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Lithium Breastfeeding — MRCPsych Paper B MCQ

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HardPerinatal PsychiatryLithium BreastfeedingMRCPsych Paper B

A 32-year-old woman with bipolar I disorder has remained well only with lithium after alternative maintenance treatments were ineffective. She has delivered a healthy, full-term infant and wishes to breastfeed exclusively. The local perinatal service can provide specialist follow-up. Which statement most accurately reflects current UK advice?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Breastfeeding is not routinely recommended; if pursued, it requires an individual specialist decision and strict clinical and biochemical infant monitoring.

Explanation lettering: B = shown as A · A = shown as B · D = shown as C · C = shown as D

Lithium enters breast milk in variable and potentially clinically significant amounts, while neonatal renal elimination is vulnerable to impairment during dehydration or infection. NICE does not ordinarily encourage breastfeeding during lithium treatment, and UK product information lists breastfeeding as contraindicated. More recent UK specialist medicines advice permits it only exceptionally for a healthy, full-term infant following individual risk–benefit assessment, specialist supervision and strict monitoring. This includes infant lithium concentrations, renal and thyroid function, feeding, weight gain and signs of toxicity. Maternal dose reduction alone does not remove the need for infant monitoring (C), and timing feeds cannot reliably prevent exposure (D). Clinical observation alone is insufficient (A), and healthy term status reduces but does not eliminate risk (E).

Reference: NHS Specialist Pharmacy Service, Treating bipolar disorder during breastfeeding, lithium section, 2023 (updated 2024): https://sps.nhs.uk/articles/treating-bipolar-disorder-during-breastfeeding/