There are, broadly, three stages of high blood pressure in pregnancy: High blood pressure is relatively common in pregnancies in the United States, occurring in 6 to 8 percent of all pregnancies—and of those, about 70 percent occur in first-time pregnancies. Women with pre-existing high blood pressure are more likely to encounter certain complications than women without high blood pressure. However, some women develop high blood pressure during pregnancy; this is called gestational hypertension.
In the most severe cases of high blood pressure in pregnancy, preeclampsia or toxemia of pregnancy develops, which can threaten the lives of both mother and fetus by harming the mother’s kidneys and other organs.
In the most severe cases of preeclampsia, a condition called eclampsia emerges; this condition can cause the mother to go into a coma, and can prove harmful or fatal to both mother and child.