Guidance based on the AEMPS Summaries of Product Characteristics, e-lactancia and SEFAC.
It does NOT replace the pharmacist's professional judgement or a medical consultation.
In pregnancy and breastfeeding the decision has to be individualised. Always check
CIMA and
e-lactancia, or your own
national medicines agency. See our
clinical content policy.
Look up a medicine
By active ingredient or brand. For example: paracetamol, ibuprofen, Tylenol, warfarin, Synthroid…
Quick checks:
How to read the traffic light
Safe
Compatible or first choice. Use at the usual therapeutic doses.
Caution
Weigh benefit against risk. Look for a safer alternative where one exists, and monitor.
Avoid
Contraindicated, or high risk in that trimester or while breastfeeding. Change the drug or refer.
Why this question gets answered differently
It is the question that makes people at the counter most uncomfortable, and with good reason: there are two patients, the evidence is usually limited because trials are not run in pregnant women, and both over-caution and under-caution have a cost.
The commonest mistake is not authorising something unsafe — it is advising against by default. A mother who stops her treatment out of fear, or who gives up breastfeeding because "someone said it was better not to", usually loses more than she would have from the drug. Many poorly controlled chronic conditions — asthma, epilepsy, hypothyroidism, depression — carry a greater risk to the pregnancy than the treatment that controls them.
The professional answer is almost never a bare yes or no. It is which option within that therapeutic class has the most experience of use, and what to watch for.
What changes with timing
Pregnancy
The trimester matters. The first is organogenesis and the most sensitive to structural effects; in the third the concern is mainly the effect on labour and on the newborn. The same drug can be rated differently depending on when it is used, so asking how many weeks along the patient is is not a minor detail.
Breastfeeding
Different variables carry the weight here: how much drug actually passes into milk, whether it is absorbed orally by the infant, and how old the baby is. A newborn and a one-year-old do not handle the same exposure in the same way, and premature babies are the most sensitive group.
Practical measures that genuinely help: take the medicine straight after a feed so the peak falls in the longest interval, choose the drug within the class with the shortest half-life and least transfer into milk, and prefer topical or inhaled routes over systemic ones where the indication allows it.
What to ask, and when to refer
- Weeks of gestation, or the infant's age, including whether the baby was premature.
- What the treatment is for, and whether it is short-term or long-term. A three-day course and an indefinite treatment are not weighed the same way.
- What else is being taken, supplements and herbal products included: herbal medicine in pregnancy and breastfeeding is far less studied than medicines, and "natural" does not mean safe.
- Whether anything has already been stopped without advice. It happens constantly, and it is usually the real problem to solve.
Refer to the doctor or the midwife for long-term treatments, when the indication is unclear, when there is significant underlying disease, or when the available information is not enough. Referring is not the same as not answering: it can come with an explanation of why this should not be settled at the counter.
A note on where this data comes from
The reviewed dataset behind this page was built in Spain, against the Summaries of Product Characteristics published by the Spanish Medicines Agency (AEMPS) and e-lactancia (APILAM). Pharmacology and the safety data travel; packaging does not:
- Brand names are shown for the UK and the US where the medicine is marketed there. Where the field is empty, it usually is not.
- Some entries are regional. Metamizole (dipyrone) is widely used in Spain and Latin America and is marketed in neither the UK nor the US. Acenocoumarol is the vitamin K antagonist used in Spain; its entry covers warfarin too, since the embryopathy is a class effect — and is literally named after warfarin.
e-lactancia is written by APILAM in Spain but publishes in English as well, and it is the most complete free reference on breastfeeding compatibility there is.
Sources
- CIMA — AEMPS. Official Summaries of Product Characteristics, pregnancy and lactation sections. Prevails over any result from this tool.
- e-lactancia.org — APILAM. The reference for breastfeeding compatibility by active ingredient, available in English.
- Our clinical content policy (in Spanish).
Guidance intended to support professional practice. It does not replace assessment by a doctor or midwife, or the pharmacist's judgement.
Frequently asked questions
Which sources does this tool use?
The official Summaries of Product Characteristics held by the AEMPS (CIMA), e-lactancia (APILAM), Pediamécum, BOT-PLUS from the Spanish General Council of Pharmacists and Spanish clinical guidelines. When a drug is not in the reviewed dataset, the entry is generated by AI from those same sources and is labelled as such.
How do I read the traffic light?
Green (safe) = first choice, or safe at therapeutic doses. Amber (caution) = weigh benefit against risk, offer an alternative where possible, and monitor. Red (avoid) = contraindicated or high risk in that trimester or while breastfeeding.
Does it replace a pharmacist or a doctor?
No. The information is for guidance. Decisions in pregnancy and breastfeeding must be individualised with the responsible clinician and the pharmacist. The official sources are the Summary of Product Characteristics and e-lactancia.org.
Can I search by brand name?
Yes. UK and US brands (Tylenol, Advil, Nurofen, Zoloft, Synthroid, Prozac, Coumadin, Ventolin…) and the commonest Spanish ones are both matched to the active ingredient. If a brand is not recognised, type the active ingredient.
Are the brand names the same in my country?
Brand names are shown for the UK and the US where the medicine is marketed there. Some drugs in the dataset — metamizole, for instance — are available in neither. The active ingredients and the underlying safety data are international; availability and licensed indications are not.
What about NSAIDs during pregnancy?
Both the AEMPS (2020) and the FDA (2020) advise avoiding NSAIDs such as ibuprofen or naproxen from week 20, because of the risk of oligohydramnios and premature closure of the fetal ductus arteriosus. Before week 20, the lowest dose for the shortest time, and only if essential. Paracetamol (acetaminophen) is the first-choice analgesic and antipyretic in any trimester.