Sarah L Berga has devoted her career to one of the most hotly debated subjects in the fertility business: getting pregnant without costly drugs. She is one of a handful of physician-scientists exploring how chronic stress may keep some women from ovulating and how relaxation techniques may help. More precisely, these researchers are examining how chronic stress alters brain signals to the hypothalamus, the walnut-size organ that serves as the master of ceremonies overseeing the delicately timed hormonal dance. Or as Berga puts it, she explores "how the hypothalamus talks to the pituitary that in turns talks to the ovary."

Her research suggests that a cascade of events, beginning with stress, leads to reduced levels of two hormones crucial for ovulation. And her published studies, small but scrupulous, are starting to convince her critics.

In a study of 16 women reported in 2003 in the journal Fertility and Sterility, Berga showed that ovulation was restored in seven of eight women who underwent cognitive behavioural therapy, compared with two of eight who did not get therapy. In 2006, in The Journal of Clinical Endocrinology & Metabolism, she reported that women who did not ovulate had excessive levels of cortisol, a stress hormone, in the brain fluid.

Berga spoke recently about her research from her office at Emory University in Atlanta. You've studied not only people but also animals. What did those studies tell you about stress? Before we did the 16-woman study, we studied monkeys. We found that when we stressed monkeys alone, 10 percent stopped menstruating temporarily. When we added exercise and limited their food intake, again about 10 percent stopped enstruating temporarily. But when we combined stress, exercise, and cut down on food, 75 percent became amenorrheic.
Then you did a similar study in which two groups of women — one group with normal ovulation, the other group with stress-related amenorrhea — exercised almost to their full potential. What did you find?

We saw that if you are stressed when you start exercise, your body reacts differently than if you are not chronically stressed and exercise. Not only does it appear that exercise was more stressful for already stressed women, but certainly exercise did not help them lower their stress hormones, which is of course one reason people take up exercising.

Are you saying that a woman who may have had a stressful month at work is hurting her fertility? Isn't life without stress impossible? We are talking about chronic stress related to behaviour or personality. People are designed to endure acute stress. That is a part of life. I am telling women, and men, that it is important to find a balance and learn to cope with their stress.