Most existing research on gestational weight gain and pregnancy outcomes has not accounted for timing of weight gain. The area under the weight gain curve (AUC) provides a single measure that incorporates both timing of weight gain and total amount gained. This study evaluated predictors and outcomes associated with second- and third-trimester weight gain AUC from the second and third trimester using time-to-event analysis to account for the correlation between gestional weight gain and gestational duration.
Our prospective cohort study used data from the LifeCodes study at Brigham and Women’s Hospital. Maternal weights were available from all prenatal and study visits. We used log–poisson models with empirical variance estimation to identify predictors of total AUC from 14 weeks to delivery and Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association between AUC quintile and adverse pregnancy outcomes.
Compared to the middle quintile, the highest quintile of accumulated pound–days was associated with a decreased hazard of spontaneous preterm birth among multigravid women [Hazard Ratio (HR): 0.44, 95% Confidence Interval (CI) 0.23, 0.84], a decreased hazard of small-for-gestational age (SGA) births (HR 0.65, 95% CI 0.45, 0.92) overall and an increased hazard of large for gestational age (LGA) births among normal and underweight women (HR 3.21, 95% CI 1.50, 6.89)
In our study, a pattern of gestational weight gain characterized by more rapid gains earlier in pregnancy was associated with improved pregnancy outcomes in some subgroups of pregnant women.
1Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts
2Department of Global Health and Population, Harvard TH Chan School of Public Health, Boston, Massachusetts
3Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, Massachusetts
4Department of Nutrition, Harvard TH Chan School of Public Health, Boston, Massachusetts.
5Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts
Conflicts of interest: None declared
Sources of funding : This study was supported by T32 HD052458 (Boston University Reproductive, Perinatal and Pediatric Epidemiology training program) from the National Institutes of Health.
Correspondence and requests for data/code: Anne Marie Darling, Boston University School of Public Health, Department of Epidemiology, 715 Albany Street, Boston, MA 02118, email@example.com, elephone: 617-638-7775