RESUMEN
The aims of the study were to assess the prevalence of birth defects [BDs] in Ahwaz, Iran amongst the live births born between 1 Oct 2006 and 31 Oct 2007. There were a total of 4176 live births in Ahwaz during this study period. The interview included the Father and mother's date of birth, Number of gravidity, paternal smoking, maternal delivery age and the occupation of the mother and father. Out of 4176 subjects, 1.43 per 1000 live births presented with multiple anomalies. The overall occurrence of malformation among working mothers were 1.67 and 7.42 for working fathers. Parents in the occupational group 'Commerce' had the highest rates [3.83 per 1000 live births]. The frequencies of BDs in smokers were 3.5 [per 1000 live births]. The gravidity profiles showed that all three types were very close to each other. The occurrence rate of BDs increased in the maternal delivery age of 18-35 years [5.74 per 1000 live birth]. The prevalence of BDs in Southwest of Iran is comparable to those in other countries. Some of the birth defects are not diagnosed at birth and may occur later in the life