Basic and Clinical Sciences (BCSE) 2025 – 400 Free Practice Questions to Pass the Exam

Cleft lip and palate are well-documented developmental abnormalities that have been associated with maternal exposure to tobacco smoke during pregnancy. Studies have shown that exposure to tobacco increases the risk of orofacial clefts, which include both cleft lip and cleft palate. The harmful substances in tobacco smoke can disrupt normal facial and dental development during critical periods of embryonic and fetal growth.

Other conditions, such as spina bifida, Down syndrome, and congenital heart defects, have different etiologies and risk factors that do not include tobacco exposure as a significant contributor. For instance, spina bifida is primarily linked to genetic factors and maternal folate deficiency, while Down syndrome is usually caused by chromosomal abnormalities (specifically trisomy 21). Congenital heart defects may arise from a complex interplay of genetic and environmental factors, but not specifically tied to tobacco smoke in the same way that cleft lip and palate are. Thus, the association of cleft lip and palate with tobacco smoke is particularly well-established in the literature, making it the correct answer.