Weight Loss Boosts Natural Conception Chances Before IVF, Study Finds

Oxford-Led Study Shows Weight Loss Can Enhance Fertility Outcomes

Women with obesity who take part in structured weight loss programmes before starting IVF treatment are significantly more likely to conceive naturally, according to new research led by the University of Oxford. The study found that such women had a 47% higher chance of conceiving without assisted reproductive technology compared to those who received little or no support for weight loss.

Large-Scale Review Across 12 Trials

The findings come from a systematic review and meta-analysis of 12 international clinical trials, involving 1,921 women. Funded by the National Institute for Health and Care Research (NIHR), the research examined a variety of interventions — from dietary changes and exercise to weight loss medications.

Women in the intervention groups, on average, lost around 4 kilograms (9 pounds) more than those in the comparison groups.

Improved Overall Pregnancy Rates

In addition to improved rates of natural conception, the interventions also increased the likelihood of any pregnancy — natural or via IVF — by 21%. These results have significant implications for healthcare providers and policymakers, particularly as access to NHS-funded IVF in England is often restricted for women with a Body Mass Index (BMI) over 30.

Impact on Live Birth Still Uncertain

Despite promising signs, the researchers emphasized that more data is needed to confirm whether these weight loss efforts ultimately result in more live births. According to Associate Professor Nerys Astbury, many of the reviewed studies did not track pregnancies through to delivery, leaving a gap in the evidence for the most critical outcome — having a healthy baby.

Interestingly, when the researchers focused solely on low-energy meal replacement diets, which typically lead to greater weight loss, they observed an increase in live births — though this, too, requires confirmation through larger and higher-quality trials.

Policy Implications and Recommendations

Dr. Moscho Michalopoulou, co-author from Oxford’s Nuffield Department of Primary Care Health Sciences, noted that incorporating structured weight loss programmes into fertility services could both improve outcomes and reduce reliance on IVF.

Professor Astbury added that policymakers should seriously consider integrating these interventions into standard fertility care, as they may reduce overall healthcare costs while increasing natural conception rates.

FAQs

What does the study say about weight loss and natural conception?

Women with obesity who engaged in structured weight loss programmes were 47% more likely to conceive naturally compared to those who didn’t receive support.

Did weight loss increase the chance of pregnancy overall?

Yes, the odds of any pregnancy (natural or IVF) increased by 21% for women in the intervention group.

What kind of weight loss programmes were included in the study?

The study considered various interventions, including diet plans, exercise regimes, and weight loss medications. Some trials also used low-energy diet replacements.

How much weight did participants lose on average?

Women in the weight loss groups lost an average of 4kg (9lbs) more than those in the control groups.

Is there evidence that weight loss increases live births?

The evidence for increased live births is inconclusive. Some promising signs were observed with low-energy diet programmes, but more high-quality trials are needed to confirm this.

Why is this study important for public health policy?

Because many NHS fertility services deny IVF access to women with a BMI over 30, supporting weight loss could both improve natural conception rates and lower treatment costs.

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