Feb. 24, 2011 -- Stress and infertility have long been linked, with stress sometimes blamed when a woman can't get pregnant naturally or with fertility treatments.
Now, a new report finds that a woman's stress levels don't adversely affect her chances of getting pregnant in a single fertility treatment cycle.
''A lot of people worry that their stress, anxiety, tension, and worry might reduce their chances of pregnancy with a specific treatment cycle, but there is no evidence of that," says researcher Jacky Boivin, PhD, a health psychologist at Cardiff University in Wales. Boivin's team evaluated the results of 14 previously published studies.
The researchers aren't saying stress never has an effect on fertility treatment, Boivin tells WebMD. "It could be stress has an impact on treatment, in that you give up sooner," she says. And stress can reduce quality of life during the fertility treatments, so she does urge women undergoing fertility treatments to reduce excess stress.
"All [the research] is saying is, whatever stress you are experiencing is not going to impact whether you get pregnant on that particular cycle," Boivin tells WebMD.
But U.S.-based experts, including Alice D. Domar, PhD, director of the Domar Center for Mind/Body Health in Boston, who has researched infertility, says the jury's still out on the stress and infertility link.
"I think it's way too early to say stress has no impact on outcome, or to say stress does have an impact," she says. The new report, she says, ''counters the majority of the research."
Boivin looked at 14 studies including 3,583 infertile women undergoing a cycle of fertility treatment in 10 countries. Only two of the 14 studies were U.S.-based.
The women's average age ranged from nearly 30 to nearly 37 years old. They were infertile for a range of 2.6 to 7.8 years.
Infertility affects up to 15% of the population of child-bearing age, Boivin says.
The women's stress levels were measured before treatment started, using standard measures. The time of assessment varied from study to study -- sometimes a few days before treatment and sometimes a few months.
The researchers found no effect of the stress on pregnancy outcome for the cycle studied.
''Forever and ever we hear these stories," Boivin tells WebMD. People will say they knew a friend trying to get pregnant who adopted, and then got pregnant. Or a couple trying to conceive goes on a holiday and she comes back pregnant.
''Evolutionary models suggest that stress suppresses fertility in nonhuman mammals," she says, but adds that there is no evidence it happens in the context of fertility treatments in women.
What she speculates might happen in stressed-out women undergoing fertility treatments is that the mechanism of suppression somehow turns itself off.