SMFM meeting paperPrepregnancy body mass index and the length of gestation at term
Section snippets
Materials and Methods
This retrospective cohort was selected from women who delivered singleton infants at the UCSF Medical Center between 1990-2001. The UCSF perinatal division maintains the research database that was used for this study. Demographic, antenatal, intrapartum, and delivery data are entered into a preprinted datasheet by the delivering physician or midwife immediately after every birth, and additional neonatal and discharge data are entered into the database by trained abstractors. For this study, we
Results
The study cohort consisted of 9336 term births; 47.4% of the pregnancies were delivered between 37-39 weeks’ gestation; 47.2% of the pregnancies were delivered at 40-41 weeks’ gestation, and 5.4% of the pregnancies were delivered at ≥42 weeks. Characteristics that were associated with longer gestation at term were white race/ethnicity, lower parity, higher weight gain, and private insurance. Asian women were less likely to progress past 40 weeks’ gestation, compared with other groups (Table 1).
Comment
In this cohort of women who delivered at ≥37 weeks’ gestation, we found that higher prepregnancy BMI was associated with longer gestation at term and higher risk of postterm pregnancy. Not only are overweight and obese women at increased risk of prolonged pregnancy, but underweight women are at a slightly decreased risk, compared with women with a normal prepregnancy BMI.
Our findings are consistent with those of Usha Kiran et al,10 who found that obese women were more likely to have a postterm
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Supported by grant HD01262 from the National Institute of Child Health and Human Development.
Cite this article as: Stotland NE, Washington AE, Caughey AB. Prepregnancy body mass index and the length of gestation at term. Am J Obstet Gynecol 2007;197:378.e1-378.e5.