Congenital Malformations in the New Born in Bombay: Part II

1. From a prospective series of 29,925 pregnancy terminations, 24,248 pregnancy terminations of the registered group were taken up for the present study. 2. Malformation rates in single births of the seven Hindu groups, Muslims and Christians have been compared. The malformation rate is not significantly different in these groups and the rate lies between 1% to 2%. 3. The effect of maternal age and parity has been observed on the incidence of malformation. A trend towards an increase in the malformation rate with an increase in the maternal age and also a noticeable increase in the rate in 1st parity was observed though statistical significance could not be established. 4. Recurrence risks have been calculated for few malformations and compared with those of other populations where available. Though the material is scanty, it shows a marked rise in the specific malformation recurrence risks. 5. Cases of simply inherited conditions (achondroplasia, albinism, icthyosis congenita and microcephaly) have been discussed in detail. Their gene frequency estimates together with their standard errors have been calculated from data on different populations and compared. No statistical significance was found for any of the population differences. 6. Malformations that occur in multiple births have been described and the malformation rate in twin births (1.44%) has been found to be nearly the same as that in single-births (1.40%). It was noted that there was no concordance with respect to malformation in any of the like-sexed twin pairs.