Aspirin in pregnancy

Patient Leaflets Team

  • Reference Number: HEY1046/2020
  • Departments: Maternity Services


This leaflet has been produced to give you general information about your condition.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor/midwife, but may act as a starting point for discussion. If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

Why is aspirin given during pregnancy?

Some pregnant women are at risk of developing pre-eclampsia (a serious condition which usually presents as high blood pressure and protein in the urine) and intrauterine growth restriction (when the baby is smaller than usual due to not growing at a normal rate in the womb). There is evidence to suggest that this group of women are at reduced risk of developing these conditions if they take a low dose of aspirin during their pregnancy.

Why do I need aspirin during my pregnancy?

If you have 1 of the following risk factors you will be offered aspirin during your pregnancy:

(Your midwife/doctor will indicate which risk factor(s) apply to you)

  • Hypertensive disease during your previous pregnancy
  • Chronic kidney disease
  • Autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome
  • Type 1 or Type 2 diabetes
  • Chronic hypertension
  • Low Pregnancy Associated Plasma Protein (PAPP-A) screening blood test
  • Previous Intrauterine growth restriction (IUGR) (either birth weight <2.5kg or <10th centile)
  • Previous stillbirth
  • Previous pre-eclampsia/eclampsia

If you have 2 of the following risk factors you will be offered aspirin during your pregnancy:

(Your midwife/doctor will indicate which risk factors apply to you)

  • First pregnancy
  • Pregnancy interval of more than 10 years
  • Family history of pre-eclampsia
  • IVF pregnancy
  • Age 40 years or older
  • Multiple pregnancy
  • Body Mass index (BMI) of 35Kg/m2 or more at first contact

How much aspirin do I need to take?

You will be prescribed 150mg of aspirin to take once daily (although a small number of women may be prescribed a larger dose). You should take this as soon as you receive the prescription (as this is associated with better outcomes) until the birth of your baby.

How will I receive the prescription?

Most risk factors will be identified by your midwife at your first booking appointment. The midwife will send a letter to your doctor to request the prescription which you can collect from your doctor’s surgery.

Some risk factors may be identified later in your pregnancy, for example following an ultrasound scan. If this is the case your midwife or doctor will inform you at that time and will notify your doctor in the same manner.

 Are there any contraindications to taking aspirin?

There are some rare medical conditions were aspirin would not be recommended. You doctor will advise you if this applies to you.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact:

Antenatal Clinic (01482) 382623

Community Midwives (01482) 382658 / 382742

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