SECOND-TRIMESTER HYDROPS FETALIS IN PREGNANCIES AFFECTED BY HOMOZYGOUS α-THALASSAEMIA-1

Homozygous α‐thalassaemia‐1 is the commonest cause of hydrops fetalis in South‐East Asia. Ultrasonographic features of hydrops fetalis were said to be evident only after 20 weeks of gestation. We studied 111 pregnancies at risk of homozygous α‐thalassaemia‐1 at 12–14 gestational weeks and 101 pregnancies at 17–18 weeks by abdominal ultrasound examination. Ultrasonographic features of hydrops fetalis were seen in 3 out of 44 pregnancies affected by homozygous α‐thalassaemia‐1 at 12–14 weeks [7 per cent; 95 per cent confidence interval (CI) 1–19 per cent] and in 7 out of 21 affected pregnancies at 17–18 weeks (33 per cent; 95 per cent CI 15–57 per cent). In conclusion, homozygous α‐thalassaemia‐1 can cause hydrops fetalis in the early second trimester. It should constitute one of the differential diagnoses in the work‐up of second‐trimester hydrops fetalis. © 1997 by John Wiley & Sons, Ltd.