Fetal polyuria and hydramnios associated with Bartter's syndrome.

The case of a woman with recurrent hydramnios in three pregnancies, from which the only surviving infant was later found to have Bartter's syndrome, is described. Analysis of electrolytes, renin activity, and aldosterone levels in amniotic fluid from this pregnancy are presented. The finding of maternal hydramnios in the present and 12 other reported cases of Bartter's syndrome suggests that increased fetal voiding is the most likely causative factor in the development of increased amniotic fluid volume. Early onset hydramnios might signify Bartter's syndrome in the offspring in families with an index case. In cases of hydramnios of unknown etiology, appropriate investigations might lead to early diagnosis and treatment of Bartter's syndrome.