The Effect of Two Aspirin Dosing Strategies for Obese Women at High Risk for Preeclampsia

Study Overview
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Brief Summary
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Low dose aspirin (LDA) is used for preeclampsia (PE) prevention in high risk women, but the precise mechanism and optimal dose is not known. Evidence in the non-obstetric literature suggests AR may be more common among patients with a high body mass index (BMI). Recent unpublished data showed that LDA substantially lowers TxB2 levels regardless of BMI, but rates of complete platelet inhibition are lower in women with BMI ≥40. This data suggests that higher doses of ASA may be necessary in obese women. Therefore we plan determine if use of 162mg compared to the traditional 81mg ASA decreased rates of preeclampsia in women considered high risk for developing preclampsia.

Detailed Description
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Evidence suggests that an imbalance in prostacyclin and thromboxane A2 (TxA2) plays a key role in PE. Aspirin (ASA) has a dose-dependent effect blocking production of TxA2, a potent stimulator of platelet aggregation (PA) and promoter of vasoconstriction. Incomplete inhibition of PA, designated aspirin resistance (AR), can be reduced by increasing the ASA dose.

Official Title
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The Effect of 81mg vs 162mg ASA for Preeclampsia Prevention in Obese Women at High Risk for Developing Preeclampsia

Conditions
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Preeclampsia

Intervention / Treatment
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* Drug: 162mg aspirin dose


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI at enrollment >/= 30 plan for ASA for preeclampsia prevention Exclusion Criteria: BMI < 30 already on ASA

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: 81 mg daily aspirin dose<br>obese women >30 BMI at risk for preeclampsia will receive recommended 81mg ASA | |
| Active Comparator: 162mg daily aspirin dose<br>obese women >30 BMI at risk for preeclampsia will receive increased dose of 162mg ASA | Drug: 162mg aspirin dose<br>* 2 pills of 81mg aspirin<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Diagnosis of preeclampsia | by acog definitions | Through study completion, an average for 10 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of aspirin resistance based on incomplete inhibition of TBx2 | incomplete platelet inhibition measured by urinary TBx2 | Through study completion, an average for 10 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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aspirin, obesity