A UK study suggests that stress can reduce the chances of a woman conceiving during the fertile mid-phase of her monthly cycle.
A total of 274 healthy women , aged between 18 and 40, and who were trying to become pregnant, provided saliva samples which were tested for levels of cortisol (a stress hormone) and adrenalin (the latter via an indicator known as alpha-amylase). Tests were conducted for six menstrual cycles or until pregnancy if sooner.
The results showed that those women with high adrenalin levels across the fertile window of their cycle, were less likely to conceive. In fact, the chance of conception for women with the highest levels, was about 12% lower than that for women in the bottom quarter of the adrenalin level range. The authors of the study comment that these findings support the use of relaxation techniques to increase the chances of becoming pregnant.
(Stress Reduces Conception Probabilities across the Fertile Window: Evidence in Support of Relaxation. Fertility & Sterility, June 2011.)