Research
Hormonal
Maintaining a healthy body weight (BMI 20-25) is crucial for fertility, as both obesity (BMI >30) and underweight (BMI <20) are associated with delayed conception, ovulatory dysfunction, and reduced ART success rates.
Aim for a BMI between 20 and 25 if you are trying to conceive. Both being underweight and overweight can disrupt ovulation and reduce your chances of pregnancy. If you are overweight, even a modest weight loss (e.g., 5-10% of body weight) can significantly improve ovulation and fertility.
StrongSupportsVERY_HIGH confidence
Obesity and low body weight can impact on reproductive function by causing hormone imbalances and ovulatory dysfunction... High BMI has also been shown to adversely affect the outcomes of ART treatment... pregnancy rates were halved for very obese women in comparison with women with a normal BMI
Why this rating
Multiple large cohort studies and meta-analyses confirm the effect.
Source
The impact of lifestyle factors on reproductive performance in the general population and those undergoing infertility treatment: a review
Gillian Homan et al. · Human Reproduction Update · 2007
DOI 10.1093/humupd/dml056
narrative_reviewCited 549×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Female age is a primary determinant of reproductive performance, with a significant decline in fertility starting in the mid-to-late 20s and a steep drop after age 35, affecting both natural conception and ART success rates.Strong
- Smoking (active and passive) significantly reduces fertility in both men and women, delaying conception and reducing ART success rates, with mechanisms including DNA damage, altered hormone levels, and zona pellucida thickening.Strong
- Psychological stress is associated with reduced fertility and lower ART success rates, although the evidence is considered equivocal due to measurement difficulties and lack of consensus on defining stress.Moderate
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