Fertility and Weight Management

Excess weight can have a negative effect on both women's and men's fertility and is linked to several health complications during pregnancy.
Fertility and Weight Management

In fact, Difficulty carrying a baby to full-term affects more than 7.3 million women of child-bearing age in the United States.1

Obesity and Infertility
Being overweight or obese can lead to imbalances in reproductive hormones. These imbalances can effect menstrual cycles and result in infertility. However, the exact way that obesity impairs ovulation and fertility is not fully understood.

A condition called polycystic ovary syndrome (PCOS) is also linked with obesity and can interfere with the ability to conceive. PCOS is characterized by a group of signs and symptoms (e.g. irregular menstruation, increased testosterone levels, insulin resistance, excess body hair, acne, and weight gain) that can occur in any combination. Medical experts recommend losing weight as the first line of treatment for PCOS; weight loss has been shown to improve both fertility rates and pregnancy outcomes.2,3

Obesity is also connected to having a poorer response and weaker absorption of fertility drugs.4 As a result, higher doses are often needed which may not be as effective.

Obesity can affect men's fertility as well. Two 2010 studies, both with close to 800 men,found that as body mass index (BMI) increased, semen quality decreased.5,6

Obesity and Pregnancy Risks
Research shows that being overweight or obese during pregnancy increases risks for both mom and baby with the risks rising as the degree of overweight increases.7 Complications for mom include increased risk of high blood pressure, gestational diabetes, C-section, and more difficult deliveries.8 Complications for baby include increased risk of higher birth weight, being admitted to the intensive care unit, and around double the risk of having a neural tube defect if the mother has a BMI greater than or equal to 30.9

For these reasons, the American College of Obstetricians and Gynecologists (ACOG) recommend that women should undertake a weight-loss program before trying to become pregnant.10 Even a modest weight loss aimed at moving from obese to overweight may have a positive impact on pregnancy.6

Bottom Line
Excess weight can have a negative effect on a couple's ability to have a healthy baby. However, focusing on making lifestyle changes to lose weight will not only improve health, but may also positively affect future fertility.

This content is reviewed regularly. Last updated June 25, 2012.


1 National Center for Health Statistics: Data from the 2002 National Survey of Family Growth, Fertility, Family Planning, and Reproductive Health of U.S. Women: Data from the 2002 National Survey of Family Growth. (PHS) 2006-1977. 174 pp.

2 Norman RJ, Noakes M, Wu R, Davies MJ, Moran L, Wang JX. Improving reproductive performance in overweight/obese women with effective weight management. Hum Reprod Update. 2004 May-Jun;10(3):267-80. Review.

3 Pasquali R, Gambineri A. Role of changes in dietary habits in polycystic ovary syndrome. Reprod Biomed Online. 2004 Apr;8(4):431-9. Review.

4 van Swieten EC, van der Leeuw-Harmsen L, Badings EA, van der Linden PJ. Obesity and Clomiphene Challenge Test as predictors of outcome of in vitro fertilization and intracytoplasmic sperm injection. Gynecol Obstet Invest. 2005;59(4):220-4. Epub 2005 Mar 7.

5 Martini AC, Tissera A, Estofán D, Molina RI, Mangeaud A, de Cuneo MF, Ruiz RD. Overweight and seminal quality: a study of 794 patients. JFertil Steril. 2010 Oct;94(5):1739-43.

6 Sekhavat L, Moein MR. The effect of male body mass index on sperm parameters. Aging Male. 2010 Sep;13(3):155-8.

7 Raatikainen K, Heiskanen N, Heinonen S. Transition from Overweight to Obesity Worsens Pregnancy Outcome in a BMI-dependent Manner. Obes Res. 2006 Jan;14(1):165-71.

8 Scialli AR. Teratology public affairs committee position paper: Maternal obesity and pregnancy. Birth Defects Res A Clin Mol Teratol. 2006 Feb;76(2):73-7.

9 Watkins ML, Rasmussen SA, Honein MA, Botto LD, Moore CA. Maternal obesity and risk for birth defects. Pediatrics. 2003 May;111(5 Part 2):1152-8.

10 Nutrition During Pregnancy. American College of Obstretricians and Gynecologists. August 2010.