Effects of Women's Weight Changes on Adverse Outcomes in a Second Pregnancy

To estimate the effects of women's weight changes in four sequential perinatal periods across first and second pregnancies (pregravid, first gestation, interpregnancy, second gestation) on adverse maternal and neonatal outcomes in the second pregnancy while accounting for interdependencies in weight across the four periods (Aim 1) and to test the influence of the sequential path of weight changes through the four perinatal periods of risk on maternal and neonatal outcomes in the second pregnancy (Aim 2).

Secondary data analysis.

Thirty-one Wisconsin hospitals.

Women with 24,795 linked records from first and second births from 2006 through 2013.

We used a fully recursive system of linear and logistic regression equations to examine the relationships among weight changes in the four perinatal periods with maternal (gestational diabetes mellitus, gestational hypertension, cesarean birth) and neonatal (macrosomia, small for gestational age, large for gestational age, low birth weight, congenital anomalies, and perinatal death) adverse outcomes in the second pregnancy.

Pregravid weight was weakly and inconsistently associated with weight changes in subsequent periods. Each 5-kg incremental weight change in the first pregnancy, interpregnancy, and second pregnancy contributed to a 0.75- to 5-kg weight change in subsequent periods, 9% to 25% change in risk for adverse maternal outcomes, and 8% to 47% change in risk for adverse neonatal outcomes in the second pregnancy. Fluctuations in weight across pregnancies and associations with outcomes were strongest among normal-weight and overweight women.

Weight changes across two pregnancies affected maternal and neonatal outcomes in the second pregnancy in all body mass index categories; the larger weight fluctuations observed in normal and overweight women were associated with greater risk of adverse outcomes. Attention to pregnancy weight during and between pregnancies is important for targeted weight counseling to reduce risks in subsequent pregnancies.