Lifestyle Intervention Improves Fertility in Obese Women

Miriam E. Tucker

April 03, 2019

NEW ORLEANS — A low-intensity lifestyle intervention could help improve fertility in obese women who are having trouble conceiving, new research shows.

Findings from an 18-month randomized controlled trial comparing a lifestyle program with usual fertility treatment in infertile women with overweight/obesity were presented March 23 here at ENDO 2019: The Endocrine Society Annual Meeting by Matea Belan, a PhD student at Sherbrooke University, Quebec, Canada.

The intervention, which combined individual sessions with a nutritionist and kinesiologist every 6 weeks and 12 mandatory group sessions, significantly improved rates of both overall and spontaneous pregnancy. The intervention also improved the proportion of live births compared with controls, although this difference was not significant.

Most professional fertility societies recommend that obese women with infertility lose between 5% and 10% of their body weight with lifestyle modification to improve their chances of conceiving, based on data suggesting that obesity impairs fertility.

However, the only prior randomized controlled trial data of a weight loss intervention to improve fertility produced negative results at 6 months.

The current trial is different, Belan explained, in that it continued the intervention and followed women for up to 18 months or the end of pregnancy. Also, that prior trial used a very intensive intervention whereas the current study used a lower-intensity intervention but more frequent visits to reinforce the behaviors.

"We went with attainable goals to improve their nutritional and lifestyle habits slowly and gradually. We want them to maintain it over time rather than do something very fast that is not going to be maintained," Belan told Medscape Medical News.

Asked to comment, Licy L. Yanes Cardozo, MD, assistant professor of medicine at the University of Mississippi Medical Center, Jackson, told Medscape Medical News: "I just loved that paper...I was surprised with the impact. It wasn't just diet and exercise, but also motivation. That's the way to do it. What we do now in the clinic is tell people to go home and lose some weight."

"These patients had 12 or more sessions with the team. I think that made the difference. It was well done."

Both Overall and Spontaneous Pregnancy Rates Improved

The Obesity-Fertility Study randomized 130 women seeking fertility treatment who had a body mass index (BMI) ≥ 30 kg/m2 or who had polycystic ovary syndrome (PCOS) and a BMI ≥ 27 kg/m2. Those enrolled were an average age of 30 years and had a mean BMI of 40 kg/m2.

The 65 women randomized to the "Fit-for-Fertility" intervention did not receive any other fertility treatments for the first 6 months of the study but could receive them after that. The 65 controls underwent usual fertility treatments throughout. A total of 46 intervention and 52 control patients finished the 18-month study.

For the lifestyle intervention, investigators used motivational interviewing to determine patients' current lifestyle habits and ascertain what changes they were capable of making. They were asked to reduce their total caloric intake by about 500 calories/day but weren't asked to change their diets. They were also advised to increase physical activity by about 150 minutes/week.

"We wanted small changes, but maintained through time," Belan explained.  

At 6 months, the mean weight changes were –3.4% vs –0.89% for the intervention versus control groups (P = .003), waist circumference dropped by 2.9 cm vs 0.97 cm (P = .036), and percentage fat mass dropped by 1.3% vs 0.47%, respectively (P = .033).

"Although the differences don't seem large, the intervention group had significantly improved their anthropomorphic measures compared to controls," Belan noted.

The lifestyle intervention group also showed significant improvements in Health Eating Index scores (P = .001) and daily energy expenditure by metabolic equivalents (P = .040), and reduced the amount of time spent on sedentary activities (–6.48 vs 0.24 hours/week; P = .002). 

At 18 months, 60.8% of the intervention group had become pregnant compared with just 38.6% of controls (P = .021). And spontaneous pregnancies — that is, among those not using fertility treatments — almost tripled, occurring in 33.3% vs 12.3% (P = .009).

The primary outcome, live births at 18 months, did not significantly differ between the intervention and control groups (51.0% vs 36.8%; P = .139), but the difference — which was almost 40% higher in the intervention group — was "highly clinically significant," Belan said.

Some of the women had expressed concern that entering the study and postponing fertility treatment for 6 months if they were randomized to the intervention might adversely affect their ability to later conceive.

But that didn't appear to be the case, as pregnancy rates actually rose over time in the lifestyle intervention group, from 17.6% in the first 6 months up to 23.5% by 12-18 months, versus a drop from 17.6% to 5.3% for the controls.

Cardozo commented, "The weight loss wasn't that impressive, but there were impressive positive changes. So, there may be something independent of the weight loss."

She also pointed out that just cutting out two sugared sodas a day would come close to accomplishing the dietary goals for the intervention, noting, "That's not so difficult...it doesn't have to be dramatic. Reduce some calories, be more active. Now we have a study that shows if you do these [things], it improves your chances...We need to give patients the tools."

Belan and Cardozo have reported no relevant financial relationships.

ENDO 2019. Presented March 23, 2019. Abstract OR11-2.

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