Effects of Gestational Weight Gain on Delivery Outcomes in an Obese, Low-Income Population

Allison Archer Sellner, MD; Abigail Hook Garbarino, MD, DiMiao, PhD; Lisa Marie Hollier, MD, MPH; Bani Maheshwari Ratan, MD


South Med J. 2021;114(11):686-691. 

In This Article

Abstract and Introduction


Objective: To examine the effects of weight gain/loss on delivery outcomes stratified by class of obesity in an obese, low-income, predominantly minority population.

Methods: A retrospective review of a cohort of 1428 women receiving care at a large Medicaid clinic from 2013 to 2016 with pregravid body mass index ≥30 was conducted. Multinomial logistic regression analysis was used to compare differences in gestational weight change to the primary outcomes of birth-weight percentile and delivery type and secondary outcomes of preterm delivery, preterm labor, gestational diabetes mellitus, and gestational hypertension.

Results: Obesity class 1 patients who lost weight were more likely to have a small-for-gestational-age (SGA) infant compared with those who had recommended weight gain. Obesity classes 2 and 3 patients had no statistically significant increase in SGA infants with weight loss or weight gain below current recommendations. Obesity classes 1 and 2 patients with weight loss had a statistically significant increase in both preterm delivery and preterm labor; however, class 3 patients did not. Obesity class 3 patients who lost weight were significantly more likely to have gestational diabetes mellitus.

Conclusions: Obesity class 3 women may benefit from less weight gain than current recommendations without increasing their risk of SGA infants or preterm birth, especially if gestational diabetes mellitus is present.


Obesity is an increasing public health concern, both in the general population and in obstetrics.[1,2] According to the National Health and Nutrition Examination Survey (2015–2016), 68% of women are considered to be overweight (body mass index [BMI] ≥25) or obese (BMI ≥30), with 9.7% of women considered extremely obese (BMI ≥40). From 1999 to 2016, the prevalence of obesity among reproductive-age women (ages 20–39) has increased from 28.3% to 36.5%.[3]

In regard to pregnancy, obese women experience greater risks of medical and surgical comorbidities, including diabetes mellitus, hypertension, sleep apnea, need for cesarean delivery, and postpartum complications. There also are increased fetal risks, including congenital anomalies, macrosomia, and stillbirth.[4] In 2009, the National Academy of Medicine (known then as the Institute of Medicine) amended their guidelines for weight gain in pregnancy, recommending an 11- to 20-lb weight gain for all women with BMI ≥30.[5] The National Academy of Medicine cited limited data to further stratify these recommendations based on level of obesity, with most of the data used in the report coming from women with class 1 obesity (BMI 30.0–34.9).[6]

The National Academy of Medicine further reports that 46% of women gain weight in excess of current recommendations.[5] Across all BMI categories, pregnancy is associated with permanent weight gain.[7] Excessive weight gain during pregnancy and a failure to subsequently lose this weight postpartum are important predictors of lifelong obesity and the many risks associated with an elevated BMI, including diabetes mellitus, heart disease, certain types of cancer, and premature death.[8] In addition, a vicious cycle is set up of maternal obesity contributing to childhood obesity and metabolic syndromes in the futures of the children of obese women.[9] Although the National Academy of Medicine recommendations maintain a focus on decreasing the risk of fetal growth restriction and small-for-gestational-age (SGA) infants, the long-term ramifications of unnecessary weight gain in obese reproductive-age women are not fully addressed.

Emerging research has conflicting evidence regarding the risks and benefits of limiting weight gain during pregnancy. Studies looking at pregnancy weight gain below the National Academy of Medicine recommendations in overweight and obese women found lower rates of adverse pregnancy outcomes, including preeclampsia, cesarean delivery, and large-for-gestational-age (LGA) birth, with varying results for SGA risk and preterm birth with more restrictive weight gains, weight maintenance, or weight loss.[10–17] Several studies are limited because they do not control for confounding factors such as cigarette smoking and socioeconomic status or because they stratify their results based on obesity class.

Modifying the National Academy of Medicine guidelines and stratifying recommendations by obesity class may strike a better balance between maternal and neonatal outcomes and help to mitigate the long-term effects of excessive weight gain in pregnancy. The purpose of our study was to add to the body of research by further examining the effects of weight gain/loss on delivery outcomes in relation to class of obesity in a predominantly low-income and minority population.