It’s common for those who are very physically fit to be considered overweight and even obese because muscle weighs more than fat.


I am a specialist in obesity medicine but often receive patient referrals from colleagues who are OB/GYN physicians. Many are surprised to learn that obesity is one of the most prevalent causes of infertility in both sexes. Subfertility or infertility are silent problems that overweight/obese people are increasing forced to face. In fact, infertility now affects one in seven couples actively trying to achieve a pregnancy.

A male’s weight problem can play an equal factor in preventing conception; for starters, obese men may see a decrease in their sperm production due to hormone irregularities. Excess fat around the genitals inhibits testosterone levels and then converts testosterone to estrogen. This layer of fat can also cause the testicles to become heated, further reducing the overall sperm count.

Multiple studies confirmed over the years that men with higher body mass indexes (BMI) had an increased risk of infertility and lower testosterone levels than men who maintained a healthy weight.

How does extra weight affect female fertility?

Research has shown that it is more challenging for obese females to become pregnant, and they may also experience a higher rate of miscarriage compared to healthy-weight women. Obesity ignites abnormal hormone signals, which is believed to be responsible for 10 percent of infertility cases. This hormonal imbalance can cause the overproduction of insulin, which may lead to irregular ovulation.

Fatty cells are responsible for a form of estrogen known as estrone-E. An excessive amount of this causes the body to react similarly to a contraceptive pill. Therefore, it becomes more unlikely that the female will conceive due to the inability of the egg to be released from the ovary.

Another potential issue is polycystic ovary syndrome (PCOS), a medical condition directly tied to excess weight and obesity.

PCOS is a hormonal disorder that can lead to:

  • Decrease or failure in ovulation
  • Irregular menstrual cycles
  • Painful periods
  • Polycystic ovaries
  • Acne
  • Excessive body hair growth

Risks to babies born to obese mothers

From my experience, one of the biggest triggers to get men and women to lose weight before starting a family is the discussion about increased risk factors to babies born to obese mothers, which include:

  • Premature birth.
  • Birth defects can cause problems in overall health, in how the body develops, or in how the body works.
  • Macrosomia (also called large for gestational age or LGA) where newborn infants weigh more than 9 pounds, 15 ounces, which may result in complications during labor and birth; it also increases chances of requiring a C-section.
  • Diabetes, heart disease and obesity later in life.

Severe obesity and the biological clock

As you get older, your fertility decreases. For men and women who are very overweight and over age 35, weight-loss surgery can be an option to quickly lose the extra weight and allow hormones to resume normal function.

As an added benefit, significant weight-loss in obese women prior to pregnancy also helped prevent serious maternal and fetal complications during pregnancy including gestational diabetes and hypertensive disorders, such as pre-eclampsia.

But keep in mind, even after weight-loss surgery, we recommend that you wait at least 12 to 18 months after your bariatric operation to pursue a pregnancy due to the restricted nutrition you are consuming. However, if pregnancy does occur sooner, it can be effectively managed with cautious nutritional care, close monitoring by your bariatric surgeon in partnership with an OB/GYN who has experience treating women who have undergone bariatric surgery.

I’m happy to report that I’ve worked with many individuals and couples battling infertility who lost weight and went on to achieve one or more healthy pregnancies.

When your body is functioning on full throttle, it is more open to accepting the responsibility of creating life and carrying a baby. To achieve this miracle, future mothers and fathers should become as healthy as possible before conceiving in order to bring the healthiest baby possible in the world.