Few humans experience more psychological trauma than women who endure repeated miscarriages. A team of 20 researchers at Israel’s Weizmann Institute of Science sought to answer the question so often asked: Why?
The researchers wanted to determine whether miscarriage survivors show any olfactory differences from a control group of women. They knew to analyze scent processing because many mammals’ olfactory systems are intertwined with reproduction. For example, pregnant mice will miscarry when exposed to the scent of an unfamiliar male who did not father the pregnancy. This is called the Bruce effect—some theorize that it is a response to the availability of a more fit male.
The researchers’ hunch played out. They found that when presented with the t-shirts of men, most of the 33 women who had experienced repeat miscarriages could identify their husbands’ shirts, while most of the control group could not. The differences between the groups were