Pregnant woman eating pickles

(© Andrii Zastrozhnov -

PHILADELPHIA — There’s a dire new warning for women who gain excessive weight during pregnancy. Researchers from the University of Pennsylvania School of Medicine reveal that extreme weight gain during pregnancy displays a link to higher risks for heart disease and diabetes.

Scientists are expressing hope that this research will lead to increased efforts to support pregnant individuals in achieving healthy weight gain.

“We hope that this work leads to greater efforts to identify new, effective, and safe ways to support pregnant people in achieving a healthy weight gain,” says study lead author Dr. Stefanie Hinkle, an assistant professor of Epidemiology and Obstetrics and Gynecology at Penn, in a university release. “We showed that gaining weight during pregnancy within the current guidelines may protect against possible negative impacts much later in life, and this builds upon evidence of the short-term benefits for both maternal health and the health of the baby.”

The research builds upon the investigators’ previous studies, which established links between pregnancy complications and elevated mortality rates in the subsequent years. For this analysis, researchers examined data from the Collaborative Perinatal Project, which collected information from a racially diverse group of individuals who gave birth in the 1950s or 1960s. These records were then linked to mortality data extending through 2016, creating a timeline of almost 50 years.

The analysis encompassed data from over 45,000 individuals, including their body mass indices (BMI) and weight changes during pregnancy. Researchers compared these findings with contemporary recommendations for pregnancy weight gain, which are based on a person’s pre-pregnancy weight. These guidelines, established in 2009, recommend a weight gain range of 28 to 40 pounds for “underweight” individuals by BMI standards and 11 to 20 pounds for those categorized as “obese.”

Pregnant woman eating chocolate
Pregnant woman eating chocolate (Photo by ORION PRODUCTION on Shutterstock)

Nearly half of pregnant individuals today exceed these recommended weight gain ranges. Approximately 39 percent of the individuals in the study cohort had passed away by 2016, and the mortality rate was found to increase in correlation with pre-pregnancy BMI. Individuals with lower BMIs before pregnancy had lower mortality rates than those with higher BMIs.

Among individuals categorized as “underweight” before pregnancy but gained more weight than recommended, there was an 84 percent increased risk of death related to heart disease. For those classified as “normal” weight before pregnancy (about two-thirds of the cohort), exceeding the recommended weight gain resulted in a nine percent increase in all-cause mortality and a 20-percent increased risk of death from heart disease. Those classified as “overweight” before pregnancy had a 12-percent increased risk of death if they exceeded the recommended weight gain, with a corresponding 12-percent increased risk of diabetes-related death.

The study found no association between excessive weight gain during pregnancy and subsequent mortality among individuals in the obese range. While this aspect wasn’t the primary focus of the study, Dr. Hinkle suggested that this group’s already elevated mortality rates may have contributed to this finding.

Weight gain during pregnancy is influenced by a complex interplay of factors, including access to healthcare, nutrition, and stress. However, now that researchers have uncovered the long-term risks associated with unhealthy weight gain, they aim to explore these factors more comprehensively in the hope of addressing the issue.

“We are committed to delving deeper into the various factors that can affect pregnant individuals’ ability to achieve healthy weight gain during pregnancy,” notes Dr. Hinkle. “Our team is dedicated to exploring the social, structural, biological, and individual aspects that play a role in this process.”

The study is published in the journal The Lancet.

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