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Peanut allergy and progestogen-only pill excipients — DFSRH MCQ

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EasyAllergyPeanut allergy and progestogen-only pill excipientsDFSRH

A 34-year-old woman requests an oral contraceptive 10 weeks after delivery. She is breastfeeding and has migraine with aura, so prefers an oestrogen-free method. Because of rotating shifts, she values the 12-hour missed-pill window of a desogestrel progestogen-only pill and declines long-acting contraception. She has had peanut-induced anaphylaxis requiring intramuscular adrenaline. She has no history of reaction to contraceptive hormones, takes no interacting medication and plans to remain abstinent for the next week. Which is the most appropriate management?

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

Reveal the answer and explanation

Correct answer: E — Start desogestrel 75 micrograms daily using a formulation verified to be soya-free

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

Her breastfeeding status and migraine with aura favour an oestrogen-free method, while her need for a 12-hour missed-pill window supports desogestrel rather than a traditional progestogen-only pill. The allergy issue is formulation-specific, not an intrinsic contraindication to desogestrel. FSRH advises checking for allergy to pill constituents because some desogestrel preparations contain soya and may cross-react in people allergic to peanuts. Lovima contains soybean oil, and its UK SmPC lists known peanut or soya allergy as a contraindication. A verified soya-free desogestrel formulation therefore meets both her contraceptive and allergy requirements. A is incorrect because the product-specific contraindication should be followed despite the low protein content of refined oil. B is incorrect because supervised exposure does not make administration of a contraindicated formulation appropriate. C is unnecessarily restrictive: peanut allergy does not contraindicate desogestrel itself, and norethisterone has a shorter missed-pill window. D is unnecessary because a safe formulation can be selected by checking its excipients; formal soya testing is not required before prescribing a product without soya. Her planned abstinence also covers the initial two-day precaution required when a desogestrel pill is started at this postpartum interval.

Reference: FSRH Guideline: Progestogen-only Pills (August 2022; amended April 2026) — https://www.fsrh.org/Common/Uploaded%20files/documents/fsrh-ceu-clinical-guideline-progestogen-only-pills-aug22-amended-11july-2023-.pdf Lovima 75 microgram film-coated tablets — Summary of Product Characteristics (23 December 2025) — https://www.medicines.org.uk/emc/product/12736/smpc Zelleta 75 micrograms Tablets — Summary of Product Characteristics (7 September 2020) — https://www.medicines.org.uk/emc/product/9572/smpc