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How Being Severely Underweight or Overweight Affects Fertility

If you’re thinking about getting pregnant, it’s a good idea to achieve a healthy weight first. Being severely overweight or underweight affects your ability to conceive and can cause complications during your pregnancy.

While women of all sizes can get pregnant, achieving a healthy weight increases your chances of conceiving and of having a healthy pregnancy and thriving baby.

At California Center for Reproductive Health, our fertility specialists, Drs. Eliran Mor and Irene Woo, often recommend you take steps to reach a healthy weight if you’re struggling with infertility. Here’s why.

Being underweight can affect your cycle

When you have a body mass index (BMI) of 18.5 or less, it’s an indication that you’re underweight. A BMI of 17.5 or less may be a sign of an eating disorder, which should definitely be addressed prior to conception.

When your body senses that you’re too thin, it may stop making the female hormone estrogen. Your periods become irregular or disappear altogether, a sign that you’re not ovulating (releasing an egg every month). Your body senses that you may not be healthy enough to support a developing baby in the womb.

If you don’t ovulate, there’s no egg to be fertilized and pregnancy can’t occur.

Being overweight also affects ovulation

Being overweight or obese may also interfere with ovulation. Fat cells produce estrogen, the same hormone produced by your ovaries. When you have too much natural estrogen, your body reacts in the same way as it does when you take larger doses of the hormone in birth control, like the pill or Depo-Provera® injections. Too much estrogen suppresses ovulation.

Overproduction of natural estrogen from fat cells can also fool your body into thinking you’re already pregnant. As a result, you don’t ovulate and you have irregular or absent periods.

Extra weight can also interfere with fertility treatments, including in vitro fertilization. If you want to maximize your chances of getting pregnant with assisted reproductive technology (ART), we may recommend you work toward a healthy weight first.

What if I have polycystic ovary syndrome?

About 10% of women have polycystic ovary syndrome (PCOS). This hormonal and metabolic condition can cause you to gain weight or have trouble losing excess weight. PCOS can affect your fertility by suppressing ovulation.

If you have PCOS, we can work with you to help you achieve a healthier weight and provide treatments that can help you get pregnant. You may benefit from fertility medications and in vitro fertilization.

Can weight affect male fertility?

Men who are obese may experience changes in their testosterone levels that affect their ability to produce viable sperm. Low sperm counts and sperm with low motility occur more often in men who are overweight or obese than in men who are at healthy weights.

What should I do?

Before assuming it’s your weight that’s causing your infertility, make an appointment at our office to have all relevant fertility factors considered. Your age, genetic history, and gynecological health, as well as your partner’s health, all play a role in your ability to get pregnant.

We can help support you in losing or gaining weight in a healthy way if we feel that can help your fertility journey. Achieving a healthy weight with a nutritious diet, exercise, and stress reduction is always a good way to promote better health, too.

Our fertility specialists at California Center for Reproductive Health understand how frustrating and devastating infertility can be. We do everything possible to support your efforts to overcome infertility and experience a healthy pregnancy. Call today for an appointment or use the online tool to schedule.