Survival of infants with open spina bifida in relation to maternal serum alpha-fetoprotein level. Third report of the UK collaborative study on alpha-fetoprotein in relation to neural-tube defects.

Thirteen centres collaborated to determine the relation between maternal serum alpha-fetoprotein (AFP) levels and the survival and handicap of infants with open spina bifida. Data were collected on 97 pregnancies tested for maternal serum AFP at 10-24 weeks gestation which resulted in the birth of an infant with open spina bifida. Pregnancies with relatively high AFP levels were associated with decreased infant survival though the extent of handicap at 6 months was not significantly related to AFP level. The survival rate at 6 months was 13% (3/23) among infants born to women with AFP values in the highest of three groups, 32% (13/41) among women with values in the middle group and 45% (15/33) in the lowest AFP group (X2l for trend 6.48, P less than 0.01). Antenatal screening of maternal serum AFP at 16-18 weeks gestation with a cut-off level of 2.5 times the normal median would have detected about 68% of those who survived for at least 6 months compared with 79% of all open spina bifida pregnancies tested.