How Much Does Lifestyle Actually Matter?
Lifestyle factors influence fertility in both partners, though the size of the effect varies. Smoking, severe under- or overweight, heavy alcohol use and untreated medical conditions have well-documented major effects. Diet and moderate alcohol have smaller but real effects. Stress and sleep matter, though it is hard to separate cause from effect. Importantly, lifestyle changes take 3-6 months to influence egg quality and around 3 months to influence sperm quality (the time it takes to make new sperm). So changes made now affect outcomes in a few months, not next cycle.
High-Impact Changes
Stop smoking: Smoking reduces fertility, accelerates ovarian ageing, harms sperm DNA and increases miscarriage. Quitting is the single most impactful change for many couples.
Achieve a healthy weight: Both BMI under 19 and over 30 reduce fertility. Even a 5-10% weight change can restore ovulation in PCOS.
Limit alcohol: Heavy drinking (more than 14 units per week) clearly affects fertility in both sexes. Conservative advice is to avoid alcohol when actively trying to conceive.
Address chronic conditions: Untreated thyroid disease, diabetes, depression and pelvic infections all affect fertility. Optimise before trying to conceive.
Moderate caffeine: Limit to 200mg per day (around 2 cups of coffee). Higher intake is linked to longer time to conceive and increased miscarriage.
Moderate-Impact Changes
Mediterranean-style diet: Rich in vegetables, whole grains, fish, olive oil and pulses. Linked to better fertility outcomes and improved IVF success
Regular moderate exercise: 30-45 minutes most days improves fertility. Excessive exercise can suppress ovulation in lean women
Quality sleep: 7-9 hours per night supports hormonal balance. Shift work is associated with reduced fertility
Stress management: Severe stress affects ovulation and may reduce IVF success. Mindfulness, therapy and yoga have all shown benefit
Avoid environmental toxins: Reduce exposure to BPA, phthalates and certain pesticides where practical
Folic acid supplementation: 400mcg daily for at least 3 months before conception (higher dose if specific risk factors)
Things That Are Often Overrated
Detox cleanses and "fertility cleanses": No evidence of benefit and may be harmful
Expensive supplement stacks: Most women only need folic acid, vitamin D and possibly omega-3
Herbal remedies: Limited evidence and many are unsafe in pregnancy. Always discuss with a doctor
Strict elimination diets: Unless you have a diagnosed intolerance, restrictive eating creates stress without fertility benefit
Sex positions: No evidence that any position improves chances of conception
Lying flat after sex: No evidence this helps. Sperm reach the uterus within minutes
When to Get Professional Help
You have made significant lifestyle changes for 6 months without conception
You have a BMI under 19 or over 30 and need help reaching a healthy weight
You smoke and want help quitting (NHS stop-smoking services are highly effective)
You think you may have an undiagnosed condition affecting fertility
You are struggling with mental health while trying to conceive