Aims
To determine the efficacy and safety of aspirin therapy in high risk women with pre-existing type 1 or type 2 diabetes in preventing pre-eclampsia.
Methods
A retrospective cohort study of 164 pregnancies with pre-existing diabetes delivering between January 2013 and February 2019 was performed. Women who were deemed high risk by their treating clinician were prescribed aspirin prior to 16 weeks and were considered case subjects (n = 45). The primary outcome was pre-eclampsia, and secondary outcomes were other measures of placental insufficiency. Post-partum haemorrhage (PPH) was the primary measure of complications of aspirin therapy.
Results
At baseline, the aspirin treated cohort had a higher median HbA1c (7.0 vs. 6.4, P = 0.012), more nephropathy (OR 2.6 [1.1-6.0], P = 0.021) and more anticoagulant use (OR 9.0 [1.7-46.4], P = 0.006) than controls, consistent with their higher risk. There was no difference in the incidence of pre-eclampsia (OR 0.9 [0.3-2.8], P = 0.838) or any other measure of placental insufficiency (OR 1.6 [0.6-4.0], P = 0.336) after adjusting for baseline differences. However, aspirin therapy was associated with an increased risk of PPH (OR 2.7 [1.0-7.2], P = 0.038), which was independent of the combined effects of maternal body mass index (BMI), anticoagulant therapy, induction of labour, mode of delivery and birthweight (OR 3.6 [1.2-11.0], P = 0.021). The aspirin treated group had less induction of labour (OR 0.3 [0.2-0.7], P = 0.002) but more intervention in delivery (OR 2.2 [1.0-4.8], P = 0.038) than the control group.
Conclusions
Women who received aspirin in this study had a higher risk profile for pre-eclampsia than the control group but similar incidence of pre-eclampsia, suggesting aspirin had a protective effect. However, any reduction in pre-eclampsia in these high risk women was accompanied by significantly increased risks of PPH and intervention in delivery. Further large randomised controlled trials are needed to justify the use of aspirin in this cohort.