Body mass index (BMI) is one factor that may influence reproductive health in both women and men.

In women, a higher BMI may affect hormone balance, menstrual regularity, ovulation, egg quality, and the body’s response to fertility treatment. It may also increase certain health risks during pregnancy.

In men, a higher BMI may be associated with lower testosterone, reduced sperm count or movement, increased sperm DNA damage, and sexual health concerns. However, these effects vary from person to person.

BMI is only a screening measurement. It does not fully reflect body composition, overall health, age, medical conditions, nutrition, stress, or other factors that influence fertility. Many people with a higher BMI conceive naturally, while people in other BMI ranges may still experience fertility challenges.

When appropriate, gradual and sustainable lifestyle changes may support metabolic and reproductive health. Fertility care should always be individualized rather than based on BMI alone.