Weight loss doesn't help pregnancy chances, study finds

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Women who are obese and struggling to become pregnant are often advised to lose weight, but a new study finds no fertility benefits from weight loss.

A randomized study of 379 women with obesity and unexplained infertility found that intensive lifestyle changes that shed pounds led to no better chances of pregnancy and healthy births than simply increasing physical activity without loss.

"We have known for decades that often have difficulty getting pregnant," said researcher Daniel J. Haisenleder, Ph.D., of the University of Virginia School of Medicine's Center for Research in Reproduction. "For this reason, many physicians advise weight loss prior to conception. However, there are few studies that have addressed the issue comparing a healthy lifestyle—i.e., exercise—vs. exercise plus weight loss."

Obesity and Pregnancy

The FIT-PLESE study, conducted at nine across the country, divided participants into two groups: Half the women dieted intensely using meal replacements, medications and increased physical activity. The other half simply increased their without trying to lose weight. After completing the programs, both groups received three rounds of standard infertility treatments.

Women in the weight-loss program ended up losing, on average, 7% of their body weight, while participants in the exercise-only group typically maintained their weights. But, in the end, there were no significant differences between the two groups in terms of the frequency of healthy births. In total, 23 of the 188 women who completed the 16-week intensive weight-loss program ended up giving birth; among the 191 who completed the exercise-only program, 29 gave birth.

The intensive dieting program did offer for the women who completed it, however. In addition to dropping pounds, they saw a major decrease in , a cluster of conditions that increase the risk for serious health problems such as diabetes, stroke and heart disease.

Based on their findings, Haisenleder and his collaborators conclude that the weight-loss program did not make women more fertile or improve birth outcomes compared with simply exercising. They note the health benefits of may not translate into better odds of getting pregnant.

"Weight loss improved metabolic health in these subjects. Unfortunately the changes seen did not improve fertility," Haisenleder said. "Infertility within this population remains an important health issue, and will require further studies to address the problem in the future."

The researchers have published their findings in the scientific journal PLOS Medicine.

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Weight loss before fertility treatment may not increase births for obese women

More information: Richard S. Legro et al, Effects of preconception lifestyle intervention in infertile women with obesity: The FIT-PLESE randomized controlled trial, PLOS Medicine (2022). DOI: 10.1371/journal.pmed.1003883
Journal information: PLoS Medicine

Citation: Weight loss doesn't help pregnancy chances, study finds (2022, March 14) retrieved 15 August 2022 from https://medicalxpress.com/news/2022-03-weight-loss-doesnt-pregnancy-chances.html
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