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."
The study is published online in BMJ.
Measuring Stress Levels
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.
''Your body prefers to reproduce when all conditions are optimal," she says. But when those conditions don't become reality, the stressed-out woman may decide she is going ahead regardless, Boivin says.
She's not suggesting infertile women ignore the stress of the treatment or everyday life. ''What the stress really does is decrease your quality of life," she says. "People should pay attention to stress and reduce that to improve their quality of life during the treatments."
She gives patients suggestions on how to do so, including a list of tips meant to be helpful, for instance, when women are awaiting news about whether they have become pregnant with fertility treatment. Among the suggestions are to think more about the positive aspects of a difficult situation.
Boivin reports receiving speaker fees from pharmaceutical companies EMD Serono Inc. and Merck & Co., and a research grant from Merck Serono S.A.
Stress Reduction Helpful?
Women who volunteer to be in the studies of stress and infertility are often among the less-stressed women, agreeable to putting in the time required for the study, says Domar, who reviewed the abstract of the study for WebMD.
The body of medical literature does suggest a stress and infertility link, she tells WebMD. "There have been close to 30 studies in the last 15 years looking at the impact of stress on IVF outcome, and most of them did show a positive relationship. The more stress there was, the less likely the woman was to get pregnant."
Together with Boivin, Domar will conduct a study soon to see if stress reduction can reduce dropout rates of those undergoing infertility studies. Merck & Co. will fund the research.
A fertility expert in practice, Richard J. Paulson, MD, also sees value to reducing stress in women undergoing fertility treatment. "There are all kinds of studies that suggest ancillary stress-reducing treatments seem to make a difference in the outcome of ART [assisted reproductive technologies]," he tells WebMD, including research on acupuncture, for instance.
''We think the mind-body approach seems to help," says Paulson, chief of the division of reproductive endocrinology and infertility at the University of Southern California's Keck School of Medicine, Los Angeles. He directs the fertility program there.
While the study results may be reassuring to women, he says, ''it does not rule out the benefit of the kind of mind-body interventions that have been studied in other reports and shown to be beneficial."