Local anaesthetic choice in pregnancy — ORE Part 1 MCQ

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ModerateDental Pharmacology and TherapeuticsLocal anaesthetic choice in pregnancyORE Part 1

A 30-year-old at 22 weeks' gestation requires urgent restoration of a painful carious molar. She is otherwise well and concerned that local anaesthetic might harm the fetus. The tooth is restorable and can be treated with routine precautions. What is the most appropriate management?

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Correct answer: E — Use a dental local anaesthetic with vasoconstrictor such as lidocaine with adrenaline at licensed doses

The correct answer is E. Evidence demonstrates that standard local anaesthesia is safe throughout pregnancy, and 2% lidocaine with 1:200,000 adrenaline best balances safety and efficacy for pregnant patients. The misconception that local anaesthetics harm the fetus often leads to treatment delays, which cause adverse consequences including disease progression and patient distress. Adrenaline in licensed dental doses is not associated with clinically significant systemic effects in pregnancy and actually reduces systemic absorption of the local anaesthetic by improving vasoconstriction at the injection site. Option B (delay) perpetuates avoidable harm through postponement. Option A (general anaesthesia) is inappropriate and carries greater risks for both mother and fetus than local anaesthesia. Option D (omitting vasoconstrictor) removes the pharmacological benefit of reduced systemic absorption. Option C (antibiotics alone) does not address a restorable tooth or pain. At 22 weeks (second trimester), elective dental treatment is appropriately timed.

Reference: Physiology of pregnancy and oral local anesthesia considerations. PMC10315135 (systematic review); NHS Specialist Pharmacy Service: Considering interactions with local anaesthetics in dentistry (January 2025). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10315135/ and https://sps.nhs.uk/articles/considering-interactions-with-local-anaesthetics-in-dentistry/