Stress and Fertility

Stressed out? You'll probably have some trouble getting pregnant. That's the conclusion of scientists studying human fertility at the University of Louisville School of Public Health and Information Sciences.

"If you are feeling more stress than you usually do [around ovulation time], you are 40 percent less likely to get pregnant that month," said study author Kira Taylor, assistant professor of epidemiology and population health at the university.

Taylor's study evaluated 400 women, 40 years old and younger. All the women were sexually active and not using contraception. It's the first study to examine stress at different time periods in a woman's monthly cycle, to determine if there are different effects at different points.

The women graded their stress levels on a scale of 1 to 4 each day, for 20 cycles, or until pregnancy occurred. The average at the end of the study was 20 cycles.

"Only about a third were actively trying to get pregnant, but all were having unprotected sex, without birth control," Taylor noted.

Over the course of the study, 139 of the women became pregnant.

The presence and degree of stress in the lives of the ovulating women had a dramatic effect on their chances of pregnancy. A mere one unit rise in a subject's “stress number” during the ovulation windowproduced a 46 percent reduction in conception. The researchers factored day 14 of the cycle as the time of ovulation.

The researchers looked at other times in the cycle as well, but "we did not find an effect of stress on implantation," Taylor said. "Implantation generally occurs six to 10 days after ovulation, if you have conceived."

The numbers held up even when the investigators took into account other factors, such as age, body mass index, alcohol use and how often sex occurred.

The researchers did not look at the reasons why stress affected conception, but Taylor speculated that "stress disrupts the signaling between the brain and the ovaries, and reduces the chances of ovulation."

Knowing all this, what can women – living in these most stressful of times – do to ensure they conceive?

Taylor suggests that moderate exercise, five times a week for 30 minutes, can reduce stress. But she also warns against exercising to extremes, as that of itself can reduce the likelihood of conceiving.

The study was published online in the Annals of Epidemiology.