RESUMO
This was a period prevalence study carried out in 4 hospitals in Baroda from October 93 to February 97 covering over 30,000 deliveries. This study, a part of the multicentric SOMDI Project, aimed at dermining the prevalence of malformations in the population and the overall risk figures for Down Syndrom (DS) as well as its maternal age specific prevalence. The hospitals chosen for the study had delivery rates such that the study in the end was expected to comprise of 50% Government i.e. poor socioeconomic strata (SES) and 50% Private sector i.e, an upper SES. Total number of births recorded were 31,775, with the Government Sector having 15,652 and the Private sector have 16,123. The total number of malformations was 651 with the overall incidence of malformation being 2.05% and the incidence the Government and private sectors being 2.57% and 1.54% respectively. The significantly lower incidence in the private sector was probably because of an upper SES and because of early detection and termination. Increasing maternal age showed a rising trend in the percentage of malformations with incidence in the age group from 15-19 years being 2.07% that at an age more than or equal to 40 being 4.92%. Still births had 6.3 times higher incidence of malformations than that in live births (10.43% in still births Vs 1.68% in live births). Malformations were found to be significantly higher in rural (3.1%) compared to urban (1.8%) populations and in children of Consanguinous (5.0%) compared to non-consanguinous marriages (2.06%). Pre terms had a significantly higher (5.6%) incidence of malformations compared to term (1.75%) babies. In male and female babies, incidence of malformations was not significantly different (2.12% and 1.75% respectively). A previous history of malformations was present in 53 incidences (out of total deliveries); out of 53, as many as 31 had a previous history of a neural tube defect (NTD) and in 2 of these there was a recurrence of NTD in this particular pregnancy. In the systemwise distribution of malformation, CNS anomalies were the most common, followed by the musculoskeletal system and gastrointestinal system. An interesting association noted was a large number of babies having a combination of midline defects viz. cleft lip and/or cleft palate and NTD and/or hyrocephalus. A total of 33 Down syndrome cases were encountered with an overall prevalence of 1.04% per 1000 and an overall risk of DS of 1 per 962 births. Maternal age specific prevalence of DS increased from 0.54/1000 at age 15-19 years to 15.6/1000 at age > 40 years. The corresponding age specific risks for DS were 1/1825 births and 1/64 births respectively.