Smoking in Pregnancy: Effects and Cessation

Mechanism of harm:Carbon monoxide (CO) displaces O2 on fetal hemoglobin (CO has 200× affinity for Hgb vs O2) → fetal hypoxia. Nicotine causes vasoconstriction of uteroplacental vessels → reduced placental perfusion → IUGR. Maternal effects: - Ectopic pregnancy risk: ×2 (impaired fallopian tube ciliary function) - Spontaneous abortion: significantly increased - Placenta previa: smoking associated with abnormal placentation - Placental abruption: ×2 risk - Preterm labor and PPROM: higher rates - Decreased fertility (even if patient conceives successfully) Fetal/neonatal effects: - IUGR and low birth weight (most significant — dose-dependent) - Preterm birth - SIDS (sudden infant death syndrome): 3× risk if mother smokes - Fetal breathing movement reduction (nicotine effect) - Cleft lip/palate: modest association - Neurodevelopmental: ADHD, behavioral issues in childhood Management: - Ask, Advise, Assess, Assist, Arrange (5 A's framework) - Cessation counseling: behavioral support; referral to quit lines - Pharmacotherapy: - Nicotine replacement therapy (NRT — patch, gum, lozenges): safer than smoking; preferred over no cessation - Bupropion: some use in pregnancy (limited data; benefit may outweigh risk) - Varenicline (Chantix): limited data; generally avoided...