Miscarriage & stress

Pregnant women who are stressed out during the first three weeks after conception are nearly three times as likely to miscarry, a new study finds. They measured cortisol, a stress-linked hormone. In all, miscarriages occurred in 90 percent of pregnancies in which the women had increased cortisol levels and in 33 percent of those with normal cortisol levels.
Most pregnancy losses take place in the first three to four weeks after conception.
Nepomnaschy said it's unclear why a boost in cortisol might raise miscarriage risks, but he offered a hypothesis: "The body might interpret that [increased cortisol level] as conditions deteriorating, and maybe that might trigger an abortion mechanism."

Makes sense to me.