DIAGNOSTIC ULTRASOUND - EARLY DETECTION OF FETAL NEURAL TUBE DEFECTS

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 56  (6) , 705-710
Abstract
In 366 patients identified as at risk for a fetal neural tube defect (NTD) before the 24th wk of pregnancy, 64 had an abnormal fetus. The abnormalities included anencephaly (39), open spinal defect (17), closed spinal defect (2), encephalocele (1) and a miscellany of other abnormalities (5). An ultrasound examination prior to diagnostic amniocentesis positively identified all anencephalic fetuses, the fetus with the encephalocele and 15 of the 19 fetuses with spina bifida. The spinal defects in 3 of the 4 remaining fetuses were demonstrated at a 2nd examination. Since both amniotic fluid .alpha.-fetoprotein (AFP) assays and ultrasound examination give false results in the diagnosis of NTD, the importance of using 2 independent diagnostic techniques is stressed. In patients with elevated levels of maternal serum AFP, a careful ultrasound examination, in addition to identifying the majority of cases associated with an abnormal fetus, provided a good explanation for the elevation in over half of the remainder. More than half the patients (40/69) who underwent amniocentesis because of raised maternal serum AFP levels had an abnormal fetus.