Infants with antenatal exposure to benzodiazepines or barbiturates may develop signs of drug withdrawal at:

• A. Birth to 48 hours after birth
• B. 3 to 5 days after birth
• C. 7 to 21 days after birth
• D. 28 to 42 days after birth

Answer: (C)

Withdrawal signs after in utero exposure to benzodiazepines or barbiturates tend to be delayed because these drugs are long-acting and cross the placenta, accumulating in the fetus. After birth, the infant must clear the drug with immature liver enzymes, so levels decline slowly. As the drug is eliminated, the infant can develop withdrawal symptoms, which most commonly begin in the first week and can continue into the second week of life. This makes the 7 to 21 days after birth window the typical period for onset of signs such as irritability, poor feeding, tremors, and sleep disturbances in these infants.