Stress can reduce the chances of conceiving.

The findings revealed on Thursday suggest that reducing stress can help women get pregnant.

Prior to the study, the relationship between stress and pregnancy was only a theory due to lack of scientific evidence.

The findings were based on the study of the ovulation cycles of 274 British women aged 18 to 40. The researchers took saliva samples from the volunteers, all of whom were trying to get pregnant. The levels of specific hormones in the saliva were then measured.

The alpha-amylase was considered the stress indicator and those with high levels of this hormone had 12 percent reduction in getting pregnant every ovulation cycle, according to Dr. Germaine Buck Louis, a director at the USNIH's National Institute of Child Health and Human Development in Maryland, USA. In contrast, women with the lowest concentration of alpha-amylase in their saliva had higher chances of conceiving, she said.

Louis also observed that stress levels often increased when a woman gets upset for failing to conceive.

With the findings published in the journal Fertility and Sterility, the next mission is to find a way to lessen or eliminate stress in women to make them pregnant. Louis ruled out alcohol and tobacco in relieving stress because these substances also reduces the chances of pregnancy.