Survival of infants with neural tube defects in Western Australia 1966-1990.

Abstract

To investigate the survival of infants with neural tube defects in Western Australia from 1966 to 1990, cases of neural tube defects were ascertained from multiple sources. Survival of infants with anencephaly, spina bifida, and encephalocoele was examined separately, and four birth cohorts were compared: 1966-1972 (when most surviving infants were actively treated), 1973-1979 (a period of stringent application of selection criteria for treatment), 1980-1985 (some relaxation of selection criteria), and 1986-1990 (further relaxation of selection criteria). There was an increase in terminations of pregnancies affected with anencephaly over the study period, and a fall in the proportion of both liveborn and stillborn infants with anencephaly. Most liveborn infants (76.4%) died in the first 24 hours, and none survived longer than 5 days. Most infants with encephalocoele (76.4%) were liveborn, and survival was poorest in the 1973-1979 cohort, although the difference in survival across cohorts just failed to attain a formal level of significance. For spina bifida, there was an increase in terminations of affected pregnancies over the study period. Survival of liveborn infants with spina bifida was poorest in the 1973-1979 cohort, and greatest in the most recent cohort. These improvements in survival are likely to be the result of relaxation of selection criteria for treatment, improvements in treatment and, to a lesser extent, selective termination of affected pregnancies.