Newswise — SILVER SPRING, MD – New research provides the first glimpse of weight-gain guidance for pregnant women with various classes of obesity based on body mass index (BMI), and suggests that they not gain any weight until mid-pregnancy or later. The study by Jennifer Hutcheon, PhD, and colleagues conducted at Magee-Womens Hospital in Pittsburgh, PA, is the first to provide reference values for pregnancy weight gain in women with class II obesity (BMI 35-39.9) and class III obesity (BMI ≥40). The research is published in the March issue of Obesity.

“Research shows that pregnant women with obesity are at increased risk of pregnancy complications, including gestational diabetes mellitus, hypertension, preeclampsia, cesarean delivery and postpartum weight retention,” says lead author Dr. Hutcheon, Assistant Professor for the Department of Obstetrics & Gynecology at the University of British Columbia. “Similarly, children born to pregnant women with obesity face higher risks of prematurity, stillbirth, congenital anomalies, macrosomia with possible birth injury and childhood obesity. These known risks reinforce the need to closely monitor weight gain during pregnancy for women with obesity, which reduces risks and can lead to better outcomes.”

Current gestational weight-gain guidelines by the Institute of Medicine do not recommend lower targets for women with more severe degrees of obesity, citing a lack of sufficient data regarding short-term and long-term maternal and newborn outcomes. This new study provides data that have the potential to aid in the development of national reference values for optimal gestational weight gain for pregnancy among women who have higher classes of obesity including class II and class III obesity. Further, the scientists recommend more research before setting guidelines or targets on a national scale.

“Monitoring weight gain during pregnancy is key for optimal outcomes, and this is the first time we’ve had a glimpse of reference points for women with class II and class III obesity,” continues Dr. Hutcheon. “With these data, we are a step closer to developing a more comprehensive understanding of safe and healthy levels of weight gain for women with different classes of obesity during pregnancy.”

To conduct the study, researchers collected serial weight measurements from more than 4,000 women with pre-pregnancy BMI ≥25, placing them in the category of overweight or obesity, in a large women’s hospital in Pennsylvania from 1998 – 2010. The women all had uncomplicated full-term pregnancies and deliveries.

Based on their findings, the researchers led by Hutcheon suggest that women with obesity not gain any weight until mid-pregnancy or later, and break down their recommendations by class I obesity (BMI ≥30), class II obesity (BMI 35-39.9) and class III obesity (BMI ≥40).

“These new data are an important first step in determining the amount of weight gain (or loss) that is appropriate for women who enter pregnancy with obesity – data which are sorely needed by obstetric providers to better serve their patients,” says Sharon Herring, MD, MPH, an expert in this area who is a member of The Obesity Society and Assistant Professor at Temple University. “More studies that explore both the short- and long-term infant and maternal outcomes of these findings are needed, in nationally representative samples, to optimize clinical care.”

Clinicians looking to provide additional support to patients can view TOS’s Clinician Directory to find health care providers certified in obesity treatment. Clinicians should also review, a campaign from TOS, for additional obesity resources and tools.

Read the full article in Obesity, a scientific journal published by The Obesity Society, here.

# # #

This press release can be published in full or in part with attribution to The Obesity Society.

About The Obesity SocietyThe Obesity Society (TOS) is the leading professional society dedicated to better understanding, preventing and treating obesity. Through research, education and advocacy, TOS is committed to improving the lives of those affected by the disease. For more information visit: Connect with us on social media: Facebook, Twitter and LinkedIn.