Pre-eclampsia affects approximately 2-8% of all pregnancies worldwide, with onset of symptoms in the late second or third trimester, most commonly after the 32nd week. Some women will experience preeclampsia as early as 20 weeks, though this is rare. Preeclampsia may also occur in the immediate postpartum period.

Preeclampsia is one of the leading causes of maternal and perinatal morbidity and mortality worldwide. Nearly one tenth of all maternal deaths in Africa and Asia and one quarter in Latin America are associated with hypertensive diseases in pregnancy, a category that encompasses preeclampsia.

Preeclampsia is much more common in women who are pregnant for the first time and in women who have previously been diagosed with preeclampsia. Pre-eclampsia is also more common in women who have preexisting hypertension, diabetes, autoimmune diseases such as lupus, various inherited thrombophilias such as Factor V Leiden, renal disease, women with a family history of pre-eclampsia, obese women, women with a multiple gestation (twins or multiple birth), and women of advanced maternal age. Change of paternity in a subsequent pregnancy has also been implicated as affecting risk, except in those with a family history of hypertensive pregnancy

Eclampsia is a major complication of preeclampsia. Eclampsia affects 0.56 per 1000 pregnant women in developed countries and almost 10-30 times as many women in low-income countries as in developed countries.

Epidemiology
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