The Pathogenesis of Congenital Anomalies: Roles of Teratogens and Infections

Abstract

Congenital anomalies present with significant financial, social, and moral issues and questions to the family and society and are difficult to rehabilitate. In utero exposure to teratogenic agents and infection are the two most important causes of nongenetic acquired anomalies presenting at birth. Teratogens such as drugs, adverse maternal conditions, and toxins are environmental factors that cause permanent structural or functional malformations or death of the embryo or fetus. Teratogens may cause significant congenital anomalies if encountered during the organogenesis period of 3–8 weeks of fetal life, which is the stage of tissues and organs formation, whereas minor morphological and functional disorders may occur with exposure during the fetal period of first 2 weeks. TORCH group infections (toxoplasmosis, others, rubella, cytomegalovirus, and herpes) are the most serious infectious diseases during pregnancy due to the severity of possible embryo-fetal lesions. With expanding scientific knowledge and clinical experience about the association of these toxins and infections with significant, at times crippling congenital anomalies, the avoidance of exposure to pregnant mothers has become the most important part of their prevention and management.