Prenatal exposure to environmental tobacco smoke can be decisively linked to:

• A. Congenital anomalies
• B. Sudden infant death syndrome
• C. Spontaneous abortion
• D. Low birth weight

Answer: (B)

Exposure to tobacco smoke during pregnancy disrupts the fetus’s oxygen delivery and autonomic regulation, creating a vulnerability after birth. Carbon monoxide from cigarette smoke binds fetal hemoglobin more readily than oxygen, causing chronic hypoxia, while nicotine constricts placental vessels and alters fetal blood flow and heart rate. These combined effects can impair brainstem development and the infant’s ability to respond to command of breathing and arousal, which are critical defenses against SIDS. Epidemiologic studies show a clear, dose‑dependent increase in SIDS risk with maternal smoking during pregnancy, making this association one of the strongest and most consistently observed modifiable risk factors for SIDS. Although prenatal tobacco exposure is also linked to low birth weight and other outcomes, the link to sudden infant death syndrome is the most robustly emphasized in this context.