Aspirin (ASA) Therapy and Preeclampsia Prevention

November 11, 2020 updated by: University of Tennessee

A Pragmatic Randomized Study Comparing 81 mg Aspirin Versus 162 mg Aspirin in the Prevention of Preeclampsia During Pregnancy

According to U.S. Pharmacist® "low-dose aspirin refers to dosages between 81 mg and 325 mg taken every day to prevent heart attacks, strokes, and colon cancer." It has been found through research that low-dose aspirin also decreases the risk of preeclampsia. The American College of Obstetrics and Gynecologists (ACOG) recommends low-dose aspirin (81mg/day) for women at high risk of preeclampsia. However, some researchers report that a dose of aspirin < 100 mg/day does not seem to decrease the risk of preeclampsia. Another trial studying patients who are at a high risk for preterm preeclampsia, reported a reduction in the occurrence of preeclampsia among patients taking aspirin at a dose of 150 mg.

The purpose of this pragmatic randomized study is to compare the difference in the effectiveness of two doses of aspirin: 81 mg versus 162 mg in the prevention of preeclampsia in pregnant women who are at a moderate to high risk for developing preeclampsia.

Study Overview

Detailed Description

Rationale - The risk factors associated with preeclampsia (early-onset and late-onset, singleton deliveries) include the following maternal characteristics and clinical factors (Washington State, 2003-2008; ACOG 2018): age < 20 years, age >34 years, African-American race, marital status-single, first pregnancy, diabetes mellitus, chronic hypertension, infertility treatment, infant sex male, and congenital anomalies.

Low dose aspirin decreases the risk of preeclampsia. The 2018 ACOG Committee Opinion on "Low-dose aspirin use during pregnancy" recommends the use of 81mg/day of aspirin for patients with risk factors for preeclampsia. However, it has been reported that a dose of aspirin < 100 mg/day does not seem to decrease the risk of preeclampsia.

Rolnick et al., studying patients at high risk for preterm preeclampsia, reported a 63% relative risk reduction among patients taking aspirin at 150mg per day versus placebo. We anticipate a more conservative rate of 40% relative risk reduction, from 35% to 21%, for patients taking 162mg per day.

Study/Project Population - We will include pregnant women up to 28.0 weeks gestation coming to the Regional One Health Obstetric (OB) Clinic for prenatal care, who meet ACOG's definition of high or moderate risk of developing preeclampsia during their current pregnancy (Low risk subjects will not be included).

Those risk factors are:

High Rish [ACOG recommends low-dose aspirin if the patient has one or more of these high-risk factors.]

  1. History of preeclampsia, especially when accompanied by an adverse outcome
  2. Multifetal gestation
  3. Chronic hypertension
  4. Type 1 or 2 Diabetes mellitus
  5. Renal disease [>300 mg/24-hour urine; protein creatinine ratio > 0.3; 1+ proteinuria; creatinine >1.2]
  6. Autoimmune disease (for example, systemic lupus erythematosus, antiphospholipid syndrome)

    Moderate Risk [ACOG recommends consideration of low-dose aspirin if the patient has more than one of these moderate-risk factors. Moderate-risk factors vary in their association with increased risk of preeclampsia.]

  7. Nulliparity
  8. Obesity (body mass index greater than 30)
  9. Family history of preeclampsia (mother or sister)
  10. Sociodemographic characteristics (African American race, low socioeconomic status)
  11. Age 35 years or older
  12. Personal history factors (e.g., low birthweight or small for gestational age, previous adverse pregnancy outcome, more than 10-year pregnancy interval)

    Low Risk [ACOG does not recommend low-dose aspirin.]

  13. Previous uncomplicated full-term delivery

Research Design - This is a prospective clinical trial with binomial outcome and random assignment to two independent study groups, with a 1:1 ratio of assignment to 162mg versus 81mg of aspirin recommended daily.

For our sample size calculation, we use a one-sided Likelihood Ratio Chi-square Test for two proportions, with a Type I error rate of 5%, and power of 80%. To detect a 40% relative risk reduction in term preeclampsia prevalence, from 15% to 9%, requires a total (N)umber of 720 patients. We estimate a 20% attrition due to causes including non-compliance, delivering at other hospitals, and non-hospital deliver; and therefore, plan to recruit 900 patients (450 patients per group).

To compare the ratios of preeclampsia incidence between two assigned groups, assigned to 162mg or 81mg of daily aspirin, we plan to use a Likelihood Ratio Chi-square Test or Fisher's exact test.

We anticipate a 12-month recruitment period for this study. The number of deliveries at Regional One Health (ROH) for the years 2017 and 2018 were 3325 and 3031 respectively. However, for this same period, the number of patients receiving prenatal care through Regional One Health Outpatient Center (MedPlex) were 1564 and 1651 respectively. This reveals that approximately 50% of those patients delivering at ROH did not receive prenatal care through Regional One Health.

