Aspirin in Pregnancy

Information for pregnant people who are prescribed Aspirin throughout their pregnancy.

What is Aspirin?

Aspirin is a known as an NSAID (a non-steroidal anti-inflammatory drug). Aspirin is often used to treat pain, fever, inflammation or prevent clot formation. 

There is evidence to show that taking low dose aspirin can help increase the function and blood flow of your placenta which provides your baby with oxygen and nutrients during your pregnancy to help them grow. 

 Why have I been advised to take Aspirin?

You have been given this leaflet as your midwife or doctor has identified that you are at a higher risk of developing a condition called Pre-eclampsia in pregnancy. 

There are a number of reasons that can make pre-eclampsia more likely. If one of the following applies to you, you will be advised to take low dose aspirin daily: 

  • high blood pressure or Pre-eclampsia in a previous pregnancy
  • autoimmune disease 
  • Chronic kidney disease
  • Chronic Hypertension
  • Diabetes Type 1 or 2
  • confirmation from the pathology lab of a placenta that was not working properly in a previous pregnancy 

If two or more of the following apply to you, you will be advised to take low dose aspirin daily:

  • BMI more than 35kg/m2
  • multiple pregnancy
  • family history of Pre-eclampsia in a first degree relative
  • first pregnancy
  • maternal age more than 40
  • more than 10 years between pregnancies

Research has investigated the benefits of taking Aspirin in pregnancy for pregnant people with the risk factors listed above. Reassuringly, this found that the use of Aspirin can reduce the risk of developing the following: 

  • hypertension (high blood pressure) 
  • Pre-eclampsia (high blood pressure and excessive protein in your urine) 
  • your baby being smaller than expected
  • giving birth to your baby prematurely (before 37 weeks) because of pre-eclampsia and small baby

How should I take Aspirin?

You should take 150mg (two x 75mg tablets) every evening (with or just after food). Do not worry if you forget to take a tablet, just take one when you remember, however make sure you only take 150mg in a 24 hour period. 

You should start taking Aspirin at 12 weeks gestation and continue daily throughout your pregnancy. 

If you are have a singleton pregnancy (one baby), please stop taking your aspirin at 36 weeks. If you are pregnant with multiples (twin or triplet pregnancy), please stop your Aspirin at 32 weeks.

Is it safe to take Aspirin in pregnancy?

  • Aspirin is generally safe in pregnancy, and there is no known link to abnormalities in the baby. Aspirin in rare circumstances can cause some side effects, for example: stomach pain or indigestion (most common) 
  • blood in your stool (rare) 
  • skin rash (uncommon) 
  • breathing difficulties (uncommon): call 999 urgently 

If you experience any side effects we advise you to contact a health care professional (eg. GP, Community Midwife, Pregnancy Assessment Unit, 111) the same day: 

What is Pre-eclampsia? 

Pre-eclampsia is a condition that only occurs in pregnancy and is thought to be caused by the placenta (afterbirth). It is a rare but can be a serious condition and is known to occur in about 1 in 16 pregnancies. 

In some cases, Pre-eclampsia may present but not cause any symptoms.  It is then detected by high blood pressure and/or protein in the urine and/or abnormal blood tests, which your midwife will check at your antenatal appointments. However, sometimes Pre-eclampsia can present with symptoms, the most common are;

  • severe headaches
  • visual disturbances, such as blurring or flashing
  • sudden swelling in your hands, face and feet
  • pain just below the ribs
  • vomiting

If you begin to experience any of these symptoms or if you are concerned speak to your community midwife or Pregnancy Assessment Unit (PAU) urgently. 

Who should not take Aspirin? 

If you have any of the conditions below we would not recommend taking Aspirin during your pregnancy:

  • active stomach ulcers 
  • bleeding disorders (antiplatelet dose) 
  • children under 16 years (risk of Reye’s syndrome) 
  • allergy to Aspirin or non-steroidal anti-inflammatory drugs (NSAIDs), such as Ibuprofen in the past
  • severe asthma

Shared Decision Making

At the Queen Elizabeth Hospital Maternity Unit, we advocate a shared decision making approach to all decisions made by our patients. This leaflet aims to give you additional information and to act as a point of reference following a discussion with your obstetrician or midwife. If you are asked to make a decision about your own care please make sure you have asked all the questions you need to ask and are given the appropriate time to do so. Some questions you might want to ask could be: 

  • What are my options? 
  • What are the pros and cons of each option? 
  • Who will support me making the decision that is the right one for me?

Contact numbers

If you have any additional queries please contact:

Community Midwife

Pregnancy Assessment Unit

24 hours 0191 445 2764

Delivery Suite

24 hours 0191 445 2150

Data Protection

Any personal information is kept confidential.  There may be occasions where
your information needs to be shared with other care professionals to ensure you receive
the best care possible.

In order to assist us to improve the services available, your information may be used for
clinical audit, research, teaching and anonymised for National NHS Reviews and Statistics.  

Further information is available via Gateshead Health NHS Foundation Trust website or by contacting the Data Protection Officer by telephone on 0191 445 8418 or by email ghnt.ig.team@nhs.net.

This leaflet can be made available in other languages and formats upon request