Maternal serum alpha-fetoprotein levels in pregnancies among black and white women with fetal open spina bifida: a United States collaborative study

Spina bifida is a birth defect characterized by the abnormal development of the nerve tube. The defect prevents the bone structures housing the spinal cord from closing, leaving the nerves completely or partially exposed. A measurement of alpha-fetoprotein (AFP) in the mother's blood can be used to screen for many types of fetal birth defects, particularly those caused by neural tube abnormalities. AFP level cutoffs are used to determine which fetuses are at risk for neural tube defects. Open spina bifida, where the spinal cord is exposed, is associated with high AFP in the mother's blood. However, higher AFP levels have been found in pregnant black women without fetal abnormalities. To see if the AFP levels differ between black and white pregnancies, 146 pregnancies associated with open spina bifida were evaluated. The duration of the pregnancy was calculated from the last menstrual period. Black pregnant women with pregnancies complicated by fetal spina bifida had higher maternal AFP levels then white women. Therefore, a correction for race must be included to insure an equally sensitive test for pregnant women at risk for fetal abnormalities. (Consumer Summary produced by Reliance Medical Information, Inc.)