Pre-eclampsia, a spectrum of hypertensive disorders that complicate pregnancy, affects between 2 and 6 percent of healthy women in the United States and up to 14 percent of mothers-to-be worldwide. Typically diagnosed after the 20th week, the condition can cause various health problems, such as reducing the baby's supply of oxygen and nutrients (potentially resulting in low birth weight) and raising the mother's risk of cardiovascular disease.
Previous research has suggested that physical activity can reduce a woman’s risk of pre-eclampsia. And a study presented last week at the Physiology of Cardiovascular Disease: Gender Disparities conference in Jackson, Miss. supports these earlier findings - showing that exercising during the early stages of pregnancy stimulates the expression of two proteins thought to play a role in blood vessel health, which may protect mothers-to-be from developing high blood pressure.
In the study, researchers used an animal model to study exercise and pregnancy at the molecular level. They separated rats into two groups and allowed one group to exercise voluntarily for six week prior to and during pregnancy. Throughout the exercise period, researchers monitored running times and distances weekly. The other group served as the control group and did not exercise. Late in the animals' pregnancies, researchers collected tissue samples for analysis and, as reported by Medical News Today, the researchers found:
... the rats in the exercise group had higher levels of a circulating protein called vascular endothelial growth factor (VEGF) than those in the control group. VEGF and a pregnancy specific version of the protein called placental growth factor (PlGF) are important because not only do they stimulate the development of new blood vessels, they also maintain normal vessel function which in turn promotes good cardiovascular health.
According to [study author Jeffrey Gilbert, PhD,] finding increased VEGF in the exercise group has important implications for understanding, and perhaps preventing, preeclampsia. He noted that clinical and experimental studies have found that high levels of a protein called sFlt-1 can bind up the mothers' circulating levels of PlGF and VEGF and can lead to preeclampsia.
The researchers also saw that when VEGF increased, endothelial function increased. The endothelium is a thin layer of cells that line the inside of blood vessels. It reduces turbulence in blood flow, which allows blood to be pumped further with each heartbeat, thus taking stress off the heart.
Researchers say they plan to further investigate whether stimulating these proteins with exercise before pregnancy or early during pregnancy can effectively lower a woman's risk for preeclampsia.