Why does obesity affect fertility

The ideal weight for conception depends on how tall you are. Your body mass index BMI is a number based on your height and weight. The healthy BMI range is between It can also lead to difficulties with assisted reproduction , such as in-vitro fertilisation IVF , ovulation induction and intracytoplasmic sperm injection ICSI.

Obesity is also associated with polycystic ovary syndrome PCOS , a common cause of low fertility or infertility. This is likely due to a combination of factors including:. Weight loss in men who are overweight or obese can significantly increase total sperm count and quality.

Reaching a healthier weight at least 3 months before conception can improve the chance of conception. This is because sperm take about 3 months to develop and being in the healthy weight range during this time helps develop healthy sperm.

Getting closer to a healthy weight before conception increases the chance of the baby being healthy at birth and into adulthood. Obesity and excess weight gain during pregnancy is also linked with a number of pregnancy complications.

These include increased risk of:. Babies born to very overweight mothers have an increased risk of childhood and adult obesity and other long-term health problems. While the facts about obesity and reproductive outcomes can seem daunting, there is some good news. In women who are obese, even a small weight loss improves fertility and pregnancy health.

Also, some diet and lifestyle changes that limit excessive weight gain during pregnancy can improve health outcomes for both mother and baby. If you are planning to get pregnant, starting a healthy eating and exercise plan now improves your chances of getting pregnant and having a healthy baby. Studies have found that obesity reduces the rate of pregnancy and live births in women using ART, and increases the rate of miscarriage. But weight loss through diet, lifestyle and other changes significantly improves these outcomes.

Ask your doctor about any dietary supplements you may need, such as folic acid and iodine. Enter your height and weight into the tool to see your BMI.

A BMI between 19 and 24 is considered normal; less than 19 is considered underweight. A BMI between 25 and 29 is considered overweight and greater than 30 places you in the category of obese. Many underweight, overweight, and obese women have no problem getting pregnant.

But others will have problems conceiving, most often due to ovulation problems failure to release eggs from the ovaries. A BMI of Being underweight can cause your body to stop making estrogen.

This can cause irregular menstrual cycles. You may stop ovulating and getting your period. This is especially true if you are losing weight because you are not eating enough or because you are exercising too much, which may be signs of an eating disorder like anorexia nervosa.

Then your body needs to be able to support a developing baby in the womb. Every woman is different, but studies show that for women who have overweight or obesity, losing weight raised their chances of getting pregnant. Losing weight also helped menstrual cycles return to normal. Women who need to gain weight before getting pregnant should gain weight gradually and talk to their doctor or nurse about how to gain weight safely.

How much weight you should gain during pregnancy depends on your body mass index BMI before getting pregnant. Having overweight or obesity during pregnancy raises your risk for problems during pregnancy. Also, even if you do not have overweight or obesity, gaining more weight than recommended can cause the same problems. Talk to your doctor, nurse, or midwife about healthy weight gain during pregnancy to help lower your risk for these health problems.

Learn more about pregnancy complications. Babies born to mothers with overweight or obesity are at higher risk for health problems, including: 3. Babies born to mothers who are underweight women with BMIs lower than For more information about weight, fertility, and pregnancy, call the OWH Helpline at or check out the following resources from other organizations:.

Central obesity, which is around the abdomen, is generally considered the higher risk for cardiovascular disease, diabetes and ovulation difficulties. Women who carry weight more proportionally or in their lower extremities or butt tend to have a little less risk.

Those women may be genetically wired to have that body type, while central obesity is usually the result of lifestyle and habits. There are all sorts of factors involved. So while there is no magic number, 10 pounds is a good place to start.

To help you reach your goal, focus on making healthy choices every day. That can sometimes be the difference in helping your body ovulate regularly. Achieving a healthy body weight has a much better payoff, especially with all the risk factors that come with being overweight and pregnant. A healthy weight can lead to a smoother pregnancy. Sleep apnea is also more common among women who are obese.