Research
Hormonal
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.
Stop smoking immediately if you are trying to conceive. This applies to both partners. Smoking reduces sperm quality in men and egg quality/hormonal balance in women. It also reduces the success of IVF. Quitting improves your chances of natural conception and ART success.
StrongSupportsVERY_HIGH confidence
There is strong evidence of the adverse effects of smoking on fertility operating through a range of pathways in both the general and infertile population... smoking negatively affects sperm production, motility and morphology and is associated with an increased risk of DNA damage... constituents of cigarette smoke may affect the follicular microenvironment and alter hormone levels... increased thickness of the zona pellucida in smokers
Why this rating
Multiple meta-analyses and large cohort studies 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
- 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.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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