Maternal serum-alpha-fetoprotein measurements as an early indicator of low birth-weight.

In a prospective trial of 4224 pregnancies, 103 women had serum-alpha-fetoprotein (A.F.P.) above 2-3 times the median value for their stage of gestation. 10-7% of these delivered infants with birth-weights less than 2-5 kg. This was significantly greater than the rate of 4-2% for low-birth-weight infants in the general population. At higher multiples of the median serum-A.F.P. value the proportion of pregnancies leading to low-birth-weight infants was even greater. It is suggested that early identification of pregnancies with high risk of premature delivery may be an important corollary of maternal serum A.F.P. screening.