ORIGIN OF AMNIOTIC-FLUID ALPHA-FETOPROTEIN IN NORMAL AND DEFECTIVE PREGNANCIES

Abstract

Alpha-fetoprotein was determined by electroimmunodiffusion and radioimmunoassy in 109 neonatal urine samples and 94 amniotic fluid samples. The samples were obtained from newborns and from pregnancies ranging in gestational age from 20-40 wk. When .alpha.-fetoprotein values of neonatal urine and amniotic fluid were correspondingly correlated with gestational age, almost identical declining curves could be drawn. Twenty-one CSF samples from newborns ranging from 25-40 wk of gestation were similarly determined. No correlation between CSF .alpha.-fetoprotein and gestational age could be demonstrated. Fetal urine probably is the major source of .alpha.-fetoprotein in the amniotic fluid of normal pregnancy. In pregnancies associated with neural tube defects, .alpha.-fetoprotein elevation is probably not due to the leakage of CSF into the amniotic cavity.