A woman's hormonal balance can be affected by stress in several ways. For instance, under stressful conditions, an excess of cortisol can be produced by an accelerated conversion of progesterone, leading to lower levels of progesterone and oestradiol - key players in a woman's menstruation cycle. Alternatively, an excess of testosterone, progesterone and oestrogens may be secreted due to impaired cortisol control. Either condition can lead to menstrual disorders, fertility problems and more.
Studies of women undergoing in-vitro fertilisation treatment show that the most stressed-out women are 93 per cent less likely to have a baby by the end of five years compared with their more relaxed peers (Fertil Steril, 2001; 76: 675-87). In addition, in this study, women who reported feeling angry, hostile or depressed had fewer eggs to fertilise and fewer embryos to transfer.
There is also evidence that severe emotional stress during early pregnancy can cause congenital malformations. Danish researchers studying 3560 pregnancies over 12 years found stressed women were more than one-and-a-half times more likely to have a baby with a cranial neural crest deformity (Lancet, 2000; 356: 875-80).