Antenatal detection of placental steroid sulphatase deficiency by measurement of urinary 16 alpha-hydroxydehydroepiandrosterone sulphate.

A simple gas chromatographic technique for the measurement of 16 alpha-hydroxydehydroepiandrosterone sulphate in urine from pregnant women is described. An assessment was made of the effectiveness of the measurement of this oestriol precursor for the antenatal diagnosis of placental steroid sulphatase deficiency. Twenty-two patients whose pregnancies were complicated by subnormal oestrogen excretion for gestation were studied. In nine of these, where placental steroid sulphatase activity was found subsequently in vitro to be normal, the excretion of 16 alpha-hydroxydehydroepiandrosterone sulphate was less than 27 mumol/24 h. In the remaining 13 patients, in whom postnatal in vitro assay demonstrated absence of placental steroid sulphatase activity, urinary excretion of 16 alpha-hydroxydehydroepiandrosterone sulphate was 59-360 mumol/24 h. The excretion of this metabolite was below the limit of detection (20 mumol/24 h) in 30 uncomplicated pregnancies. It is concluded that urinary excretion of 16 alpha-hydroxydehydroepiandrosterone sulphate greater than 50 mumol/day or a ratio of urinary 16 alpha-hydroxydehydroepiandrosterone sulphate to urinary oestrogen greater than 2.0 correctly identifies, before delivery, those pregnancies in which fetus and placenta are deficient in steroid sulphatase activity.