Medication Safety in Pregnancy: What's Safe, What to Avoid

This guide provides general reference information based on current NHS, MHRA, and RCOG guidance. It is not a substitute for personalised medical advice from your GP, midwife, or pharmacist — who know your individual circumstances, medical history, and the specific balance of risks and benefits for you.

If you are unsure whether a medication is safe for you in pregnancy, ask your pharmacist or GP before taking it. Pharmacists can advise without an appointment and are an excellent resource for OTC medication questions in pregnancy. If you are already taking a prescribed medication and have become pregnant, do not stop it without discussing with your prescriber — for many conditions, stopping abruptly is more dangerous than continuing.

Five principles to know before reading this guide

The default is caution — not prohibition

Most medications haven't been formally tested in pregnant women, not because they're dangerous, but because pregnant women are excluded from clinical trials. 'Insufficient data' is different from 'known to be harmful.' Your GP or pharmacist can help weigh the balance of known risks against the risk of leaving a condition untreated.

Untreated illness has risks too

Avoiding all medication is not automatically the safest choice. High fever, severe infections, uncontrolled depression, and chronic conditions all carry real risks for the pregnancy and baby. The question is always: what is the risk of this medication versus the risk of not treating?

Timing in pregnancy matters enormously

Weeks 4–12 are the window when major organs form — the period of greatest vulnerability to teratogenic effects. Some medications cautioned in the first trimester are routinely used in the second. Third-trimester risks are often different again, relating to fetal physiology rather than organ formation.

'Natural' does not mean safe

Many herbal remedies, supplements, and essential oils are assumed safe because they're natural — some are not. High-dose vitamin A, raspberry leaf tea before term, and certain herbal preparations have documented concerns. Apply the same scrutiny to unlicensed natural products as to prescribed medications.

Tell your midwife and GP everything you're taking

Your maternity team needs a complete picture — including OTC medications, supplements, herbal remedies, and anything taken before pregnancy. Some interactions only matter in combination, and your notes should reflect everything you are taking.

✓ Generally considered safe ⚠ Use with caution / discuss first ✗ Avoid in pregnancy 🚨 Specialist input essential

💊 Pain Relief 🤧 Colds, Flu & Fever 🔥 Heartburn & Indigestion 🤢 Nausea & Vomiting 🦠 Antibiotics 💙 Mental Health Medications 🧴 Skin & Topical Treatments 💊 Supplements & Vitamins ☕ Alcohol, Caffeine & Other Substances

💊 Pain Relief (5)

Paracetamol (Calpol, Panadol)⚠ Use with caution

Use lowest effective dose for shortest time

The first-line choice for pain and fever in pregnancy — used for decades and considered the safest available analgesic. However, recent observational research (including a 2021 consensus statement in Nature Reviews Endocrinology) has raised concerns about prolonged use being associated with neurodevelopmental effects and possible impact on fetal reproductive development. The MHRA has not changed its guidance — still 'lowest effective dose for shortest period' — but the picture is no longer as straightforwardly 'safe' as once presented. Use it for genuine pain and fever. Don't take it continuously over multiple days without a clinical reason, or routinely 'just in case'.

Ibuprofen, Nurofen, Advil (NSAIDs)✗ Avoid

Avoid throughout — substitute paracetamol

Specifically contraindicated in pregnancy — not merely cautioned. Many people don't realise ibuprofen is in a different category from paracetamol. In the third trimester, NSAIDs can cause premature closure of the ductus arteriosus (a vital fetal blood vessel), leading to pulmonary hypertension in the newborn, and can reduce amniotic fluid (oligohydramnios). Even in the first and second trimesters, NSAIDs are associated with increased miscarriage risk and are not recommended. If you need an analgesic: paracetamol.

