An imbalance in hormones that regulate the size of blood vessels may be the key to understanding a potentially dangerous problem that afflicts about one in every 12 expectant U.S. mothers, researchers reported recently in the Journal of the American Medical Association.
The problem is preeclampsia, a condition of late pregnancy in which the woman's blood pressure rises and her tissues retain abnormal amounts of fluid. Left untreated, it can lead to eclampsia, which can kill mother or child.
Researchers compared 134 women who developed preeclampsia with 139 similar pregnant women who did not.
Levels of a hormone that makes blood vessels expand tended to drop in the preeclampsia women weeks before the effects were detected, according to the findings.
The drop caused an imbalance in the ratio of PGI-M to another hormone, called TX-M, which makes blood vessels constrict and causes blood pressure to rise, said researchers led by Dr. James Mills of the National Institute of Child Health and Human Development.
Past research indicated aspirin might help prevent preeclampsia, but when tried on a large group of women it failed to show much benefit.
Future efforts to try to prevent preeclampsia should instead target regulating PGI-M to put the hormones back in balance, the researchers said.