Weight loss may not improve fertility in women with obesity, yet it confers other benefits
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Among women with obesity and unexplained infertility, weight loss before infertility treatment did not increase the likelihood of having a healthy live birth, according to findings published in PLoS Medicine.
However, researchers said that weight loss may confer other health benefits for women with obesity who are trying to conceive. Their study revealed improvements in metabolic health, including a decrease in the incidence of metabolic syndrome, among women who were enrolled in an intensive lifestyle intervention compared with those who were enrolled in a standard exercise intervention.
“We can achieve significant weight loss and improvement in cardiometabolic health through an intensive lifestyle intervention in women who are obese with unexplained infertility in a reasonably short time period of 16 weeks,” Richard S. Legro, MD, FACOG, a professor in the department of obstetrics and gynecology and public health sciences at Penn State University College of Medicine, and colleagues wrote.
Weight loss over a short time period “improves multiple metabolic markers associated with long-term risk for diabetes and heart disease,” Legro told Healio.
In an open-label, randomized controlled trial that was conducted from July 2015 to July 2018, Legro and colleagues randomly assigned 379 women with obesity (BMI 30 kg/m²) and unexplained infertility into a 1:1 ratio to participate in the intensive lifestyle intervention or standard exercise intervention for 16 weeks. The mean age of the women was about 32 years. Following the intervention, the women received infertility therapy consisting of three cycles of ovarian stimulation/intrauterine insemination.
In the intensive intervention group, 188 women underwent increased physical activity and targeted weight loss (7%) through meal replacements and orlistat administration. In the standard exercise group, 191 women underwent increased physical activity alone without targeted weight loss. However, during the study period, 40 women dropped out of the standard exercise group and 31 women dropped out of the intensive intervention group.
Metabolic improvements with weight loss
Overall, there was no significant difference in the incidence of healthy live births in the standard exercise group (15.2%) and the intensive intervention group (12.2%; RR = 0.81; 95% CI, 0.48-1.34), according to the researchers. Women receiving the intensive intervention experienced significant weight loss compared with the standard group (6.6% vs 0.3%; P < .001). These women experienced improvements in metabolic and reproductive health parameters, including decreased BP, waist circumference, total testosterone, insulin, glycohemoglobin, leptin, high-sensitivity C-reactive protein and triglycerides and increased sex hormone–binding globulin and adiponectin levels. Legro and colleagues also observed that the incidence of metabolic syndrome decreased significantly among women in the intensive intervention group (P = .003), yet gastrointestinal adverse events were more common. Also, there was an insignificant increase in miscarriages during the first trimester in the intensive intervention group (33.3%) compared with the standard care group (23.7%; 95% CI, 0.79-2.5).
Additional research needed
“Our findings directly impact current standards of clinical care, where women who are obese with unexplained infertility are to our knowledge routinely counseled to lose weight prior to initiation of infertility treatment,” Legro and colleagues wrote.
Based on the findings, “patients may forgo a long-term benefit of weight loss if they see no short-term benefit in achieving it, and actually may experience short-term harm through increased pregnancy loss with weight loss or just a waste of time in pursuing weight loss while the sands of the fertility hourglass are running out,” Legro said.
He advised that, until research can prove demonstrable benefits related to fertility, physicians “should stop telling women” with obesity and infertility to lose weight prior to pregnancy.
References:
Legro RS, et al. PLoS Med. 2022;doi:10.1371/journal.pmed.1003883.
Weight loss before infertility treatment may not increase healthy births for women with obesity. https://pennstatehealthnews.org/2022/01/weight-loss-before-infertility-treatment-may-not-increase-healthy-births-for-women-with-obesity/. Published Jan. 18, 2022. Accessed Jan. 20, 2022.