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Lose Weight, Increase Fertility
November 2, 2012
One third of Americans are overweight, and another one-third are obese, according to the Centers for Disease Control and Prevention (CDC). Losing weight not only lowers blood pressure and improves blood sugar levels but weight loss is associated with increased fertility potential in women and men.
Typically both partners in a couple have similar diet and exercise habits, and a similar Body Mass Index (BMI). If both partners are overweight, chances are their fertility issues will be compounded, says Kathryn Calhoun, M.D., a fertility doctor with Atlanta Center for Reproductive Medicine. “We know from research in women who have used IVF and women who haven’t used IVF that it affects all parts of the reproductive cycle,” Calhoun says. “And we know that being overweight can affect a man in terms of sperm production, erectile function, and in terms of libido.”
Women, Weight and Fertility
In overweight women the hypothalamus, pituitary and ovaries are all disrupted. But the most common way that body weight affects reproduction is that it alters ovulation. It also affects rates of conception, rates of miscarriage, birth defects, birth weight, pre-eclampsia, gestational diabetes and even mode of delivery - women who are over their ideal body weight are more likely to have a c-section.
“At the very most, Calhoun says, “It affects your longevity and your lifespan and how healthy you’re going to be as a parent. You want to be alive to see this baby that we’re creating get married and graduate college. You don’t see a lot of 70 and 80 year olds who are morbidly obese,” she adds.
Men, Weight and Fertility
The scrotum contains the testicles and the testicles produce sperm. You’ve probably heard that heat near the scrotum can impact sperm production. But what you may not know is that fat surrounding the testicles can elevate the temperature. Thus excess fat can hinder sperm production. In addition, men who are overweight or obese are more apt to have diabetes and vascular trouble which can impact the ability to have an erection.
At a more central level, Calhoun explains, fat is constantly converting male hormones or testosterone to estrogen. So if you have more fat, you have more estrogen. Higher estrogen and lower testosterone can not only impact well-being, but can impact sperm production. Obstructive sleep apnea, untreated, also causes a central suppression of testosterone, Calhoun says.
What’s an Overweight TTC Couple To Do?
As anyone who’s tried to modify their dietary and exercise habits knows, it’s a daily battle. Dr. Calhoun laughs as she repeats what a colleague says, “You only have to exercise on the days that you eat.”
In men, testosterone or sperm production can recover with weight loss, or use of a CPAP machine for those with sleep apnea. It takes approximately 70 days to produce sperm, so typically following weight loss, it may be one to three months before there’s a change in sperm production.
Typically the older you get, the less likely you are to have an isolated fertility problem, such as anovulation – or lack of a period. But the older we get the more likely we are to have age effects on the ovaries, some tubal problems, or uterine problems. “In isolation, with even modest weight loss, women can see a return to ovulatory cycles. But if not, they’ll be better able to respond to ovulation induction medicines,” Calhoun says. The heavier you are or the more elevated your BMI is, the more medicine you require – and despite the higher doses these women still experience a lower response to the fertility drugs and a lower pregnancy rate.
In women, weight loss as low as 5 to 10 percent of body weight can restart ovulation. The optimal BMI range for successful pregnancies and live births is 20 to 28.