The pre-eclampsia risk rose from 5.2 percent to 7.0 percent among women who had treatment for infertility. Among those who had three or more miscarriages, the pre-eclampsia risk increased to 8.5 percent – though it appeared that having only one or two miscarriages didn’t raise the risk of hypertension during pregnancy. And among women who experienced both multiple miscarriages and infertility treatment, the pre-eclampsia rate rose to 13.1 percent.
Pre-eclampsia results from a malfunctioning placenta, though why the placenta malfunctions is unknown. In later pregnancy, the placenta has difficulty in fulfilling its role in conveying oxygen and nutrients from the mother’s blood to the fetus’. When this happens, the mother’s circulatory system starts to work harder to get blood to the placenta, raising her blood pressure and causing pre-eclampsia. If the condition is untreated, it can progress to eclampsia, which can endanger the life of both mother and fetus. The only effective treatment is delivery of the baby and placenta.
For unknown reasons, having previous normal pregnancies sharply lowers the risk of pre-eclampsia – about 50 percent, in fact. But this protective effect disappears among women with repeated miscarriages. Therefore, the study suggests that common causal factors linked to the placenta’s development and function may be present in infertility, repeated miscarriages and pre-eclampsia.