I am 24 years old and very concerned I will never be able to conceive. I began compulsively dieting at 22, and by the end I was quite unhealthy and underweight. During this time I did not have a period for over a year. Now that my weight is normal again, I have periods, but they're erratic compared to when I was a teenager. I have been having unprotected sex in a monogamous relationship for well over a year without getting pregnant. I literally just feel "immune." Could I have permanently damaged my reproductive capability through obsessive dieting?

nbsp;--nbsp; Erin

Eating disorders such as anorexia or bulimia may have a long-lasting effect on the hypothalamus, an area of the brain that regulates your menstrual cycles with regular pulses of hormones. Still, there are many factors that can interfere with your cycles. Stress, excessive exercise, diet, narcotics and weight loss can all contribute to decreased hormonal pulse activity. While reducing stress, eating right and maintaining a normal body weight can restore normal menstrual cycles in many women, others need medical therapy to achieve this.

While you may have been glad not to have periods when you were not trying to get pregnant, the absence of your periods can cause problems. When the hypothalamus takes it easy and your periods stop, your estrogen level is usually low. Over time this can result in osteoporosis, a bone-thinning disease that can lead to fractures. So, even when you are not trying to conceive, medication such as birth control pills or other forms of estrogen replacement are advisable.

What about when you want to conceive? Clomiphene (Clomid, Serophene) is often used to help women with irregular periods. But in women with an underactive hypothalamus, clomiphene rarely works. We can predict whether it might be of benefit. We first check to make sure you are not pregnant. Then we can give the medication progesterone (Provera) in an attempt to bring on your menses. If you have a period, you are making estrogen, and that suggests clomiphene may work. If you do not have a menstrual period, then you may need injections of hormones FSH (Fertinex, Follistim, Gonal-F) to stimulate your ovaries to make eggs.

A newer method, now undergoing trials, involves the drug Naltrexone, an opioid blocker. Opioids are the body's natural painkillers (similar to morphine). In times of stress or malnutrition, your body says NO to pregnancy and secretes more opioids, which can turn off the hypothalamus. This makes a lot of sense -- you would not want to be pregnant in times of famine or severe stress. Some women, it seems, just make too much of their own opioids. "Runner's high" is also a case of high opioid levels. If we use Naltrexone, we can block the opioids; that may help some women re-establish normal menses. While the medication is inexpensive and usually well tolerated, it is not approved for this use and is considered experimental by most insurance companies. That leaves the injectable medications the only option for many women.