Why is aspirin recommended during pregnancy?
There is evidence to suggest that aspirin can reduce the risk of developing pre-eclampsia. This is a condition which affects an average of between two and eight women in every 100 and can affect both your health (high blood pressure, protein in your urine and, rarely, seizures) and your baby (slow growth, the risk of stillbirth).
Do I need to take aspirin?
If you have one of the following high-risk factors, you will be offered aspirin during your pregnancy:
- Hypertensive disease during a previous pregnancy (high blood pressure, pre-eclampsia, or eclampsia)
- Chronic Hypertension (high blood pressure prior to becoming pregnant)
- Chronic Kidney Disease
- Type 1 or Type 2 Diabetes
- Autoimmune disease, such as Systemic Lupus Erythematosus (SLE) or antiphospholipid syndrome
- You’ve previously had a baby affected by Fetal Growth Restriction (a smaller baby than expected)
- You’ve previously had a stillbirth
- Low Pregnancy Associated Plasma Protein (PAPP-A) – a biochemical marker in your blood, found as part of the first trimester screening test you have between 11 and 14 weeks.
If you have two of the following moderate risk factors, you will be offered aspirin during your pregnancy. Your midwife or obstetrician will discuss which risk factors apply to you:
- This is your first pregnancy
- IVF pregnancy
- Your last pregnancy was more than 10 years ago
- You are aged 40 or over
- There is a history of pre-eclampsia in your family
- Multiple pregnancy (you’re having twins/ triplets, etc)
- On booking in, you have a Body Mass Index (BMI) of 35 or more
How much aspirin do I need to take?
You will be prescribed 150mg of aspirin (two 75mg tablets) to take once a day, from 12 weeks of pregnancy. We recommend you take it with food to reduce the risk of indigestion and in the evening, so it is absorbed better.
In some cases, this may not be appropriate, and a lower does (75mg) may be used at your Consultant’s discretion.
It doesn’t matter if you occasionally miss a dose, and you should continue to take the aspirin until your baby is born.
Please note, we do not recommend taking high dose aspirin – more than 150mg a day – during pregnancy.
Is it safe to take aspirin in pregnancy?
There’s no evidence to suggest that aspirin will cause any harm to your baby, either in the short or long term, although it is an unlicensed use of the medicine. If you require further information, please discuss this with your Midwife or Doctor.
When you should not take aspirin
Do not take these tablets if you:
- Are allergic to aspirin, NSAIDs – which includes those when attacks of asthma, angioedema, urticaria, or rhinitis have been precipitated by aspirin or any other NSAID
- Suffer from gout or have in the past
- Have a stomach ulcer or have had problems with ulcers in the past
- Suffer from hemophilia or any other bleeding condition
What happens next?
At your booking visit, you will have been asked a number of questions by your midwife. If, as a result of this information, it has been identified that you need to take aspirin during pregnancy, a prescription will be provided from the antenatal clinic at the hospital.
If you need more, please contact the Antenatal Day Unit or your Community Midwife.
Aspirin is available to buy over the counter at most supermarkets. Most packs have an information sheet inside advising that it is not taken during pregnancy unless advised to do so by a doctor. This is a legal requirement, placed on the manufacturers to protect pregnant women from accidentally taking any medication without being medically advised that it is safe and necessary.
We will continue to monitor you throughout your pregnancy. We will test your blood pressure and urine and your antenatal visits, to check for signs of pre-eclampsia. How frequently we monitor you at appointments will depend on your individual management plan for your pregnancy.
Date of issue: April 2023
Review period: March 2026