Because of the association of preeclampsia with hydatidiform mole, and since levels of 19-hydroxyandrostenedione (19-OH-A) and androstenedione (A) are raised in hypertensive diseases of pregnancy, we compared plasma 19-OH-A and A in hydatidiform mole patients with control early pregnant women. Both steroids were significantly elevated in 27 patients with partial or complete hydatidiform moles, as compared with the levels in 36 control pregnancies at similar stages of gestation.