Objective: To evaluate the contemporary usefulness of amniotic alfa-fetoprotein (AFP) measurements in the prenatal diagnosis of neural tube defects (NTDs).
Methods: Two retrospective studies were performed. In Part I we reviewed 77 cases with elevated levels of amnioitic AFP. We examined whether elevated amniotic AFP corresponded with a fetal diagnosis, and which fetal conditions it revealed. In Part II we reviewed 24 cases of prenatally diagnosed meningomyelocele (MMC). We examined how this condition was revealed.
Results: In Part I 24 of the 77 fetuses had malformations. 92 % of these were detected on ultrasound. In 8 % of the cases the AFP level led to further investigations, and the malformations were revealed on a follow-up sonography. The malformations included 9 multiple malformations (more than two organ systems involved), 6 MMCs, 4 anencephalis, 1 cleft platelet, 1 omfalocele, 1 hydrops foetalis, 1 trisomi 18 and 1 malformations of the urinary tract. In Part II all patients were diagnosed prenatally with MMC. The condition was exclusively detected on ultrasound examnination. None of the women had amniocentesis before the diagnostic ultrasound examination. In addition to MMC 20 cases had hydrocefalus, 2 had omfalocele, 1 had VSD and 1 had malformation of the urinary tract.
Conclusion: Ultrasound examination has become the most important method for prenatal diagnosis of NTDs. The measurment of amniotic AFP is no longer justified.