Low-dose aspirin (75–150mg, prescribed only)✓ Generally safe

Safe and recommended if prescribed for pre-eclampsia

Prescribed low-dose aspirin is safe and recommended by NICE for high-risk pregnancies to reduce the risk of pre-eclampsia. This is entirely different from standard-dose aspirin (300mg+) used as a pain reliever, which should be avoided. If your GP or midwife has prescribed low-dose aspirin: continue taking it. Do not start it independently for pain relief.

Codeine, co-codamol⚠ Use with caution

Short-term only, avoid near term — prescription only

Occasionally prescribed for short-term use when paracetamol alone is insufficient. Avoid in the first trimester if possible. Near delivery, codeine can cause neonatal opioid withdrawal syndrome and respiratory depression in the newborn. If prescribed, use the lowest effective dose for the shortest time and inform your maternity team.

Diclofenac, naproxen, other NSAIDs✗ Avoid

Avoid — same risks as ibuprofen

All non-steroidal anti-inflammatory drugs carry the same pregnancy risks as ibuprofen. If you are prescribed one of these for a pre-existing condition, discuss with your GP before continuing in pregnancy.

🤧 Colds, Flu & Fever (7)

Flu vaccination✓ Generally safe

Recommended — any trimester

Strongly recommended throughout pregnancy. Influenza carries significantly higher risks in pregnant women — increased hospitalisation, preterm birth, and serious illness. The inactivated flu vaccine is safe at any stage of pregnancy and also provides some protection to the baby in the first months of life before they can be vaccinated themselves.

Paracetamol for fever✓ Generally safe

Appropriate — treat fever promptly

Treating high fever in pregnancy matters — sustained high fever in the first trimester has been associated with neural tube defects. Paracetamol is the recommended treatment. Use the lowest effective dose and do not leave a significant fever untreated.

Decongestants (pseudoephedrine, phenylephrine)✗ Avoid

Avoid — use saline nasal spray instead

Oral decongestants including pseudoephedrine (Sudafed) and phenylephrine have vasoconstrictive effects and are not recommended in pregnancy, particularly in the first trimester. Saline nasal spray is a safe and often effective alternative for nasal congestion.

Antihistamines — chlorphenamine (Piriton)⚠ Use with caution

Short-term only — discuss with pharmacist

Chlorphenamine is the most studied antihistamine in pregnancy and is cautiously considered acceptable for short-term use for allergy symptoms, itching, or nausea. It causes drowsiness. Use only if clearly needed and discuss with your pharmacist first.

Antihistamines — loratadine, cetirizine⚠ Use with caution

Loratadine cautiously preferred — discuss first

Neither is licensed for use in pregnancy, but loratadine has a reasonable safety record and is often the antihistamine considered most acceptable for allergic rhinitis and hayfever. Cetirizine is less well-studied. Discuss with your GP or pharmacist before taking either regularly.

Cough syrups⚠ Use with caution

Check ingredients — ask pharmacist

Simple linctus (glycerin-based) is safe. Avoid cough syrups containing codeine, pseudoephedrine, or significant alcohol. Many OTC cough medicines contain combinations that are not recommended in pregnancy — read the label carefully or ask a pharmacist to check a specific product.

Throat lozenges (Strepsils, Difflam)✓ Generally safe

Most are low-risk

Most throat lozenges are considered low-risk as minimal active ingredient is absorbed systemically. Avoid preparations containing iodine or high-alcohol sprays. Honey and lemon preparations are fine.

🔥 Heartburn & Indigestion (3)

Gaviscon (alginate antacids)✓ Generally safe

First-line — safe throughout pregnancy

Gaviscon and other alginate-based antacids work locally in the stomach with minimal systemic absorption. Considered safe throughout pregnancy and are the standard first-line recommendation for pregnancy heartburn.

Calcium carbonate antacids (Rennie, Tums)✓ Generally safe

Safe for short-term use

Work locally and are safe for short-term use. Avoid very high quantities as excessive calcium carbonate can affect the acid-base balance.

