It found that women were less likely to conceive when they showed elevated levels of a particular stress-related substance called alpha-amylase. It's released when the nervous system produces compounds that initiate a type of stress response.
The findings in the journal Fertility and Sterility suggest that doctors need to identify appropriate ways to help women reduce stress when they are trying to get pregnant.
Authors say techniques worth investigating could include, meditation, biofeedback, yoga and boosting social support.
