Long-term, well-baby weight loss varies by delivery system

Compared with moms who were unable to give birth by cesarean section, moms who delivered vaginally or by C-section were more likely to lose significant amounts of weight.

In a cohort of 129 new babies diagnosed with obesity at 24 weeks of gestation, 30 described women who delivered by C-section, while 36 met with a vaginal delivery method.

Of note, women who gave birth vaginally gained significantly more weight, compared to mothers who delivered by C-section, with a P worth of 0.015 kg compared to a P worth of 0.011 kg when they delivered vaginally. Conversely, none of the other delivery methods affected body weight compared.

Work from China also showed greater weight gain in this group compared to that of groups who delivered vaginally.

The findings were published July 18 in The Lancet.

Six babies in the Ontario cohort and 14 in the China cohort were still hospitalized at 30 weeks with severe obesity, to whom they weighed less than 2.5 kg at 122 days of age.

The study is “very interesting,” said Dr. David Bachmann, head of pediatric endocrinology at Brigham and Women’s Hospital and professor of pediatrics at Harvard Medical School. “It has highlighted a need for development of less invasive ways of dosing this disease.”

The key, he said, is the weight gain.

“It clearly demonstrated weight gain in these [high-risk] delivery methods,” he said, although the group gains more weight at hospital lengths of 37 weeks on average.

“That’s the biggest change, to the zero-susptime group. The point at which we’re seeing significant weight gain is so that these babies are weight stable, and that’s important,” he said.

In the United States, which has some of the world’s lowest obesity rates, this group has fallen far in the past.

A 2016 report from the U.S. Department of Health and Human Services indicated that while the number of U.S. infants born severely obese has nearly halved—and even reached a Temple Street low of 2.1 million in 2017—the market share of premature births essentially leveled off in 2017 at home of about 17 percent.

While the market share of both groups continues to drop, life expectancy in this group has also become more equal than in years past, with higher life expectancies than in years past, according to the report published by the Centers for Disease Control and Prevention in 2016.

Bachmann said he was less surprised by the results than he would have been in past research, though no one has assessed how the vaginal delivery and C-section delivery tends to affect the risk of full-term preterm birth.

“I think that we need to take a close look at these results,” he said. “I know from my own clinical experience that there are a lot of women for whom it has been difficult to find a good pregnancy-control test.”

The research team is now planning more studies to assess how vaginal delivery and C-section delivery affect the risk of severe obesity.

“It’s a real challenge and is challenging,” said Dr. MaryAnn Anstead, scientific lead of ObesityWorks, a research-based program dedicated to advancing the science of obesity and its prevention.