Can I Take Aspirin When Pregnant?

Aspirin in pregnancy is a topic that often causes confusion, because the answer depends entirely on the dose. Standard over-the-counter aspirin (usually 300mg) should not be taken in pregnancy without medical advice. However, low-dose aspirin (75mg to 150mg daily) is actively prescribed by doctors for certain pregnant women — particularly those at increased risk of pre-eclampsia. Here is what you need to know.

Quick Answer

Aspirin in pregnancy: Low-dose aspirin (75–150mg) is sometimes prescribed in pregnancy for specific medical reasons. Do NOT take standard over-the-counter aspirin (300mg) as a painkiller during pregnancy without first speaking to your GP or midwife.

Table of Contents

1. Is Aspirin Safe in Pregnancy?
2. Low-Dose Aspirin: When It Is Prescribed
3. NHS Guidance
4. Safe Pain Relief Alternatives
5. Frequently Asked Questions

Is Aspirin Safe in Pregnancy?

Standard-dose aspirin (300mg) — sold over the counter as a painkiller — is not recommended during pregnancy, particularly in the third trimester. At full doses, aspirin belongs to a class of medicines called NSAIDs (non-steroidal anti-inflammatory drugs). NSAIDs can affect kidney development in the baby if taken regularly in the second trimester, and in the third trimester they can cause premature closure of the ductus arteriosus — a blood vessel in the baby's heart that must remain open until birth. They can also increase bleeding risks around the time of delivery.

Low-dose aspirin (75–150mg) works differently. At this dose it acts primarily as an antiplatelet agent — it makes the blood slightly less sticky — rather than as a painkiller or anti-inflammatory. This property makes it useful for certain pregnancy complications and it is prescribed routinely in these contexts.

Always consult your GP, midwife, or pharmacist before taking any medication during pregnancy, including medicines you have taken safely before.

Low-Dose Aspirin: When It Is Prescribed

Risk factors for pre-eclampsia that may lead to a prescription for low-dose aspirin include:

• A previous pregnancy affected by pre-eclampsia
• Kidney disease, diabetes (type 1 or type 2), high blood pressure, or autoimmune conditions such as lupus or antiphospholipid syndrome
• Carrying twins or more
• Being a first-time mother with additional risk factors such as obesity, age over 40, or a family history of pre-eclampsia

Low-dose aspirin may also be prescribed to women with antiphospholipid syndrome (sometimes called sticky blood syndrome) to reduce the risk of pregnancy loss and other complications.

If you have been prescribed low-dose aspirin by your GP or midwife, it is safe and important to take it as directed. Do not stop taking it without speaking to your healthcare team first.

NHS Guidance

If you have been assessed as being at higher risk of pre-eclampsia, your midwife or GP will discuss low-dose aspirin with you at or around your booking appointment. The decision is based on an individual risk assessment and follows NICE guidance.

Always tell your pharmacist you are pregnant before buying any over-the-counter medicine, including aspirin.

Safe Pain Relief Alternatives

• Paracetamol (at the standard recommended dose) is the painkiller of choice in pregnancy and can be used throughout all three trimesters when needed
• Non-medication approaches — rest, a warm (not hot) bath, hydration, and gentle stretching can help with many common pregnancy aches
• Ibuprofen and other NSAIDs — these should be avoided in pregnancy unless specifically prescribed; they are particularly discouraged after 20 weeks
• Codeine-containing products — only if prescribed by a doctor; not recommended for self-treatment in pregnancy

If pain is severe or persistent, or if you have a headache that does not respond to paracetamol, speak to your midwife or GP rather than trying additional over-the-counter products.

Frequently Asked Questions

Try not to worry. Taking a standard aspirin tablet or two in very early pregnancy before you knew you were expecting is unlikely to cause harm. The risks associated with aspirin primarily relate to regular use over a sustained period, particularly in the later stages of pregnancy. Mention it at your booking appointment so it is on your notes, and contact your GP or midwife if you have concerns.

Can I buy aspirin over the counter while pregnant?

Pharmacists are trained to advise on medicines in pregnancy. Always tell the pharmacist you are pregnant before purchasing any over-the-counter product — this includes aspirin, ibuprofen, cold and flu remedies, and herbal products. A pharmacist can advise whether what you want to take is appropriate or suggest a safer alternative. For pain relief, they will generally recommend paracetamol as the first choice.

Is low-dose aspirin the same as regular aspirin?

Low-dose aspirin (75mg or 150mg tablets, sometimes called junior aspirin or dispersible aspirin) contains the same active ingredient as standard aspirin tablets (300mg) but at a much lower dose. At low doses, aspirin acts as an antiplatelet medicine rather than a painkiller. You should not substitute standard aspirin for low-dose aspirin — they are not interchangeable for pregnancy use. If you have been prescribed low-dose aspirin, use only the dose and formulation specified by your healthcare team.

Your midwife or GP is your best point of contact for any questions about medicines during pregnancy — always check before taking anything new.

This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider.

Last reviewed: June 2026

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• Pregnancy Vitamins
• Foods to Avoid in Pregnancy