What is BMI?
Body mass index (BMI) is weight divided by height squared (kg/m²). According to the World Health Organization, below 18.5 is underweight, 18.5-24.9 is a healthy weight, 25-29.9 is overweight and 30 or above is obesity.
Weight and fertility
Both low and high body weight can affect hormones and ovulation. In women with polycystic ovary syndrome, losing even 5-10% of body weight can help restore ovulation. Being close to a healthy weight also improves the response to IVF.
Limitations of BMI
BMI does not distinguish muscle from fat and is not accurate in athletes or during pregnancy, when pre-pregnancy BMI is used to guide weight gain.
Frequently Asked Questions
What is the ideal weight for IVF?
Generally a BMI between 18.5 and 30 is the aim. In marked obesity, losing weight before treatment improves both the response and pregnancy safety.