[Boston.com]

It’s a phrase that many women struggle to conceive hate to hear: “Just relax, don’t think about it so much and it’ll just happen.” But a new study suggests there may be some truth to that often unsolicited advice.
Researchers at Ohio State University collected saliva samples from 401 women ages 18 to 40 who wanted to get pregnant to test for two different stress hormones, cortisol and alpha-amylase. They then followed the women for up to a year and found that those who had high levels of alpha-amylase took, on average, 29 percent longer to conceive compared to those with low levels of the stress biomarker. Also, those with higher levels of the alpha-amylase in their saliva were twice as likely to qualify for an infertility diagnosis, meaning they were not able to get pregnant after a year of trying.
This study, published Monday in the journal Human Reproduction, adds to mounting evidence that high levels of alpha-amylase could play a role some women’s chances of conceiving. Another study published August 2010 in the journal Fertility and Sterility found nearly the same results — of the 274 women they took saliva samples from, those with the highest concentration of alpha-amylase of were 12 percent less likely to conceive within six menstrual cycles.
According to the American Society of Reproductive Medicine, chronic stress increases the production of certain hormones in the body which can either delay or completely skip the time a woman releases an egg.