Information
Low dose aspirin has been shown to reduce the risk of pre-eclampsia, fetal growth restriction (FGR) and spontaneous preterm labour in at risk pregnancies.
Pre-eclampsia affects approximately 1% of pregnancies and increases the risk of maternal and perinatal mortality and morbidity. FGR affects up to 10% of pregnancies and is associated with serious adverse outcomes including stillbirth. Preterm delivery affects up to 8% of pregnancies and is also associated with perinatal morbidity and mortality. Some preterm birth is related to poor placentation which is the same issue that arises with pre-eclampsia and FGR.
Aspirin is a non steroidal anti-inflammatory drug with antiplatelet properties. It is a cyclooxygenase inhibitor of COX1 and 2 and interferes with prostaglandin synthesis promoting vasodilatation and reducing platelet aggregation.
Women should be risk assessed by their community midwife at the booking visit (8-11 weeks), referred to/discussed with the locality obstetric consultant and have aspirin started by 12 weeks gestation if possible (at the latest 20 weeks).
- One high risk factor: Prescribe 150mg aspirin nocte from 12 weeks until delivery, or as soon as a risk factor is identified
- Hypertensive disease during a previous pregnancy
- Chronic kidney disease
- Chronic hypertension
- Autoimmune disease such as SLE or antiphospholipid syndrome
- Type 1 or type 2 diabetes
- At risk of preterm birth:
- previous mid-trimester loss
- spontaneous preterm delivery <34 weeks
- spontaneous rupture of the membranes <34 weeks
- PAPPA <0.4 MOM (this is measured as part of the combined first trimester screening for trisomies 21, 18 and 13, results available around 14-15 weeks gestation)
- 2+ moderate risk factors: Prescribe 150mg aspirin nocte from 12 weeks until delivery, or as soon as a risk factor is identified
- First pregnancy
- Age 40 years or older
- Pregnancy interval of more than 10 years
- Body mass index (BMI) of 35 kg/m2 or more at first visit
- Family history of pre-eclampsia
- Multi-fetal pregnancy
Ensure that women at increased risk are appropriately offered and prescribed low dose aspirin antenatally to reduce the risk of pre-eclampsia, IUGR and preterm birth.
NB. Side effects of aspirin include: GI irritation, tinnitus, bronchospasm, hypersensitivity, severe cutaneous adverse reactions.
Contraindications:
- A history of true hypersensitivity to aspirin, salicylates or another nonsteroidal anti-inflammatory drug (NSAID).(Symptoms of hypersensitivity to aspirin or salicylates include bronchospasm, urticaria, angioedema, and rhinitis. These can occur in isolation or in combination and can lead to severe or life-threatening reactions)
- Active pathological bleeding, such as peptic ulcer or intracranial haemorrhage
- Severe cardiac failure
- Severe hepatic impairment
- Severe renal impairment
- Haemophilia or another haemorrhagic disorder (including thrombocytopenia)
NICE Hypertension in Pregnancy June 2019 https://www.nice.org.uk/guidance/ng133
The impact of low-dose aspirin on adverse perinatal outcomes: a meta-analysis and meta-regression analysis.
Ultrasound Obstet Gynecol Sep 19 Turner et al.
Ayala DE, Ucieda R, Hermida RC. Chronotherapy with low-dose aspirin for prevention of complications in pregnancy. Chronobiol Int 2013;30:260-79.
Caron N, Rivard GE, Michon N, et al. Low-dose ASA response using the PFA- 100 in women with high-risk pregnancy. J Obstet Gynaecol Can 2009;31:1022-7.
Am J Obstet Gynaecol 2018 Oct;219(4):399.e1-399.e6. doi: 10.1016/j.ajog.2018.06.011. Epub 2018 Jun 18 Andikopolou et al
