Pre-pregnancy overweight status between successive pregnancies and pregnancy outcomes.

Objective: The two objectives of this study were to (1) examine factors associated with changes in pre-pregnancy overweight to pre-pregnancy normal/underweight or obese Body Mass Index (BMI) in the subsequent pregnancy, and (2) assess select pregnancy and newborn outcomes associated with changes in pre-pregnancy BMI.

Methods: Birth certificates from 1995-2004 for residents of Kansas City, Missouri, were used to identify overweight nulliparous women who had a singleton birth and subsequently a second singleton birth. Maternal factors associated with changes in BMI between pregnancies were determined. Hypertension in pregnancy, preterm birth, emergency cesarean section, small-for-gestational age, and large-for-gestational age outcomes were examined.

Results: At second pregnancy, 55% of the women remained overweight, 33% were obese, and 12% had normal/underweight BMIs. The upward shift in BMI was associated with being unmarried and having a birth interval of 18 or more months, while the downward shift was associated with gestational weight gain. Of the five outcomes variables, only emergency cesarean section was significantly associated with an upward shift in BMI.

Conclusions: Clinical interventions for pre-pregnancy overweight women should focus on appropriate weight gain during pregnancy and motivators for loss of pregnancy-related weight during the postpartum period.