Experiencing high levels of stress can reduce fertility and lower odds of conception for women, a study has found.
The researchers 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.
For the new study, the researchers followed 4,769 women and 1,272 men who did not have a history of infertility and had not been trying to conceive for more than six menstrual cycles. “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,” said Amelia Wesselink, a doctoral student at Boston University in the US.
The researchers measured perceived stress using the 10-item version of the perceived stress scale (PSS), which is designed to assess 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. Both partners 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 one 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 researchers found women with PSS scores of at least 25 were 13 percent less likely to conceive than women with PSS scores under 10. This association 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 found that, if the link between higher levels of stress and lower odds of conception is a causal association, a small proportion of that association could be due to decreased intercourse frequency and increased menstrual cycle irregularity. They did not find an association between men’s PSS score and the likelihood of conceiving.