Omeprazole, lansoprazole (PPIs)⚠ Use with caution

On GP advice — not first-line self-treatment

Proton pump inhibitors are increasingly used in pregnancy when antacids are insufficient, and the evidence does not suggest significant fetal harm. However, they should be initiated on GP advice rather than self-prescribed. At the lowest effective dose, they are routinely prescribed when heartburn is severe and unresponsive to antacids.

🤢 Nausea & Vomiting (6)

Ginger (tablets, tea, food)✓ Generally safe

Well-evidenced, safe

Good evidence for reducing mild to moderate nausea. Safe at typical dietary and supplement doses — ginger tea, ginger biscuits, ginger capsules are all fine. High-dose supplements (above 1g/day) have less safety data; food-based forms are preferable.

Vitamin B6 (pyridoxine)✓ Generally safe

Safe — a reasonable first step

Pyridoxine has evidence for reducing nausea and is included in the licensed antiemetic Xonvea. Available OTC and safe at standard doses. Often tried before prescription antiemetics.

Cyclizine⚠ Use with caution

Commonly prescribed — on GP advice

The most commonly prescribed antiemetic for nausea and vomiting of pregnancy in the UK. An antihistamine. No clear evidence of teratogenicity; limited formal trial data. Available on prescription. Considered first-line for hyperemesis gravidarum alongside rehydration.

Promethazine (Phenergan)⚠ Use with caution

Reasonable safety record — discuss with pharmacist

Another antihistamine antiemetic, available OTC. Used in pregnancy with a reasonable safety record. Causes significant sedation — discuss with a pharmacist before using.

Ondansetron⚠ Use with caution

For severe cases — prescription only, discuss with GP

Increasingly used for hyperemesis gravidarum when first-line treatments haven't worked. Earlier studies raised concerns about cleft palate; subsequent larger studies have been more reassuring. RCOG supports its use for severe nausea where the severity of illness outweighs theoretical risk. Prescription only — not for self-treatment.

Metoclopramide⚠ Use with caution

Short-term only — prescription only

Occasionally prescribed for severe nausea not responding to other treatments. Short-term use considered acceptable; not recommended for prolonged use.

🦠 Antibiotics (8)

Penicillin (amoxicillin, ampicillin)✓ Generally safe

Safe — first-line for many infections

Penicillin-based antibiotics are considered safe throughout pregnancy and are first-line treatment for many bacterial infections including UTIs, chest infections, and dental infections. Widely used with a good safety record.

Erythromycin, azithromycin (macrolides)✓ Generally safe

Safe — preferred in penicillin allergy

Safe in pregnancy and commonly used when penicillin allergy is present. Erythromycin is used in specific pregnancy protocols (PPROM). Azithromycin also considered safe. Clarithromycin has slightly less safety data; erythromycin or azithromycin are generally preferred.

Cefalexin (cephalosporins)✓ Generally safe

Safe — commonly used

Cephalosporin antibiotics are considered safe in pregnancy. Good safety record and commonly prescribed for UTIs and other infections.

Nitrofurantoin (Macrobid)⚠ Use with caution

Safe in first/second trimester — avoid from 36 weeks

First-line treatment for UTIs in pregnancy — safe in the first and second trimesters. Should be avoided from 36 weeks onwards due to risk of neonatal haemolytic anaemia. If prescribed in late pregnancy, check the gestation with your GP.

Trimethoprim⚠ Use with caution

Avoid first trimester — discuss with GP thereafter

A folate antagonist — first-trimester use has been associated with neural tube defects. Avoid in the first trimester. Discuss with your GP if needed in later pregnancy — it may be appropriate in some cases with adequate folic acid supplementation.

Metronidazole (Flagyl)⚠ Use with caution

Caution in first trimester — use when clinically needed

Used for bacterial vaginosis, dental infections, and some other conditions. Can be used in pregnancy when clinically necessary. Avoid high-dose IV regimens in the first trimester. Standard courses are generally acceptable under GP guidance.

