Abstract

Aims: To ascertain why 19.6% of pregnancies in which a fetal renal anomaly has been detected fail to produce a surviving child, and whether antenatal diagnostic accuracy has altered since specialised fetal medicine units were established in 1995.

Methods: An analysis of deaths was conducted among fetuses and babies with a congenital abnormality in the urinary tract notified to the Northern Region Congenital Abnormality Survey (NorCAS). There were 560 deaths among 2857 cases with an anomaly in the urinary tract delivered between 19 February 1984 and 21 March 2000.

Results: Renal anomaly was the cause of death in 323 (57.7%) cases. Excluding 10 which were not screened, 126 (60%) of 210 pre-1995 had been suspected antenatally and 81 (78.6%) of 103 post-1995. No abnormality had been suspected in 39 (18.6%) cases pre-1995 and four (3.9%) post-1995. Postnatal death occurred in 89 (41.4%) pre-1995 and in 13 (12%) post-1995. There were 209 cases of death caused by anomalies in other systems but with a renal anomaly present, of which 66 (31.6 %) were chromosomal and 36 (54.5%) had a horseshoe kidney. Of the cases with a horseshoe kidney, 56.3% had a chromosomal anomaly.

Conclusions: The antenatal diagnosis of renal anomalies which cause death did not improve significantly in the second period of this study. However, the number of false positive antenatal diagnoses and the number of postnatal deaths were significantly lower and the number of pregnancy terminations were significantly higher. This reduced the risk of delivering a live baby with an unexpected fatal renal anomaly.