Characteristics of hypertension in pregnancy. A retrospective study of 261 consecutive cases.

During the period 1969-73, 0.3% of 17 000 unselected non-diabetic pregnancies in our hospital were complicated by severe pre-eclampsia, 0.6% by mild pre-eclampsia and 0.6% by hypertension in pregnancy. Records from affiliated maternity centres and the hospital regarding these 261 women were studied and pertinent data assembled for comparison with 260 matched normotensive pregnancies. Instrumental deliveries were more common in all types of hypertensive pregnancy, with a 35% frequency of caesarean section in severe pre-eclampsia compared with fewer than 5% for controls. Significantly longer hospitalization and increased perinatal mortality were observed in hypertensive pregnancies, most pronounced in severe pre-eclampsia. The combination of high blood pressure and proteinuria was associated with the greatest risk for premature birth, low infant weight and perinatal mortality. The overall incidence of hypertensive disorders in pregnancy was relatively low, 1.5%, but these women counted for a significant proportion of obstetric complications requiring hospitalization and instrumental delivery.