Tetracyclines (doxycycline, oxytetracycline)✗ Avoid

Avoid — causes fetal tooth and bone staining

Tetracyclines deposit in developing bone and teeth, causing permanent discolouration of baby teeth and potential bone effects. Avoid throughout pregnancy and while breastfeeding. Safe alternatives are almost always available.

Fluoroquinolones (ciprofloxacin, levofloxacin)✗ Avoid

Avoid — safer alternatives available

Associated with cartilage and joint effects in animal studies and generally avoided in pregnancy. Safer alternatives are usually available for the conditions they treat — discuss with your GP if fluoroquinolones have been prescribed.

💙 Mental Health Medications (5)

SSRIs (sertraline, fluoxetine, citalopram)⚠ Use with caution

Do not stop abruptly — discuss with GP. Sertraline preferred.

The most important message: do not stop antidepressants without discussing it with your GP or psychiatrist first. Stopping SSRIs abruptly in pregnancy can cause withdrawal and relapse of depression — which carries its own serious risks including preterm birth, low birth weight, and impaired bonding. The risks of untreated depression in pregnancy are real. Sertraline has the most safety data and is generally the SSRI of choice in pregnancy. Paroxetine (Seroxat) has more concerns than other SSRIs and is generally avoided if alternatives exist. If you become pregnant while on SSRIs, contact your GP — but do not stop independently.

SNRIs (venlafaxine, duloxetine)⚠ Use with caution

Discuss with prescriber — switching may be considered

Less safety data than SSRIs but used when clinically necessary. Venlafaxine is associated with neonatal adaptation syndrome at higher doses. Discuss with your prescriber — options include continuing, switching to an SSRI with more data, or gradual reduction with close monitoring.

Lithium🚨 Specialist input essential

Do not stop without psychiatrist — specialist monitoring essential

Lithium is associated with a small increased risk of cardiac malformation (Ebstein's anomaly) in the first trimester and neonatal toxicity. However, stopping lithium abruptly carries a very high risk of severe relapse in bipolar disorder. Do not stop lithium without your psychiatrist's involvement. Lithium levels require more frequent monitoring in pregnancy as renal clearance increases significantly.

Benzodiazepines (diazepam, lorazepam)⚠ Use with caution

Avoid routine use — seek GP advice before stopping

Avoid in the first trimester if possible (cleft palate association in early studies). Near term, neonatal withdrawal syndrome is a concern. Short-term use in acute crises may be necessary under medical supervision. Do not stop regular benzodiazepines abruptly without medical guidance.

Antipsychotics (quetiapine, olanzapine)⚠ Use with caution

Do not stop without specialist input

The risks of stopping antipsychotic medication in pregnancy are generally higher than the risks of continuing in most cases. Specialist psychiatric supervision is essential. Some antipsychotics increase gestational diabetes risk — additional glucose monitoring may be recommended.

🧴 Skin & Topical Treatments (7)

Topical hydrocortisone 1%✓ Generally safe

Short-term, limited area use — safe

Mild topical corticosteroid — safe for short-term use on limited skin areas. Avoid applying to the face, breasts, or large areas of the body. Routine use for eczema is acceptable under GP guidance.

Azelaic acid✓ Generally safe

Preferred topical acne treatment in pregnancy

Considered the safest topical acne treatment available in pregnancy. Minimal systemic absorption. Suitable for mild to moderate acne throughout pregnancy.

Sunscreen — mineral (zinc oxide, titanium dioxide)✓ Generally safe

Preferred sunscreen in pregnancy

Mineral sunscreens have minimal skin absorption and are considered safest in pregnancy. Chemical sunscreens (oxybenzone) have evidence of systemic absorption — switching to mineral-based is a reasonable precaution, though evidence of harm from chemical sunscreens is not established.

