[Frequency of multiple neonatal malformations in Pelotas, Rio Grande do Sul, Brazil, and associated socio-demographic factors].

This study aimed to estimate the frequency and to correlate the possible causal agents and monitor the occurrence of multiple neonatal malformations in Pelotas, Rio Grande do Sul, Brazil. The study included all births from 1990 to 2002 in the local maternity hospitals with birth weight > 500 g. Each newborn presenting a malformation (case) was assigned a live matched neonate (control) without any malformation and of the same sex. A database was established by filling out the ECLAMC-MONITOR forms, 1982 edition, tabulated with SPSS. Statistical analysis used Student t and chi2. During the study period, 71,500 children were born, of whom 0.11% presented multiple malformations. Significant results were found for birth weight, twin births, parents' ethnic background, paternal age, and number of previous abortions and stillbirths. In Pelotas, the proportion of newborns with malformations during the study period was 1.37%. Of these, 8.1% presented multiple malformations, predominantly in females and in births occurring during the winter.