Antenatal detection of placental steroid sulphatase deficiency: use of a dehydroepiandrosterone sulphate loading test.

Dehydroepiandrosterone sulphate (50 mg) was given intravenously to 15 women in the third trimester of pregnancy in which urinary oestrogen excretion was subnormal (less than 32 mumol/24 h) without recognizable clinical or therapeutic cause. In six patients, this procedure was followed by a marked increase in plasma oestradiol concentrations [mean (SD), nmol/l] before treatment: 44 (13) and 30 min after injection: 279 (31). After delivery, the placentas from all these patients showed steroid sulphatase activity in vitro (greater than 450 units). In the other nine patients, all of whom subsequently showed negligible placental steroid sulphatase activity in vitro (less than 10 units), mean plasma oestradiol concentrations increased only from 18 (9) to 26 (11) nmol/l. Changes in plasma oestradiol concentrations in late pregnancy after injection of dehydroepiandrosterone sulphate therefore readily permit identification of those patients in whom a placental enzyme deficiency is the cause of the subnormal oestrogen production. The defect was identified as steroid sulphatase deficiency by an in-vitro test of placental tissue after delivery.