Stronger topical steroids (betamethasone, clobetasol)⚠ Use with caution

Under GP guidance — weakest effective preparation

Moderate to potent steroids should be used with caution and under GP guidance in pregnancy. Systemic absorption is possible when used on large areas. Use the weakest preparation effective for the shortest time.

Benzoyl peroxide⚠ Use with caution

Limited data — azelaic acid preferred

Minimal systemic absorption. Generally considered low-risk in pregnancy for spot treatment use, but limited safety data. Azelaic acid is preferred as the safer alternative for acne.

Salicylic acid⚠ Use with caution

Low-concentration skincare acceptable — avoid high-dose treatments

Low concentrations in face washes and toners (0.5–2%) are considered low-risk as systemic absorption is minimal. High-dose salicylic acid treatments — wart removers, chemical peels, high-concentration acne treatments — carry the same risks as systemic aspirin and should be avoided.

Retinoids (tretinoin, adapalene, isotretinoin)✗ Avoid

Avoid — teratogenic. Isotretinoin: seek urgent advice if pregnant.

Retinoids are vitamin A derivatives and are teratogenic. Topical retinoids (tretinoin, adapalene) used in skincare and acne treatment should be discontinued in pregnancy. Oral isotretinoin (Roaccutane) is absolutely contraindicated — it causes severe birth defects in a high proportion of exposed pregnancies and is subject to a mandatory Pregnancy Prevention Programme. If you are taking isotretinoin and discover you are pregnant, seek urgent advice from your prescriber and GP immediately.

💊 Supplements & Vitamins (10)

Folic acid 400mcg✓ Generally safe

Essential — start before conception if possible

Recommended from before conception until 12 weeks to reduce the risk of neural tube defects. 5mg daily is recommended for higher-risk women (previous NTD pregnancy, certain medications including valproate and methotrexate, BMI above 30, diabetes). Ideally start before a positive test.

Vitamin D 10mcg (400IU)✓ Generally safe

Recommended for all pregnant women

Recommended throughout pregnancy. Most people in the UK have insufficient vitamin D, particularly in winter. Available free on Healthy Start for eligible women. 10mcg (400IU) daily is the standard dose; higher doses may be recommended by your GP if deficiency is confirmed.

Iron supplements✓ Generally safe

Safe and commonly needed — as prescribed

Routinely prescribed when haemoglobin or ferritin indicates deficiency. Safe throughout pregnancy. Take on an empty stomach if tolerated, or with a small amount of food if it causes nausea. Vitamin C alongside iron enhances absorption. Common side effect: dark stools and constipation.

Omega-3 / fish oil (pregnancy-specific)✓ Generally safe

Safe — use pregnancy-specific formulations

Safe in pregnancy and associated with fetal brain and visual development. Use products specifically formulated for pregnancy — these have had vitamin A removed, unlike cod liver oil. 200–300mg DHA per day is typically recommended.

Vitamin C, vitamin E (standard doses)✓ Generally safe

Safe at standard doses

Safe at standard supplement doses throughout pregnancy. High-dose supplementation (above 1,000mg vitamin C or above 400IU vitamin E) has not been shown beneficial and very high doses carry theoretical risks.

High-dose vitamin A (above 700mcg retinol)✗ Avoid

Avoid — teratogenic at high doses

Vitamin A is teratogenic at high doses and associated with fetal malformations. Avoid supplements containing more than 700mcg of retinol daily. Do not take cod liver oil in pregnancy — it is high in vitamin A. Beta-carotene from fruit and vegetables is safe.

Cod liver oil✗ Avoid

Avoid — high in vitamin A

Cod liver oil is high in vitamin A (retinol) and should not be taken in pregnancy. Use an omega-3 supplement specifically formulated for pregnancy instead.

Evening primrose oil✗ Avoid

Avoid — no proven benefit, possible risk

Sometimes marketed for cervical ripening near term. Evidence for benefit is not established, and there is some evidence of possible complications. Avoid throughout pregnancy.

