Spontaneous abortion and fetal abnormality in subsequent pregnancy.

In a prospective survey neural tube defects and other congenital abnormalities were studied in the babies born to 510 mothers ascertained during pregnancy. The women were divided into two groups according to the outcome of their immediately preceding pregnancy. Those whose preceding pregnancy had resulted in a spontaneous abortion (256 women) formed the index cases; those in whom the outcome had been a normal baby (254 women) served as controls. There was a highly significant increased number of congenital abnormalities in the index cases. This may possibly be explained by the trophoblastic "rest" hypothesis and suggests that spontaneous abortions are more relevent to congenital abnormalities than has been thought.