Postnatal depression affects as many as 1 in 5 women four-six weeks after giving birth and 7% of new mothers suffer from major depression. A study of 100 women by researchers at the University of California, Irvine found that there was a link between high levels of a hormone called corticotropin-releasing hormone (CRH) and postnatal depression. CRH is normally produced in tiny amounts by the hypothalamus in response to stress but pregnant women's placentas produce 100 times as much. The hormone is thought to prepare pregnant women for childbirth but the levels drop immediately afterwards and the 'withdrawal' symptoms can affect the endocrine system. 12 of the 16 women who had high levels of the hormone 25 weeks into their pregnancy went on to develop postnatal depression. The researchers hoped that a blood test for the hormone could be used to pick up women at risk of developing postnatal depression.
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