The association between gestational weight gain z-score and stillbirth: a case-control study

• Type of Material: Article
• Authors: CM Pickens, Emory University; Carol Hogue, Emory University; Penelope Howards, Emory University; Michael Kramer, Emory University; Martina Badell, Emory University; DJ Dudley, University of Virginia; RM Silver, University of Utah; RL Goldenberg, Columbia University; H Pinar, Brown University; Barbara Stoll, Emory University
• Language: English
• Date: 2019-11-29
• Publisher: BMC
• Publication Version: Final Published Version
• Copyright Statement: © 2019 The Author(s).
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1186/s12884-019-2595-x
• Title of Journal or Parent Work: BMC Pregnancy and Childbirth
• Volume: 19
• Issue: 1
• Start Page: 451
• End Page: 451
• Grant/Funding Information: Maternal and Child Health Bureau, Health Resources and Services Administration; Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health; Additional stipend support was provided by Laney Graduate School, Emory University.
• Keywords: DEATH; Gestational weight gain; CHARTS; Science & Technology; RISK; BIAS; Obstetrics & Gynecology; BIRTH; OBESITY; PREGNANCY; Fetal death; OVERWEIGHT; Life Sciences & Biomedicine; AGE; Stillbirth; Obesity; MATERNAL WEIGHT
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Obstetrics and Gynecology; Health Sciences, Pathology

Abstract

Background: There is limited information on potentially modifiable risk factors for stillbirth, such as gestational weight gain (GWG). Our purpose was to explore the association between GWG and stillbirth using the GWG z-score. Methods: We analyzed 479 stillbirths and 1601 live births from the Stillbirth Collaborative Research Network case-control study. Women with triplets or monochorionic twins were excluded from analysis. We evaluated the association between GWG z-score (modeled as a restricted cubic spline with knots at the 5th, 50th, and 95th percentiles) and stillbirth using multivariable logistic regression with generalized estimating equations, adjusting for pre - pregnancy body mass index (BMI) and other confounders. In addition, we conducted analyses stratified by pre - pregnancy BMI category (normal weight, overweight, obese). Results: Mean GWG was 18.95 (SD 17.6) lb. among mothers of stillbirths and 30.89 (SD 13.3) lb. among mothers of live births; mean GWG z-score was - 0.39 (SD 1.5) among mothers of cases and - 0.17 (SD 0.9) among control mothers. In adjusted analyses, the odds of stillbirth were elevated for women with very low GWG z-scores (e.g., adjusted odds ratio (aOR) and 95% Confidence Interval (CI) for z-score - 1.5 SD versus 0 SD: 1.52 (1.30, 1.78); aOR (95% CI) for z-score - 2.5 SD versus 0 SD: 2.36 (1.74, 3.20)). Results differed slightly by pre - pregnancy BMI. The odds of stillbirth were slightly elevated among women with overweight BMI and GWG z-scores ≥1 SD (e.g., aOR (95% CI) for z-score of 1.5 SD versus 0 SD: 1.84 (0.97, 3.50)). Conclusions: GWG z-scores below - 1.5 SD are associated with increased odds of stillbirth.