Previous research has suggested that stress may decrease the likelihood of conception, but few studies have investigated this association among couples in the general population.
Now, a new study, published in the American Journal of Epidemiology, reveals that higher levels of stress are linked to lower odds of conception for women, but not for men.
“Although this study does not definitely prove that stress causes infertility, it does provide evidence supporting the integration of mental health care in preconception guidance and care,” says lead author Amelia Wesselink, a doctoral student at Boston University School of Public Health (BUSPH).
The researchers tracked 4,769 women and 1,272 men with no history of infertility and who had not been trying to conceive for more than six menstrual cycles. They used data from the Pregnancy Study Online (PRESTO), an ongoing preconception cohort of North American pregnancy planners that follows couples for 12 months or until pregnancy, whichever comes first.
The researchers measured the perceived stress of the subjects using the 10-item version of the perceived stress scale (PSS), which is designed to evaluate how unpredictable, uncontrollable, and overwhelming an individual finds their life circumstances.
The items referred to the past month, with five response choices ranging from 0 (never) to 4 (very often), up to a total of 40, with a higher total score indicating a higher level of perceived stress.
Each partner completed the PSS at baseline, and women also completed the PSS at each bi-monthly PRESTO follow-up. The baseline questionnaires also included a range of demographic and behavioral factors, including race/ethnicity, household income, diet, sleep, and frequency of intercourse.
On average, baseline PSS scores were about 1 point higher among women than men, and the average follow-up PSS scores among women remained fairly constant over the 12 months that they participated in the study.
The findings show that women with PSS scores of at least 25 were 13 percent less likely to conceive than women with PSS scores under 10. This link was stronger among women who had been trying to conceive for no more than two menstrual cycles before joining PRESTO than among women who had been trying for three or more cycles before enrolling. The association was also stronger among women under 35 years old.
The researchers hypothesize that, if the association between higher levels of stress and lower odds of conception is a cause-and-effect association, a small proportion of that link could be due to decreased intercourse frequency and increased menstrual cycle irregularity.
The findings did not show a link between men’s PSS score and the chances of conceiving. However, couples in the study were about 25 percent less likely to conceive when the man’s PSS score was under 10 and the woman’s was 20 or higher.
The authors wrote that this is the first study to suggest that “partner stress discordance” may impact the odds of conception, although the finding was imprecise and speculative.