The effect of consanguinity on fertility, reproductive loss and developmental disorders were studied in 156 consanguineous marriages in comparison with 221 non-consanguineous marriages. Although fertility was greater (P less than 0.05) in consanguineous than in non-consanguineous marriages, the number of living children were approximately equal in both groups, on account of increased child mortality in the former (P less than 0.05). The frequencies of abortion and stillbirth were (also) approximately equal in both groups. Developmental anomalies were significantly more frequent (P less than 0.001) among the offspring of consanguineous parents. These results indicate the continued presence of deleterious genes in this population, in spite of the practice of consanguinity over many generations.
PIP: The effect of consanguinity on fertility, reproductive loss, and development disorders were studied in South India. The population investigated included 377 unselected mothers who, along with their children, were followed up longitudinally. Each mother was interviewed regarding consanguinity, details of reproductive performance, and death of any offspring. Marriages were classified as unrelated or between uncle and niece, between first cousins, between first cousins once removed, between second cousins, between second cousins once removed, and between third cousins. Among the 377 marriages, 156 (41.4%) were consanguineous and 221 (58.6%) were nonconsanguineous. Consanguinity was more prevalent among Hindus than among Muslims or Christians. The mean and standard deviation in the age of women were similar in all age categories at the time of the study, but the numbers of pregnancies and live births were higher in consanguineous than in nonconsanguineous unions. The mean number of living children were not significantly different in the 2 groups. Although the intrauterine wastage showed no significant difference between the 2 groups, extrauterine loss of life, especially the death rate of children, was higher in the consanguineous marriages. The causes of death in the nonconsanguineous group were diptheria, tuberculosis meningitis, acute nephritis, convulsive disorder, and brain abscess. The causes of death in the consanguineous group were measles with complications, gastroenteritis, pyogenic meningitis, whooping cough, convulsive disorder, undiagnosed fever, burns, and undiagnosed illness with persistent vomiting. In regard to developmental anomalies, in only 1 instance was the condition unequivocally due to autosomal recessive inheritance. In the majority of the remaining cases the disorders were polygenic or multifactorial in origin. The frequency of developmental anomalies was significantly more frequent among the children of consanguineous parents.