SONOGRAPHICALLY DETERMINED ANOMALIES AND OUTCOME IN 170 CHROMOSOMALLYABNORMAL FETUSES

Structural pathology and outcome were studied in 170 chromosomally abn ormal fetuses. Numerical chromosomal abnormalities were established in 158 (93 per cent) cases, of which 110 (71 per cent) represented triso mies, 30 (18 per cent) Turner syndrome, and 18 (11 per cent) triploidy . Structural chromosomal abnormalities were diagnosed in 12 (7 per cen t) cases. Gestational age at referral was significantly shorter for pr egnancies with Turner syndrome than for the other chromosomal abnormal ities. Referral before 20 weeks of gestation was mainly based on fetal structural pathology alone (92 per cent); after 20 weeks, patients we re referred because of structural pathology combined with small for ge stational age, oligohydramnios, or polyhydramnios. Referral as a resul t of suspected multiple organ pathology occurred in 73.5 per cent of p regnancies. An abnormal amniotic fluid volume was present in 59/170 (3 4.5 per cent) chromosomally affected pregnancies, i.e., oligohydramnio s in 31 and polyhydramnios in 28 cases. Birth weight was below the ten th percentile in over half of the chromosomally abnormal fetuses, exce pt for Turner syndrome. Fetal outcome was poor, with a survival rate a t 1 month of 30 per cent for trisomies which was mainly determined by trisomy 21 (14/18=77.5 per cent).