New U.S. research has found that higher stress levels may lower a woman's chance of conception, although the same association was not found for men.
Led by researchers at Boston University School of Public Health (BUSPH) and published in the American Journal of Epidemiology, the new study gathered data from the Pregnancy Study Online (PRESTO), an ongoing study that follows American and Canadian couples for 12 months or until pregnancy, whichever comes first.
The researchers looked at 4,769 women aged 21 to 45 years and 1,272 men age 21 and over who did not have a history of infertility and had not been trying to conceive for more than six menstrual cycles.
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Participants' perceived stress was measured using a 10-item Perceived Stress Scale (PSS), which was designed to assess how unpredictable, uncontrollable, and overwhelming an individual finds their life circumstances. The higher the total score, the higher the level of perceived stress.
The findings showed that higher levels of stress were associated with a lower chance of conception for women. However, there was no association between a man's PSS score and the chance of conceiving.
On average, PSS scores at the start of the study were around one point higher among women than men.
Women with PSS scores of at least 25 were 13 per cent less likely to conceive than women with PSS scores under 10. The link was even stronger among women under 35 years old and among those who had been trying to conceive for no more than two menstrual cycles before joining the PRESTO study, compared to women who had been trying for three or more cycles before enrolling.
If higher levels of stress are causing lower odds of conception, then the researchers suggest that a small proportion of this association could be due to decreased intercourse frequency and increased menstrual cycle irregularity.
"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, the study's lead author.