Major birth defects among infants with Down syndrome in Alexandria, Egypt (1995-2000): trends and risk factors.

We evaluated the hypothesis that the trisomy 21 genome interacts with environmental factors during early pregnancy to increase the risk for birth anomalies in Down syndrome infants in Alexandria, Egypt. A case-control study on 514 infants with confirmed Down syndrome was carried out from 1 July 1995 to 30 June 2000. Genetic, biological, environmental and reproductive factors were analysed. Multiple logistic regression analysis showed the following factors to be independently associated with increased risk of congenital heart diseases among Down syndrome patients: parental consanguinity, maternal parents' consanguinity, mother's antibiotics use in pregnancy, oral contraceptive use and diabetes in the mother. Fever in the mother during pregnancy was associated with increased risk of gastrointestinal anomalies.