New research suggests that the way baby girls develop in the womb may affect whether or not they develop polycystic ovarian syndrome (PCOS) as adults and the severity of the symptoms if they do.
This major population study examines maternal factors during pregnancy and their impact on the subsequent development of PCOS, and is the first to reconcile previous conflicting research on the developmental origins of the syndrome.
Dr Michael Davies, senior research fellow at the Research Centre in Reproductive Health at the University of Adelaide, Australia, told the 21st annual conference of the European Society of Human Reproduction and Embryology: "Our research suggests that, during pregnancy and birth, there are several different factors working through different pathways that are implicated in the overlapping and varying symptoms of PCOS that emerge in the offspring's later life".
"Existing research has already established links between foetal growth restriction, postnatal growth and metabolic disorders such as diabetes in adulthood. The idea that events in very early life can have an enduring, complex and important influence on subsequent disease is referred to as developmental programming, and this research theme has been applied to PCOS recently. Different studies have produced conflicting evidence that shows that large babies grow to become heavier adults with polycystic ovaries, but that the most severe symptoms of PCOS are associated with growth restriction as a foetus."
"Our research examines the relationship between symptoms of PCOS in adulthood and foetal conditions in women born in a major hospital in Adelaide in the 1970s. Our findings support the proposition that there is an inter-generational growth path leading to menstrual irregularity, while, at the same time, other symptoms may be one of number of consequences of restricted foetal growth."
Dr Davies and his team are studying a group of young women born between 1973 and 1975. They went back to maternity hospital records and first traced the mothers so that they could then contact and interview the daughters. So far they have interviewed 544 women who were born between 1973 and 1974 and who are aged between 30 and 32 at present.
They took a medical history of the young women and compared it with information about their births, including birth weight, placental weight, and weight of their mothers at their last clinical examination before giving birth.
Dr Davies said: "Symptoms of PCOS were relatively common. One in five women had more facial and/or body hair than normal, and one in four reported menstrual irregularity of greater than four days. Five per cent of women reported that they had an existing diagnosis of PCOS.
"We examined maternal weight in late pregnancy, birth weight and placental weight in relation to the symptoms of PCOS, or an existing or putative diagnosis of PCOS. Compared with their counterparts, young women without a diagnosis of PCOS but with irregular periods were heavier at birth, with larger placentas, and they tended to have mothers who were heavier in late pregnancy. In contrast, women with an existing diagnosis of PCOS tended to have birth weights that were, on average, 196g lighter than women without PCOS and smaller placentas.