Four cases of pregnancy with low estrogen production due to placental enzymatic deficiency.

4 cases of normal pregnancies associated with low estriol excretion and resulting in healthy infants are described, in which by in vitro studies on the placentas a steroid 3-sulfatase deficiency was found in 3 cases and a lack of activity of the aromatizing system was found in the 4th case. A reduced activity of the aromatizing system was also shown in one of the cases affected by steroid 3-sulfatase defect. The placental 3 beta-hydroxysteroid dehydrogenase, delta 4,5-isomerase system was measured in 3 cases and results were normal. The repetition of the specific lack of steroid 3-sulfatase was observed in 2 successive pregnancies of the same patient (case T.C.). It is interesting to note that, at variance with other reports, this patient delivered 2 fetuses, both female.