[Detection of fetal neural tube defects by analysis of alpha-1-fetoprotein in maternal serum. An evaluation concerning the years 1984 and 1985.]
Opsporing van foetale neuraalbuisdefecten door middel van de bepaling van alpha-1-foetoproteine in maternaal serum. Een evaluatie over de jaren 1984 en 1985
RIVM Report 199101003
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%.