more likely to develop high blood pressure or other heart disease later in life. more research is needed to determine the long-term health effects of hypertensive disorders in pregnancy and to develop better methods for identifying, diagnosing, and treating women at risk for these conditions. even though high blood pressure and related disorders during pregnancy can be serious, most women with high blood pressure and those who develop preeclampsia have successful pregnancies. obtaining early and regular prenatal care for pregnant women is important to identify and treat blood pressure disorders. epidemiology high blood pressure problems occur in six percent to eight percent of all pregnancies in the u.s., about 70 percent of which are first-time pregnancies. in 1998, more than 146,320 cases of preeclampsia alone were diagnosed. although the proportion of pregnancies with gestational hypertension and eclampsia has remained about the same in the u.s. over the past decade, the rate of preeclampsia has increased by nearly one-third. this increase is due in part to a rise in the numbers of older mothers and of multiple births, where preeclampsia occurs more frequently. for example, in 1998 birth rates among women ages 30 to 44 and the number of births to women ages 45 and older were at the highest levels in three decades, according to the national center for health statistics. furthermore, between 1980 and 1998, rates of twin births increased about 50 percent overall and 1,000 percent among women ages 45 to 49; rates of triplet and other higher-order multiple births jumped more than 400 percent overall, and 1,000 percent among women in their 40s.