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Aspirin prophylaxis to prevent pre-eclampsia: the role of midwives

By Dr Cristina Fernandez Turienzo and Professor Andrew H Shennan

Hypertensive disorders of pregnancy are a serious condition globally. In this article Dr Cristina Fernandez Turienzo, Midwife Senior Research Fellow, and Prof Andrew H Shennan, Professor of Obstetrics, King’s College London, point to the use of Aspirin prophylaxis and the importance of midwives in promoting its use.


Hypertensive disorders of pregnancy (HDP), including chronic hypertension, gestational hypertension, and pre-eclampsia, are a leading cause of maternal morbidity and mortality globally (1). Chronic hypertension occurs before pregnancy or 20 weeks’ gestation; gestational hypertension (previously known as pregnancy induced hypertension) is de novo hypertension after 20 weeks’ gestation; and pre-eclampsia is the multisystem disease characterized by widespread endothelial dysfunction and often accompanied by proteinuria (2). Pre-eclampsia can lead to severe adverse outcomes (i.e. pulmonary oedema, cerebral hemorrhage, placental abruption, eclampsia) thus it is crucial to differentiate pre-eclampsia from other HDP to ensure early diagnosis and birth as no other treatment is available once pre-eclampsia has developed (3).

For many years, low dose aspirin has been used during pregnancy most commonly to prevent or delay the onset of pre-eclampsia. Current NICE guidelines (4) recommend 75 to 150 mg/day from 12 weeks until birth for women with one major risk factor (HDP in previous pregnancy, chronic kidney disease, autoimmune disease, diabetes, chronic hypertension) or two moderate risk factors (primigravida, advanced maternal age, pregnancy interval of 10 years or more, overweight/obesity, family history of pre-eclampsia, multiple pregnancy). However, adherence to aspirin for preeclampsia prophylaxis among at risk women remains relatively low. A combination of factors has been found to influence adherence such as inadequate knowledge, lack of identification with the risk factors, beliefs about consequences of taking medication, pill burden in pregnancy and non-intention omission, communication and relationship with health care provider, and health-care environmental barriers (difficulties in obtaining medication and conflicting perceptions amongst healthcare providers regarding medication safety) (5-7). This is in spite of overwhelming evidence of safety in pregnancy.

Aspirin use is common in UK clinical practice, but it does not yet have a UK marketing authorisation to be sold as a pharmacy medicine for prevention of pre-eclampsia in pregnancy and for this indication must be prescribed (4). Although midwives cannot prescribe it, they play a crucial role for effectively counselling pregnant women, adopting reminder strategies for good adherence, and promoting effective communication and a positive relationship. Commencing before 16 weeks is associated with improved efficacy, and therefore midwives could help triage women to obtain aspirin through prompt referral. More recent trials have linked a nocturnal dose at 150 mg as being beneficial, and have suggested stopping at 36 weeks to avoid possible bleeding complications at birth (8). The benefit of taking aspirin in the last month of pregnancy is likely to be minimal. There are ongoing studies to see if targeting aspirin to women identified as high risk for later pre-eclampsia with blood tests (Placental growth factor-PLGF), maternal doppler measurements and blood pressure taken in the first trimester measurements is cost effective. If so, they may be introduced in the NHS as part of routine antenatal care.

Midwives’ knowledge and beliefs about their capabilities, their social and professional role and identity, and environmental context all influence how they engage in conversations about aspirin in pregnancy (9). Therefore, future accurate, easy-to-find information resources for both midwives and pregnant women are crucial for enabling clear and confident conversations regarding aspirin use during pregnancy.


1. Say L, Chou D, Gemmill A, et al. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health 2014;2:e323-33.

2. Magee LA, Brown MA, Hall DR, et al. The 2021 International Society for the Study of Hypertension in Pregnancy classification, diagnosis & management recommendations for international practice. Pregnancy Hypertens 2022;27:148-69.

3. Wu P, Green M, Myers JE. Hypertensive disorders of pregnancy. bmj. 2023 Jun 30;381.

4. National Institute for Health and Care Excellence. Hypertension in pregnancy: diagnosis and management. 2019.

5. Olson DN, Russell T, Ranzini AC. Assessment of adherence to aspirin for preeclampsia prophylaxis and reasons for nonadherence. American Journal of Obstetrics & Gynecology MFM. 2022 Sep 1;4(5):100663.

6. Shanmugalingam R, Mengesha Z, Notaras S, et al Factors that influence adherence to aspirin therapy in the prevention of preeclampsia amongst high-risk pregnant women: a mixed method analysis. PLoS One. 2020 Feb 27;15(2):e0229622.s

7. Vinogradov R, Smith VJ, Robson SC, Araujo-Soares V. Aspirin non-adherence in pregnant women at risk of preeclampsia (ANA): a qualitative study. Health Psychology and Behavioral Medicine. 2021 Jan 1;9(1):681-700.

8. Rolnik DL, Wright D, Poon LC, et al Aspirin versus placebo in pregnancies at high risk for preterm preeclampsia. New England Journal of Medicine. 2017 Aug 17;377(7):613-22.

9. Vinogradov R, Smith V, Hiu S, et al Let’s talk aspirin: A survey of barriers and facilitators faced by midwives when engaging in conversations about aspirin with women at risk of pre-eclampsia. Midwifery. 2023 Dec 1;127:103860.


January 2024

Dr Cristina Fernandez Turienzo, Midwife Senior Research Fellow

Prof Andrew H Shennan, Professor of Obstetrics, King’s College London