contractions or preterm premature rupture of membranes) and medically indicated preterm delivery (cesarean delivery before onset of labor or induced onset of labor). Risk estimates were adjusted for maternal age, parity, smoking, education, height, mother's country of birth, and year of delivery. Among 1,599,551 deliveries with information on early pregnancy BMI, 3082 were extremely preterm, 6893 were very preterm, and 67,059 were moderately preterm. Risks of extremely, very, and moderately preterm deliveries increased with BMI and the overweight and obesity-related risks were highest for extremely preterm delivery. Among normal-weight women (BMI 18.5-<25), the rate of extremely preterm delivery was 0.17%. As compared with normal-weight women, rates (%) and adjusted odds ratios (ORs [95% CIs]) of extremely preterm delivery were as follows: BMI 25 to less than 30 (0.21%; OR, 1.26; 95% CI, 1.15-1.37), BMI 30 to less than 35 (0.27%; OR, 1.58; 95% CI, 1.39-1.79), BMI 35 to less than 40 (0.35%; OR, 2.01; 95% CI, 1.66-2.45), and BMI of 40 or greater (0.52%; OR, 2.99; 95% CI, 2.28-3.92). Risk of spontaneous extremely preterm delivery increased with BMI among obese women (BMI≥30). Risks of medically indicated preterm deliveries increased with BMI among overweight and obese women. In Sweden, maternal overweight and obesity during pregnancy were associated with increased risks of preterm delivery, especially extremely preterm delivery. These associations should be assessed in other populations.JAMA The Journal of the American Medical Association 06/2013; 309(22):2362-70. DOI:10.1001/jama.2013.6295 · 29.98 Impact Factor
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ABSTRACT: AIM: The aim of this study was to assess maternal characteristics as predictors of inadequate or excessive gestational weight gain (GWG) and to characterize maternal and neonatal outcomes associated with inadequate or excessive GWG in Asian women. MATERIAL AND METHODS: A study was conducted among 1166 Chinese, Malay, and Indian women who delivered a live singleton infant at KK Women's and Children's Hospital, Singapore. Logistic regression analysis was used to determine predictors and maternal and neonatal outcomes of inadequate or excessive GWG, relative to adequate (recommended) GWG. RESULTS: While maternal age less than 20 years, Malay ethnicity and underweight pre-pregnancy body mass index increased the risk of inadequate GWG, overweight pre-pregnancy body mass index decreased this risk. Tall stature and Malay ethnicity were associated with an increased risk of excessive GWG, while maternal age greater than 30 years was associated with a decreased risk. Inadequate GWG increased the risk of preterm birth and decreased the risk of delivery by cesarean section and postpartum weight retention at 6 months. Excessive GWG increased the risk of delivery by cesarean section, postpartum weight retention at 6, 12 and 24 months and having a high-birthweight baby. CONCLUSION: Maternal predictors and perinatal outcomes of GWG among Asian women are similar to those identified previously among Caucasian, African-American and Hispanic women.Journal of Obstetrics and Gynaecology Research 02/2013; 39(5). DOI:10.1111/j.1447-0756.2012.02067.x · 0.84 Impact Factor
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ABSTRACT: Maternal obesity is a major source of preventable perinatal morbidity, but studies of the relationship between obesity and preterm birth have been inconsistent. This review looks at two major studies covering just under 3.5 million births, from California, USA, and Sweden. Conclusion Inconsistent findings in previous studies appear to stem from the complex relationship between obesity and preterm birth. Initiatives to decrease maternal obesity represent an important strategy in reducing preterm birth.Acta Paediatrica 02/2014; 103(6). DOI:10.1111/apa.12616 · 1.97 Impact Factor