Study/Project Procedures - We will screen for eligibility by reviewing the clinic appointment lists, matching patient's reason for visit with key words indicating they are likely candidates. Subjects meeting inclusion criteria will be further screened for eligibility during their OB clinic visit. The willing subjects will have the informed consent presented, thoroughly explained, and given an opportunity to ask questions.

Consented subjects will be randomly assigned and prescribed a daily dosage of 81 mg or 162 mg of aspirin to be taken each evening at bedtime. (See additional description below). Study drug bottles will be dispensed on the day of enrollment. Subjects will be instructed to continue taking the aspirin according to their randomization through the end of their pregnancy.

Subjects will be randomized in consecutive order, entering their basic information (name, date of birth, medical record number, date/time of randomization, randomization number) on a master log.

Patients recruited in the study will undergo a standard treatment ultrasound during the first trimester. At the time of consent, study subjects will be asked about their willingness to have a maternal uterine artery doppler ultrasound performed specifically for research. The maternal uterine artery doppler ultrasound will require an additional 3 minutes of the subject's time. If the subject agrees to participate in this portion of the study, they will initial the affirmative response line of the consent form.

The additional information collected during the maternal uterine artery doppler ultrasound will add to the body of knowledge used as predictors of preeclampsia. This information will not be used for clinical management.

We will collect data from the patient's electronic medical record (EMR) and the patient's fetus'/newborn's EMR, established at Regional One Health (clinic and hospital). This will include information pertaining to health history, current medical treatment, medications, pregnancy ultrasound scans, labor, delivery, and birth information.

Collected paper records will be maintained in the research office under locked conditions. Electronic data will be retrieved, entered and stored in a study titled REDCap Data File, utilizing password protection for access. We will request the guidance and assistance of the Center for Biomedical Informatics (CBMI) personnel as is needed.

Outcome Measures - Our primary outcome will be the occurrence of preeclampsia. Preeclampsia will be defined according to the 2018 American College of Obstetricians and Gynecologists recommendations.

Interim analysis will be conducted after 318 enrolled subjects have delivered, evaluating the outcomes of: 'no preeclampsia,' 'preterm preeclampsia,' and 'term preeclampsia.' Enrollment will continue if the results of the first interim analysis are inconclusive. At that time, continuation of enrollment to 646 subjects delivered with a second interim analysis, or up to enrollment of 900 subjects delivered for a third, final analysis.

Study Type

Interventional

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Tennessee
      • Memphis, Tennessee, United States, 38103
        • Regional One Health, Obstetrics Outpatient Clinic

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years to 50 years (Child, Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Pregnant females ages 14 to 50 years old
  • Up to 28.0 weeks gestation (may initially base on last menstrual period (LMP), but confirmed with ultrasound (US)
  • Be at high risk or moderate risk for developing preeclampsia as defined by the American College of Obstetrics and Gynecologists (ACOG-2018), the Society for Maternal-Fetal Medicine (SMFM-2018), and the United States Preventive Services Task Force (USPSTF-2017)

Exclusion Criteria:

  • Less than 14 years old or greater than 50 years old
  • Allergy or contraindication to taking aspirin (i.e. nasal polyps, asthma with aspirin-induced bronchoconstriction)
  • History of gastrointestinal bleeding
  • Active peptic ulcer disease
  • Other sources of active Gastrointestinal/Genitourinary bleeding
  • Physician or provider refusal
  • Patient refusal
  • History of bleeding or clotting disorder (i.e. Factor V, von Willebrand, hemophilia)
  • Severe renal failure (Glomerular Filtration Rate < 10 ml/min)
  • Taking aspirin prior to pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Group 1 - ACOG recommended dose
oral dose: 81 mg aspirin daily; designated by odd number assignment [1-001, 1-003, 1-005, etc. to 899]
take one (1) 81 mg tablet each evening
Other Names:
  • Group 1 - ACOG recommended dose
Active Comparator: Group 2 - Comparison Dose
oral dose: 162 mg aspirin daily; designated by even number assignment [2-002, 2-004, 2-006, etc. to 900]
take two (2) 81 mg tablets each evening
Other Names:
  • Group 2 - Comparison Dose

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Preeclampsia
Time Frame: approximately 30 weeks; from 12 weeks gestation until the day of delivery
Occurrence of preeclampsia: categorized as - none, preterm, or term
approximately 30 weeks; from 12 weeks gestation until the day of delivery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Giancarlo Mari, MD, FACOG, OB/ GYN Department Professor and Chair

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

June 1, 2020

Primary Completion (Anticipated)

November 30, 2021

Study Completion (Anticipated)

November 30, 2021

Study Registration Dates

First Submitted

October 18, 2019

First Submitted That Met QC Criteria

November 7, 2019

First Posted (Actual)

November 12, 2019

Study Record Updates

Last Update Posted (Actual)

November 13, 2020

Last Update Submitted That Met QC Criteria

November 11, 2020

Last Verified

November 1, 2020

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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