A healthy weight is important for fertility treatment because being overweight or underweight can reduce the chances of success and increase the risk of complications: Obesity Can reduce the success of in vitro fertilization (IVF): Response to medication: Obese women require higher doses of medication to stimulate the ovaries. Egg quality: Obese women produce fewer eggs, and the eggs are lower quality. Implantation: Obese women have a lower chance of implanting an embryo in the womb. Miscarriage: Obese women have a higher chance of miscarriage. Underweight Can make it harder to get pregnant: Estrogen: Being underweight can cause your body to stop making estrogen, which can lead to irregular menstrual cycles and stopped ovulation. BMI A healthy BMI is between 19 and 25. Most fertility doctors will recommend that you try to get close to a healthy BMI before starting treatment. You can try these lifestyle changes to improve your fertility: Eat a healthy, balanced diet Cut back on discretionary foods Eat regular meals and limit unhealthy snacking Drink water instead of sugary drinks and alcohol Make half your plate vegetables at lunch and dinner Use a smaller plate to help reduce your portion sizes Get moving every day Set a realistic weight goal