Raspberry leaf tea⚠ Use with caution

Avoid before 36 weeks — discuss with midwife if near term

Sometimes used from 36–37 weeks to prepare for labour. Evidence is limited. Avoid before 36 weeks. If you wish to use it near term, discuss with your midwife first.

Herbal supplements generally⚠ Use with caution

No safety data for most — avoid unless specifically considered safe

Most herbal supplements have not been tested in pregnancy and have no safety data. 'Natural' does not mean safe — many plant compounds are bioactive. As a general rule, avoid herbal supplements not specifically known to be safe in pregnancy unless discussed with your midwife or GP.

☕ Alcohol, Caffeine & Other Substances (5)

Nicotine replacement therapy (patches, gum)✓ Generally safe

Safer than smoking — recommended if needed to quit

NRT is significantly safer than continuing to smoke and is actively recommended by NHS Stop Smoking services for pregnant women. Patches are preferable to gum or inhalators in pregnancy as they provide steadier nicotine delivery. If you cannot stop smoking without support, NRT is the safer choice.

Caffeine⚠ Use with caution

Limit to 200mg/day — track all sources

NHS and RCOG guidance recommends limiting caffeine to 200mg per day. This is roughly one mug of filter coffee, two mugs of instant coffee, two to three cups of tea, or five cans of cola. Caffeine crosses the placenta; the fetus cannot metabolise it efficiently. Above 200mg/day is associated with increased risk of low birth weight and miscarriage. Remember caffeine is present in tea, cola, energy drinks, and chocolate — not just coffee.

Alcohol✗ Avoid

No safe level — avoid completely

There is no established safe level of alcohol in pregnancy. Alcohol crosses the placenta freely. Heavy drinking causes Fetal Alcohol Syndrome; the risk from lighter drinking cannot be quantified as zero. NHS guidance is to avoid alcohol completely throughout pregnancy, with the first trimester being the period of greatest developmental vulnerability.

Smoking✗ Avoid

Avoid — stop at any gestation, seek support

Smoking in pregnancy is associated with miscarriage, placental abruption, preterm birth, low birth weight, stillbirth, and sudden infant death syndrome. Stopping at any point in pregnancy reduces risk. NHS Stop Smoking services provide free support; NRT is safe and recommended.

Cannabis (including CBD)✗ Avoid

Avoid — including CBD products

Cannabis is associated with low birth weight, preterm birth, and neurodevelopmental effects in children. Both THC and CBD — including CBD oils and products — should be avoided in pregnancy. There is no established safe level.

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Medication not found in this guide

Try a shorter search or a different spelling. For medications not listed here, ask your pharmacist or GP — there is no such thing as a question too small about what you can take in pregnancy.

Where to Get Advice

Your pharmacist is the most accessible resource for medication questions in pregnancy — no appointment needed. Any community pharmacist can advise on whether an OTC medication is appropriate in pregnancy, suggest safer alternatives, and flag interactions with other medications you are taking.

Your GP or midwife should be consulted for any concerns about prescribed medications, or before starting any medication you are uncertain about. For mental health medications in particular, decisions about continuing, switching, or tapering should always involve your prescriber.

The UK Teratology Information Service (UKTIS) provides specialist advice to healthcare professionals about medication safety in pregnancy and produces detailed monographs on individual medications — your GP can access these. The consumer site medicinesinpregnancy.org is produced by UKTIS and is a reliable source of patient information.

The Specialist Pharmacy Service (sps.nhs.uk) publishes NHS guidance on medication safety in pregnancy and breastfeeding that is accessible to patients.

If you have taken something and are now concerned

If you have taken a medication before realising you were pregnant, or have inadvertently taken something on the avoid list, contact your GP or midwife to discuss. In many cases the risk will be very low — but they can help you assess the specific situation rather than leaving you to worry. Most accidental single exposures do not result in harm, but a clinical conversation is always worthwhile.

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