Comparing the Efficacy of 75mg Versus 150mg Aspirin for the Prevention of Preeclampsia in High-Risk Pregnant Women

Pre-eclampsia is a major factor in both maternal and fetal morbidity and mortality. The most widely investigated preeclampsia prevention medication is low dose Aspirin. However, guidelines differ considerably regarding the prophylactic dose of Aspirin for preeclampsia. Pre-eclampsia (PE) affects 5-7% of all pregnancies and along with eclampsia is the major contributor to maternal morbidity and 10-15% of maternal mortality and also perinatal mortality. Low dose aspirin administration can reduce vasoconstriction and decreases thrombosis of the vessels related to placenta, thereby increases blood flow and protects against to pregnancy related complication like preeclampsia, IUGR or FGR. One of the major therapeutic interventions to prevent preeclampsia is the use of Aspirin (a COX-II inhibitor with anti-inflammatory and anti-thrombotic properties). Initiating low-dose aspirin (LDA) therapy in early pregnancy from 12 weeks can prevent the onset of pre-eclampsia or delay it. The antiplatelet and vasodilatory effect of aspirin induced by the inhibition of cyclooxygenase-1 (COX-1) and reduced production of thromboxane, a potent vasoconstrictor and platelet aggregator, enhances placental blood circulation. Moreover, potential anti-inflammatory properties can improve endothelial dysfunction and oxidative stress, which are the central pieces of preeclampsia mechanisms.

The dose of aspirin used in most hospital settings is low dose, which has its benefits outweigh the risks and side effects of the drug. Many studies evaluated low doses of Aspirin 60-80mg showing a 10%-50% reduction in the incidence of preeclampsia, while a few studies also evaluated the efficacy of a 150mg dose. To our knowledge, this is among very few studies to investigate the effectiveness of relatively higher doses of aspirin in the Pakistani population.

Inclusion criteria

• Screen positive women
• Age 18 - 30 y
• Gestational Age 11 - 13+6 weeks
• Singleton Pregnancy
• Estimated risk for preterm PE of > 1 in 100 (Reference - Fetal Medicine Foundation)

Exclusion criteria

• Screen negative women
• Age > 30 y
• Gestational Age > 14 weeks
• Multiple Gestation
• Estimated risk for preterm PE of < 1 in 100 (Reference - Fetal Medicine Foundation)