BMI is a screening tool, not a judgement

Body mass index compares weight with height. It is an imperfect measure and does not directly measure body fat, fitness or overall health. Clinics still use it because it can help identify situations where treatment or sedation may need additional planning. At Oocyt we recommend a BMI of 20-28kg/m2 for safe donation.

Why clinics set limits

Ovarian stimulation medication, ultrasound monitoring, sedation and egg retrieval can be more complex at very low or high body weights. Some clinics therefore use BMI ranges within their donor eligibility criteria.

The exact limit is not universal

There is no single BMI cut-off used by every fertility clinic. A programme may set a stricter donor range than it uses for patients undergoing IVF with their own eggs because donor treatment is elective and clinics aim to keep risk particularly low.

What BMI cannot tell you

BMI does not account well for muscle mass, body composition, ethnicity or metabolic health. It should not replace an individual medical assessment.

If you are outside a clinic’s range

Ask whether the limit is set by the clinic, anaesthetic team or donor programme, and whether it is absolute. Avoid rapid weight loss or unsafe dieting simply to meet a number. Your health matters more than qualifying for a donation cycle.

Oocyt perspective

Eligibility criteria should be explained respectfully. A clinic should be able to tell you how its BMI policy relates to safety and why a particular range is used.