Clinical Edge

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Women with obesity need not boost calories during pregnancy

Key clinical point: Women with obesity should not increase their daily calorie intake during pregnancy.

Major finding: Women with obesity achieved recommended weight gain during pregnancy with an average 125 kcal/day deficit from their energy expenditure.

Study details: MomEE, a single-center, prospective study of 54 pregnant women with obesity intensively followed during weeks 13-37 of pregnancy.

Disclosures: The National Institutes of Health and the Clinical Research Cores at Pennington Biomedical Research Center funded the study. Dr. Redman had no disclosures.


Redman LM et al. Obesity Week 2019, Abstract T-OR-2079.


The results reported by Dr. Redman from the MomEE study showed that women with obesity need not ingest surplus calories to gain weight during pregnancy. The findings indicate that pregnant women efficiently convert a portion of their accumulated fat mass to fat-free mass in the form of the fetus, uterus, blood volume, and other tissue. A deficit of about approximately 100 kcal/day effectively kept weight gain within the 11- to 20-pound target recommended by the Institute of Medicine in 2009.

But the weight gains recommended for women with obesity may be too high. The desire of the writers of the IOM recommendation to avoid negative perinatal outcomes for infants may instead lead to negative maternal outcomes, such as preeclampsia, gestational hypertension, and need for cesarean birth. Gestational weight gains below what the IOM recommended for women with obesity may be able to serve present-day standards and work better for these pregnant women by reducing their morbidity risk. Future studies should take into careful account overall nutrient values rather than just calorie intake, as well as physical activity.

The MomEE results showed that a striking two-thirds of women with obesity gained an excess of weight during pregnancy, beyond the 2009 recommendations. This finding highlights the need to identify strategies that can prevent excessive weight gain. Furthermore, results from several studies and systematic reviews suggest that the IOM recommendation for weight gain during pregnancy is too high for women with obesity, especially those with class II-III obesity, with a body mass index of 35 kg/m2 or greater. In my opinion, an appropriate weight-gain target to replace the current, blanket recommendation of 11-20 pounds gained for all women with obesity is a target of 5-15 pounds gained for women with class I obesity, less than 10 pounds for class II obesity, and no change in prepregnancy weight for women with class III obesity.

Sarah S. Comstock, PhD, is a nutrition researcher at Michigan State University, East Lansing. She is an inventor named on three patents that involve nutrition. She made these comments in an editorial that accompanied the MomEE report (J Clin Invest. 2019;129[11]:4567-9).