Maternal and Neonatal Outcomes in Obese Women Who Lose Weight During Pregnancy

CM Cox Bauer; KA Bernhard; DM Greer; DC Merrill


J Perinatol. 2016;36(4):278-283. 

In This Article


In total, 17 244 births were identified, 6510 births with incomplete records were excluded from the study and 4105 (63%) of the excluded birth records were missing smoking status. Examination of the full study population (N=10 734) revealed patterns in patient distribution and maternal characteristics across weight change categories (Table 1). Specifically, women were distributed across categories in a negatively skewed pattern, with WtL containing 8% of all cases and WtGE alone containing >56% of all cases. The average overall change in weight among women with obesity was 24.02 pounds (95% CI 23.68 to 24.35). Across categories, the average change in weight ranged from a loss of 7.21 pounds (95% CI: −7.92 to −6.50) in WtL to weight gains of 6.10 pounds (95% CI: 5.95 to 6.25) in WtM, 15.97 pounds (95% CI: 15.86 to 16.09) in WtGA and 35.92 pounds (95% CI: 35.61 to 36.23) in WtGE. Differences were observed in maternal age (F=4.51, P<0.01), race/ethnicity (X 2=28.81, df=9; P<0.01) and BMI (F=163.79, P<0.01). Women who maintained weight during pregnancy were older than those in both WtL and WtGE categories. Racial/ethnic distributions suggested increased and decreased prevalence of weight gain in white and black women, respectively. A pattern of increasing weight gain with lower BMI was revealed. Finally, prevalence of chronic hypertension (X 2=13.12, df=3; P<0.01) and smoking behavior (X 2=13.21, df=3; P<0.01) was the greatest in WtM and WtL, respectively.

Within the matched populations, models revealed statistically significant associations between pregnancy weight change and several of the maternal and neonatal outcomes studied (Table 2 and Table 3). Compared with IOM recommendations (WtGA), women who lost weight had a mean decreased infant birth weight of 63 g, twofold greater risk of low birth weight infants and a mean decreased estimated blood loss of 30 ml. Women who gained excessive weight had over two times greater risk of gestational hypertension or preeclampsia, a mean increased infant birth weight of 134 g, four times greater risk of macrosomia and a mean decreased 5-min APGAR score of 0.09.

Several outcomes that exhibited statistically significant associations with maternal weight change did so through gradual change across the four weight change categories (Table 2 and Table 3). For instance, with increasing weight gain (from WtL to WtGE), we observed 1.40 times (95% CI: 1.12 to 1.77) greater odds of cesarean delivery, a mean increased gestational age of 1.31 days (95% CI: 0.02 to 2.61; P=0.04), a mean increased infant birth weight of 197 g (95% CI: 149 to 245; P<0.01) and a mean increased estimated blood loss of 47 ml (95% CI: 24 to 71; P<0.01). Although not demonstrating significant unidirectional change across all weight change categories, the odds of small-for-gestational age were 1.83 times (95% CI: 1.24 to 2.70) greater for women who lost than gained excessive weight.

Finally, no statistical evidence was found for difference among weight change categories in the model of preterm birth, despite the numerically observable trend of decreasing prevalence with increasing weight gain (Table 2 and Table 3). In addition, neither statistically significant associations nor observable patterns were detected across weight change categories for the outcomes of gestational diabetes, NICU admission, low 5-min APGAR (Table 3), umbilical cord pH (F=1.30, P=0.2727) and low cord pH (M 2 =0.9098, df=1, P=0.3402).