Obesity Report: Why Some People Need to Lose Weight to Get Pregnant

The American Society for Reproductive Medicine Practice Committee recently published a report titled "Obesity and Reproduction” in its journal Fertility and Sterility. The report offers insights on why some people need to lose weight to get pregnant, and in this blog, I'll share some of those insights.

Obesity Affects Many

There is a worldwide epidemic of obesity. In the United States alone, almost two thirds of women and three fourths of men are overweight or obese, as are nearly 50% of women of reproductive age and 17% of their children ages 2–19 years. In comparison, in Denmark, a third of women and one-half of men ages 25-44 are overweight or obese.

Obesity is defined based on having a certain body mass index. It is now well documented that obesity increases the risks of high blood pressure, cholesterol problems, diabetes and increased risk of a heart attack. Other problems include sleep apnea, breathing problems, joint problems and increased risk of developing cancer. In the U.S. alone, obesity results in medical bills exceeding $200 billion per year!

So what does the report say about obesity and reproduction? First of all, many obese women and men are fertile. But there are links between obesity and infertility.

Fertility Problems Associated With Obesity

Obese women have a higher incidence of irregular menses and lower chance of conception. The excess fat is hormonally active and induces hormonal imbalances that impact ovarian function. These hormonal imbalances result in ovulatory disturbances (reduced LH pulse frequency and diminished progesterone levels in the second half of the cycle).

Obesity is commonly associated with ovulatory problems with resultant infertility. The good news is that ovulatory function improves and pregnancy rates frequently improve with weight loss.

The response to fertility drugs is less than optimal in many obese women. They often require a higher dose of medications, produce fewer mature follicles, have increased egg abnormalities and there is a decreased chance of ovulation.

The pregnancy rates with in vitro fertilization (IVF) are lower in obese patients. At InVia Fertility Specialists, we require that obese patients lose weight (reaching a BMI of less than 35 kg/m2) before they will be accepted in our IVF program, and we offer them support in implementing the Ideal Protein diet to help them do so.

The uterine lining is less receptive in obese women. A recent study showed a 25% lower pregnancy rate in gestational carriers with a BMI greater than 35 kg/m2 when compared with those with a BMI less than 35 kg/m2. Obese donor egg recipients will have a lower pregnancy rate.

Obese women also have a higher rate of miscarriage (at least 30% increase) compared to normal-weight women.

Pregnancies are more complicated in obese women.

There is an increased risk of diabetes and high blood pressure during pregnancy. Preterm delivery, stillbirth, obstructed labor, fetal distress, increase chance of C-Section, early neonatal death, and small- or large-for-dates babies are all increased.

The report also states that obesity in men may be associated with impaired reproductive function.

Successful Ways to Lose Weight to Get Pregnant

Lifestyle modification

In women and men is the first-line treatment for obesity, followed by adjunctive medical therapy.

Bariatric surgery

In women and men is an important adjuvant to lifestyle modification and medical therapy for weight loss, but pregnancy in women should be deferred for 1 year after having this operation.

Preconceptional counseling

Obese couples should address the reproductive and maternal-fetal consequences of obesity.

The health benefits of postponing pregnancy to achieve weight loss must be balanced against the risk of declining fertility with advancing age of the couple.

At InVia Fertility Specialists, we have had great success with our patients who participate in the Ideal Protein Diet program. Many of them are losing weight and keeping it off without feeling hungry or tired, and many are getting pregnant naturally as they lose weight.

To see a fertility specialist who will help you lose weight to get pregnant, make an appointment at one of InVia's four Chicago area fertility clinics.