First‐ and early second‐trimester oligohydramnios—a predictor of poor fetal outcome except in iatrogenic oligohydramnios post chorionic villus biopsy

Whereas a well‐known association exists between oligohydramnios and renal agenesis, renal dysplasia, urinary tract obstruction and intrauterine growth retardation in the second half of pregnancy, the causes and prognosis of early oligohydramnios are less known. Twelve cases of first‐ and early second‐trimester oligohydramnios were detected out of 5000 fetal screenings for malformation detection. Two out of these 12 cases occurred in patients who had undergone chorionic villus sampling, two were associated with premature rupture of membranes, six were associated with fetal cardiac malformations and two cases were idiopathic. Whereas ten out of 12 cases ended in intrauterine fetal death, spontaneous or therapeutic abortions, in the two cases which developed after chorionic villus sampling the oligohydramnios was self‐limiting and these two pregnancies ended in term deliveries of normal, healthy neonates. It may be concluded that oligohydramnios in the first half of gestation bears a poor fetal prognosis except in cases where it follows chorionic villus sampling.