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
Women who have suffered unexplained repeated pregnancy loss (uRPL) have altered perceptions and brain responses to male body odours, in comparison to those with no history of uRPL, suggests a new study published today in eLife.
The results could lead to urgently needed answers for many women who experience repeat miscarriage with no clear underlying explanation.
Around 50% of human conceptions and 15% of human pregnancies result in miscarriage, but only a limited number of these can be explained. Body odour has been linked to many aspects of healthy human reproduction — such as synchrony of menstruation between women who live together, and the influence of body odours of breast-feeding women on the timing of ovulation and menstruation in others.
“Given that sense of smell is associated with human reproduction, we hypothesised that it may also be related to disorders of human reproduction,” explains lead author Liron Rozenkrantz, who