Incidences and types of malformations in newborn infants.

The incidence of fetal malformations in a teaching hospital was determined by prospective study of 10,454 consecutively born infants. One or more major malformation was detected in 424 (4-1%) and one or more minor malformation was detected in 680 (6-5%). Major malformations were more common in stillborn infants (14-1%), in those who died in the neonatal period (36-7%) and in those who were small for dates (8-6%). Small for dates infants were the only group with a significant increase in the incidence of minor malformations (9-7%). The most common major malformations involved the genital organs (17-8%), limbs (14-2%), heart (11-4%) and central nervous system (10-6%). The most common minor malformations involved the skin, hair and nails (67-3%), limbs (7-7%) and genital organs (5-5%). Small for dates infants should be carefully examined to exclude major and minor malformations.