Changes in alpha-fetoprotein levels in a case with multiple congenital anomalies

Abstract

A chromosomally normal women, who previously lost an infant with meningomyelocele and hydrocephalus, with a chromosomally normal husband, had normal alpha fetoprotein (AFP) levels in both amniotic fluid and maternal serum at about 19 weeks gestation. At 34 weeks, suspected hydramnios was confirmed clinically and radiographically; the latter showed no evidence of hydrocephalus. AFP levels at 36 weeks showed 224 ng/ml in maternal serum and 1249 ng/ml in amniotic fluid. Maternal serum rose from the 25th-19th percentile, and amniotic level was 5-fold greater than normal (200 ng/ml). At 39 weeks, abnormal AFP values of 258 and 1500 ng/ml for maternal serum and amniotic fluid, respectively, were measured. Though AFP patterns did not suggest an open neural tube defect (higher 19-week values were expected), spontaneous labor at 39 weeks resulted in a 1930-gm female with multiple congenital abnormalities. These AFP assays suggest: 1) that signaling of abnormalites other than neural tube defects is a valid use of AFP assays; 2) that the slope rather than single point values should be used in interpreting AFP results; 3) that assays in both amniotic fluid and maternal serum should be obtained and interpreted simultaneously in screening for birth defects; and 4) that sequential assays should be performed even in the presence of initially normal findings.