English Abstract In 1984 and 1985 a total of 3386 sera from pregnant
women were analysed for alpha fetoprotein aiming to detect fetal neural tube
defects. After elimination of sera with unknown or incorrect gestational
age 3313 sera could be evaluated. Clinical post-partum results were
reported in 77% of the cases. Of 99 pregnancies with a serum
AFP-concentration higher than the internationally accepted 97 percentile in
56 cases (57%) a defect or other clinical condition was found, such as
missed abortion, intra-uterine fetal death and feto-maternal transfusions.
Two of three anencephaly and all 4 open spina bifida cases yielded elevated
AFP-levels. In one twin pregnancy with one of the foetus with anencephaly,
the AFP-value however was just below the borderline for twins. The
sensitivity of the AFP-determination for the detection of open fetal neural
tube defects turned out to be 87.5% with a positive predictive value of
7.1%. If all other defects and conditions yielding AFP-elevation were taken
into account the sensitivity was 16% with a positive predictive value of
49.5%.
