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Study: For Obese Women Trying to Conceive, Infertility Treatment Is Best - Weight loss failed to hel

A lifestyle intervention for obese women struggling with infertility did not improve their chances of getting pregnant compared with a control group treated only for infertility, a small Dutch randomized trial found.

An intent-to-treat analysis found that 24 months after randomization, a smaller portion of obese women with a BMI >29 who received lifestyle intervention had a vaginal birth of a healthy infant compared with a control group who received fertility treatments (27.1% vs 35.2%, respectively; relative risk 0.77, 95% CI 0.60-0.99), reported Meike A.Q. Mutsaerts, MD, of University of Groningen in the Netherlands, and colleagues.

There was also a statistically significant difference in the amount of time to conception resulting in a live birth in the 576-person trial. The intervention group had a longer mean time to pregnancy (8.8 months versus 5.2 months in control group, P=0.04), though the difference in mean time to pregnancy resulting in healthy vaginal birth did not quite reach significance (7.2 months versus 5.2 months, P=0.06).

Writing in the New England Journal of Medicine, Mutsaerts and colleagues said that while weight loss of 5%-10% of body weight is a first step in treating infertility in obese, infertile women, "large randomized controlled trials assessing the effectiveness of lifestyle-intervention programs to support these guidelines are lacking."

Not surprisingly, secondary outcomes of the trial showed that while it had no impact on pregnancy outcomes, the intervention group did lose more weight. The intervention group lost significantly more weight than the control group (mean 4.4 ±5.8 kg versus 1.1 ±4.3 kg, respectively, P<0.001). In the first 6 months, more than a third (37.7%) of the intervention group lost 5% or more of their baseline body weight.

"A more intensive program or one involving better strategies to enhance adherence might have resulted in more weight loss, but it is unknown whether more weight loss would have led to a higher birth rate than the rate in our trial," the authors wrote, adding that excessive weight loss in a short period of time has been associated with increased risk of adverse pregnancy outcomes and may also impede the effectiveness of assisted reproductive technology (ART) treatments.

However, weight loss may have been associated with the ability of the intervention group to spontaneously conceive. Compared with the control group, a higher portion of women in the intervention group had a "natural" conception (26.1% versus 16.2%, RR 1.61). The number of infertility treatment cycles was also lower among the intervention group versus controls (679 versus 1,097, respectively).

There were no significant differences in adverse events between groups, including neonatal outcomes, mean birth weight, or the number of small-for-gestational-age infants.

Mutsaerts and colleagues randomized 289 women to an intervention group and 287 to a control group. Eligible participants were infertile women ages 18-39 (mean age 30 years). The intervention group was comprised of a 6-month lifestyle intervention with the goal of losing 5% to 10% of the woman's baseline body weight. Women discontinued the intervention treatment if they became pregnant, but if they were not pregnant after 6 months, they were then treated according to Dutch infertility guidelines. The control patients were treated according to Dutch infertility guidelines, with ovulation-inducing drugs and later, intrauterine insemination or IVF/ICSI. A healthy vaginal birth was defined as an infant born >37 weeks with no congenital anomalies.

Limitations to the study included that participants were not blinded to the type of infertility treatment prior to randomization. In addition, women in the intervention group were only allowed to access fertility treatment for 18 months compared with 24 months for the control group, which may have contributed to an increased time to pregnancy and lower birth rates.

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