835: How accurate is the prenatal diagnosis of a fatal fetal abnormality?

Abstract

The objective of the study was to examine the outcomes of prenatally diagnosed fatal fetal abnormalities in a high volume European center. We examined both termination rates and spontaneous fetal loss. Data was gathered prospectively in a large tertiary referral center over 5 years from 2013-2017 inclusively. We defined fatal fetal abnormalities as conditions where death was predicted before or shortly after birth. We included all cases of prenatally diagnosed Trisomy 13, Trisomy 18, Triploidy, Renal agenesis, limb body wall complex and anencephaly. Baseline demographic and delivery details were recorded on an anonymized computerized database, these data are subject to continuous audit. The gestation at diagnosis, associated anomalies and the nature of diagnostic tests were recorded. Outcomes including termination of pregnancy (TOP), miscarriage, stillbirth and neonatal death were recorded. There were a total of 44,750 deliveries in the study period. There were 1836 congenital anomalies diagnosed in the study period including 163 cases (8.8%) of fatal abnormalities. There was an incidence therefore of 0.3% or 1 in 333. 67% women chose a termination of pregnancy following the diagnosis. There was an incidence of 9.5% for second trimester miscarriages and 11.7% for stillbirths. The total fetal loss rate prior to delivery in those that did not undergo termination was 65%. There were 35% neonatal deaths with only 1 surviving to 5 weeks. All cases of prenatally diagnosed fatal fetal abnormalities in the study resulted in death, the diagnosis was therefore accurately made. This study was based in a unit where termination of pregnancy required travel to another jurisdiction during the study period, allowing a unique opportunity to observe the natural history. In this study in 99% of cases babies did not survive beyond 4 weeks of life. 65% died before birth and 35% died in the early neonatal period. Accurate outcome data is beneficial when counselling those who choose to continue their pregnancy or in settings where there is limited access to termination of pregnancy.