Weight and fertility

Revised 2015


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How do I know if I am a good weight for pregnancy?

One of the easiest ways to determine if you are underweight or overweight is to calculate your body mass index (BMI). There are many tables available online (search term: BMI table). Enter your height and weight into the tool to see your BMI.

What is a normal 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.

How does weight affect fertility in women?

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 18.5 or less (underweight) often causes irregular menstrual cycles and may cause ovulation to stop altogether. A BMI of 17.5 or less could indicate an eating disorder. Women at less than normal BMI should work with their doctor to understand the cause of this situation, and develop strategies to correct it.

A BMI in the obese range may also lead to irregular menstrual cycles and ovulation. However, even obese women with normal ovulation cycles have lower pregnancy rates than normal weight women, so ovulation isn’t the only issue. A visit to a healthcare professional before becoming pregnant can help identify other disorders related to obesity that impact pregnancy such as thyroid disease, insulin resistance, and diabetes.

Does obesity affect the chance of getting pregnant with treatment and having a healthy baby?

There is good evidence that obesity lowers the success rates of in vitro fertilization (IVF). Studies have shown lower pregnancy rates and higher miscarriage rates in obese women. Obese women are at an increased risk for developing pregnancy-induced (gestational) diabetes and high blood pressure (pre-eclampsia). Obese women also have a higher chance of delivering by cesarean section. Children of obese mothers are at increased risk of some birth defects and having a high birth weight.

Are there fertility problems in men with obesity?

Obesity in men may be associated with changes in testosterone levels and other hormones important for reproduction. Low sperm counts and low sperm motility (movement) have been found more often in overweight and obese men than in normal-weight men.

Should I try to lower my BMI if I am in the obese category before I try to get pregnant?

You should first consult with a healthcare provider. He or she will consider all factors, including your age and any other infertility factors, before making a recommendation about whether you should try to lose weight first. Changing your diet and lifestyle (for example, exercise) combined with a program that may provide group support is an effective step, but not always the appropriate first step if your age or your BMI is above 40. Weight loss surgery (bariatric surgery) is the most effective treatment for weight loss in women with a BMI greater than 40.

I have polycystic ovary syndrome (PCOS) and am overweight, will I need to do anything different?

PCOS is a very common condition in young women (about 8%–10%). Not all women with PCOS are overweight or obese, but many women with PCOS have signs of insulin resistance and/or obesity. A low-calorie diet and exercise  may lead to weight loss, regular menstrual cycles, and ovulation.

However, women with PCOS may require additional treatment to get  pregnant, including medications to decrease insulin resistance. These women  should seek the assistance of a reproductive endocrinology and  infertility  specialist. For more information about PCOS, please see the ASRM  fact  sheet titled Polycystic ovary syndrome. To find an infertility  specialist near  you, use the ASRM Find a Healthcare Provider tool on  ReproductiveFacts.org.

Weight

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Female Fertility

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SART Fertility Experts - Preconception Counseling

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Female Fertility Journey

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SART Fertility Experts - Endometriosis

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SART Fertility Experts - IVF: Cycles of Hope and Heartbreak

Does stress cause infertility or is it the other way round?  Listen to the Episode

Male Fertility/Andrology

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SART Fertility Experts - Wellness and Fertility: Diet, Sleep and Exercise

Drs. Timothy Hickman and Rashmi Kudesia discuss the links between lifestyle and fertility. Listen to the Episode
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Male Fertility Journey

About 20% of infertility cases are due to a male factor alone. Another 30% involves both male and female factors.

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SART Fertility Experts - Urology and Male Reproductive Health

Male infertility is less often discussed than female infertility. Dr. Ajay Nangia discusses when a man should seek help with conceiving.
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SART Fertility Experts - Male Factor

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SART Fertility Experts - Male Fertility

Did you know that up to 40% of infertile couples suffer from male factor infertility? Listen to the Episode

Polycystic Ovary Syndrome (PCOS)

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SART Fertility Experts - PCOS

As the most common hormonal disorder in women, PCOS is a disruptive problem that impacts aspects of a woman’s health, including getting pregnant. 
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Hirsutism and Polycystic Ovary Syndrome (PCOS) (booklet)

Polycystic ovary syndrome (PCOS) is a condition in which the ovaries contain many cystic follicles associated with chronic anovulation (lack of ovulation) and overproduction of androgens (male hormones). View the booklet
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Ovarian drilling for infertility

Often, women with polycystic ovary syndrome (PCOS) do not have regular menstrual periods. View the fact sheet
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Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome is a common hormone disorder that affects 5-10% of women. View the fact sheet
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Conditions Treated with Adnexal Surgery

Surgery can be used to treat problems with your ovaries or fallopian tubes such as cysts, endometriosis or infections. Adnexal surgery involves any of the organs that are on the sides of (“next to”) the uterus (womb), such as the fallopian tubes and ovaries.

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Insulin-sensitizing agents and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common reproductive disorder, affecting 5% to10% of women of reproductive age. View the Fact Sheet

Fact Sheets/Booklets

View more fact sheets and booklets written by the ASRM Patient Education Committee.
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Assisted Reproductive Technologies (booklet)

This booklet will help you understand in vitro fertilization (IVF) and other assisted reproductive technology (ART) that have become accepted medical treatments for infertility.
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Hormonal Contraception

Hormonal contraceptives contain a progestin (progesterone medicine) with or without an estrogen.
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What do I need to know about Zika virus and trying to have a baby?

Common symptoms include fever, rash, joint pain, conjunctivitis (red eyes), muscle pain, and headache.
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Third-Party Reproduction

The phrase “third-party reproduction” refers to involving someone other than the individual or couple that plans to raise the child (intended parent[s]) in the process of reproduction.

Resources For You

The American Society for Reproductive Medicine (ASRM) is committed to providing patients with the highest quality information about reproductive care.

Find a Health Professional

Connect with reproductive medicine experts who will guide you through your unique journey. Our search tool allows personalized matches based on location, specialization, and expertise. Take control of your reproductive health with compassionate providers, innovative treatments, and unwavering support.
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