Congenital abnormalities in newborns of consanguineous and nonconsanguineous parents.

The aim of this study was to determine the types, patterns, and frequencies of congenital anomalies among newborns of both consanguineous and nonconsanguineous parents in southern Iran. From 9526 consecutive pregnancies observed, 9623 newborns resulted (9431 singleton and 95 sets of multiple gestation). There were 7261 newborns from nonconsanguineous parents and 2362 (24.5%) babies from consanguineous marriages. Of the total pregnancies, 1.54% resulted in malformed children (1.53% of singleton and 2.1% of multiple gestations). The incidence of congenital abnormalities in newborns of nonconsanguineous parents was 1.66% as compared to 4.02% for newborns of the consanguineous group. Major and multiple malformations were found to be slightly more common in the consanguinous group. Prematurity, prenatal mortality rate, and congenital abnormalities were more common in the consanguineous group. Probably the closer the familial relationship of the parents, the greater the chances of congenital abnormalities.