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


Of the total of 1428 women with a BMI >30 who obtained prenatal care between September 2013 and August 2017, 1184 initiated prenatal care before 20 weeks. Of those patients, 254 were excluded from this study resulting from miscarriage, termination, ectopic, and being lost to follow-up. Of the remaining 930 patients, 18 were excluded because of twin pregnancies and 22 because of their status as smokers. This left a total of 890 pregnancy episodes that were used for this study. Mean GA at the initial prenatal visit was 11.6 ± 3.8 weeks and mean GA at delivery was 38.6 ± 2.3 weeks.

Supplemental Digital Content Appendix 1 (http://links.lww.com/SMJ/A246) shows demographic data stratified by obesity class. The study population predominantly comprised minorities, with 93% either Hispanic or African American. Of note, a significantly greater percentage of African American patients made up the obesity class 3 group (41%) than class 1 (23%) or class 2 (29%). The majority of patients were between the ages of 21 and 30 (61%), had a spouse or significant other (90%), were multiparous (77%), and participated in traditional prenatal care (77%). Class 3 obese patients were more likely to have a nutrition consult, have gestational hypertension or gestational diabetes mellitus, and gain less than the recommended amount of weight during pregnancy. Supplemental Digital Content Appendix 2 (http://links.lww.com/SMJ/A246) reviews obstetrics outcome data stratified by obesity class. There was no significant difference in fetal size or preterm delivery across obesity classes. Obesity classes 2 and 3 patients were more likely to undergo a cesarean section, and class 3 patients also were more likely to develop gestational diabetes mellitus.

Table 1 and Table 2 show univariate logistical regression analysis of fetal size outcomes and delivery type stratified by obesity class and weight change during pregnancy. Class 1 patients who lost weight were significantly more likely to have an SGA fetus, whereas class 1 patients who had inadequate weight gain had a trend toward having an SGA fetus. There was no significant difference in SGA seen in class 2 or 3 patients who lost weight or gained inadequate weight. Across all of the classes, there also was no significant difference in the vaginal delivery rate based on weight change during pregnancy; however, class 1 patients with weight loss had a significant increase in scheduled cesarean section, whereas class 2 patients with excessive weight gain had a significant increase in cesarean sections performed during labor. Table 3 shows a univariate analysis of preterm labor and preterm birth stratified by obesity class and weight change. Class 2 patients who lost weight during pregnancy were at increased risk for both preterm birth and preterm labor.

All of the factors that were found to be significant in univariate analysis were controlled for in the multivariable regression analysis (Table 4). Weight loss remained significantly associated with SGA in obesity class 1 pregnancies, but not in class 2 and 3 pregnancies. Weight loss also was significantly related to preterm birth and preterm labor in class 1 and class 2 pregnancies. Obesity class 3 patients who lost weight were more likely to receive a diagnosis of gestational diabetes mellitus. In the combined analysis of all of the obesity classes for those women with weight loss, there were significant increases in risk for SGA, preterm labor, and preterm delivery with a decrease in the risk of cesarean section during labor.