How Obesity Affects Fertility

6 min read  |  May 07, 2019  | 

There is a relationship between obesity and infertility. Studies show one consistent underlying factor: fat cells tend to disrupt the balance of hormones that impacts the ability of a woman to get pregnant.

Women who are overweight are prone to Polycystic Ovarian Syndrome (PCOS), a condition characterized by enlarged ovaries, higher levels of male sex hormones, and irregular menstrual cycles. More than 50% of women with this condition are either overweight or obese, and PCOS compounds their ability to conceive.

For a better perspective of the interaction of obesity and PCOS, five colleagues from the University of Miami Miller School of Medicine and I co-authored a study entitled, “Cardiometabolic Health Among Gastric Bypass Surgery Patients with Polycystic Ovarian Syndrome.” Published in the World Journal of Diabetes, it analyzed women with PCOS who underwent Roux-en-Y gastric bypass surgery over an eight-year period. Findings indicated that the risk of cardiometabolic disease varied by ethnicity and obesity could impact glucose tolerance and liver function changes more in Hispanic women with PCOS versus non-Hispanics.

General meta-analysis shows that PCOS decreases significantly after bariatric surgery. In fact, 45.6% pre-operatively to 6.8% at one year, post-operatively. Bariatric surgery not only leads to improved fertility and improvements in PCOS. It can also resolve other illnesses, such as diabetes, hypertension, coronary heart disease, osteoarthritis, and various malignancies, (particularly endometrium), breast cancer, and colon cancer.

If obesity is a factor, multiple pregnancy complications may occur.

One of the most persistent is high blood pressure, and in some severe cases, seizures may even occur. Other challenges faced by women that are obese include an increase in androgen metabolism and elevated levels of estrogen.

Being overweight at a young age is an indicator to perhaps consider bariatric surgery as a preventive measure that will help prevent infertility from developing later in life. To get the best results, and to ensure a safe pregnancy, most bariatric surgeons recommend a one-year waiting period after surgery before couples try to conceive. Many women undergo reproductive therapies to accelerate and augment their ovulation cycles, but if they are obese their chances of pregnancy are limited at best.

About one in eight couples of childbearing age in the United States have trouble conceiving. If both partners are overweight, more problems exist. The National Institute of Health reports that couples with a BMI (body mass index) of over 35 have a 60 percent lower chance of producing offspring than do couples with a BMI of under 25.

Women with a healthy BMI of 20 to 25, generally have about a 15 to 20% chance of getting pregnant in any particular month if they are under the age of 35. Obesity is a cause for irregular periods, poor egg quality, and decreased chances of successful fertility treatments. Men who are overweight will experience lower testosterone levels, fatigue, a loss of libido, and decreased sperm production.

Losing between 5-10% of weight can make a difference in a woman’s ability to conceive. Achieving weight loss requires a healthy lifestyle of quality meals, routine exercise, no smoking, limited alcohol, and a minimum of seven hours of sleep each night.

Common fertility disorders

The female reproductive system is intricate, but no more so than the hard-to-understand words tossed around by the medical community such as gonadotropin secretion, hyperinsulinemia, hyperandrogenemia, SHBG (sex hormone-binding globulin), leptin levels and others. Two more words—adipose tissue and adipokines should be added to the list, and it’s important for women to understand the meaning and function.

Adipose tissue is an endocrine organism that regulates the ability to maintain internal stability (homeostasis) and metabolism. Adipokines secrete “signaling” hormones that regulate a variety of physiological processes. If an abnormality occurs, cells can deteriorate as a result of inflammation. A malfunction may also cause cells to lose their ability to metabolize. A deficiency of white adipose tissue leads to fertility disorders, as does an excess of androgen (male sex hormones such as testosterone).

Obesity is a global issue.

A reported 1.1 billion adults are overweight, and 312 million are classified as obese. Its prevalence has increased in developed countries due to changes in lifestyle, reduced physical activity, changes in nutritional habits, and increased caloric intake. Endocrine disorders, hormonal disorders, psychological disorders, steroids and the use of antidepressants may also lead to obesity. The World Health Organization reports that 60% of women are overweight in the United States and most European countries; 30 percent are classified as obese, and 6% fall into the morbidly obese category.

As medical director of bariatric surgery at UHealth Tower, my colleagues and I are keenly aware of the physical and psychological struggles associated with obesity. As specialists in metabolic weight-loss surgery, our team at the University of Miami Health System has performed more than 6,000 bariatric procedures.

Things to remember 

  • Women who are overweight or obese have less chance of getting pregnant overall. They are also more likely than women of healthy weight to take more than a year to get pregnant.
  • A risk of pre-eclampsia doubles in overweight women and triples in obese women.
  • Overweight women have twice the risk of gestational (pregnancy-related) diabetes and obese women eight times the risk, compared with women of healthy weight.
  • A woman who is obese is more than twice as likely to have a miscarriage as a woman of healthy weight. There is twice the risk that her baby will not survive.
  • Infants born to obese women are more likely to be large for their age, need neonatal intensive care or have a congenital abnormality.

To learn more about your weight loss options, call (305) 243-4400 or visit

In Their Words

Dr. Nestor F. de la Cruz-Muñoz is the chief of the Division of Laparoendoscopic and Bariatric Surgery Department; co-director of the Center of Excellence for Laparoendoscopic and Minimally Invasive Surgery; and professor of surgery in the DeWitt Daughtry Family Department of Surgery at the University of Miami Miller School of Medicine. In addition, he is the medical director for Bariatric Surgery at UHealth Tower, part of the University of Miami Health System. He is the founder and surgical director of Miami’s Surgical Weight Loss Institute, and his practice focuses on general, bariatric, and advanced laparoscopic surgery.

Dr. de la Cruz-Muñoz earned his medical degree from the University of Miami School of Medicine, after graduating with a Bachelor of Science in Biology from Duke University in Durham, North Carolina. He completed his residency in general surgery at Jackson Memorial Hospital in Miami, and became chief resident in 1999.

Renowned nationally and internationally, as a bariatric and general surgeon, Dr. de la Cruz-Muñoz has received numerous awards and has been the keynote speaker at many presentations.

Tags: Dr. Nestor F. de la Cruz-Muñoz, fertility, obesity

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