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Study of Acetylsalicylic Acid (Aspirin) 150 mg for Prevention of Complications in Pregnant Women with Chronic Hypertension

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on pregnant women with chronic hypertension, a condition where blood pressure remains consistently high. The research examines how acetylsalicylic acid (also known as aspirin) affects pregnancy-related complications including pre-eclampsia (a serious condition causing high blood pressure during pregnancy), fetal growth restriction (when a baby doesn't grow properly in the womb), and other pregnancy-related blood pressure problems.

The study compares the effects of taking 150 mg of acetylsalicylic acid daily with a placebo to prevent serious complications that could affect both mother and baby. These complications include pre-eclampsia, separation of the placenta from the womb, reduced baby growth, early delivery, and other serious health issues for both mother and baby.

Participants in this study will receive either acetylsalicylic acid in the form of gastro-resistant tablets (tablets that dissolve in the intestine rather than the stomach) or identical-looking placebo tablets. The treatment continues for 6 months during pregnancy. The study is designed so that neither the pregnant women nor their healthcare providers know which treatment they are receiving during the study period.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial participation phase

    You will begin participation between 10 weeks and 19 weeks + 6 days of pregnancy

    Your pregnancy must be confirmed as a single baby pregnancy (not twins or multiple)

    You must have chronic high blood pressure (treated or untreated)

  2. Step 2

    Medication administration

    You will receive either acetylsalicylic acid (150 mg tablets) or a placebo tablet

    The medication is to be taken daily by mouth

    The tablets are specially coated to protect your stomach (gastro-resistant)

    You will need to maintain a diary to record your medication intake

  3. Step 3

    Monitoring during pregnancy

    Your pregnancy will be monitored for various conditions including:

    - High blood pressure complications in pregnancy

    - Baby's growth progress

    - Any signs of the placenta separating from the uterus

    Blood and urine samples will be collected to measure specific proteins related to pregnancy

  4. Step 4

    Birth and immediate follow-up

    Your delivery will be monitored and documented

    Information about your baby's birth weight and overall health will be recorded

    Any complications during delivery will be documented

  5. Step 5

    Long-term follow-up

    Your child's development will be monitored at age 2 and 4 years

    The study will continue until November 2026

Who can join the trial?

5 criteria

  • Must be a pregnant woman between 10 weeks and 19 weeks plus 6 days of pregnancy
  • Must have chronic high blood pressure (whether currently being treated or not)
  • Must be carrying only one baby (singleton pregnancy)
  • Must be willing and able to provide written informed consent to participate in the study
  • Must have active social security coverage

Who cannot join the trial?

14 criteria

  • Known allergy or hypersensitivity to aspirin or other similar medications
  • Multiple pregnancy (carrying more than one baby)
  • History of bleeding disorders or significant bleeding problems
  • Active peptic ulcer disease (stomach or intestinal ulcers)
  • Current use of blood-thinning medications (such as warfarin)
  • Liver disease with abnormal blood clotting
  • History of severe kidney disease
  • Previous adverse reaction to aspirin therapy
  • Participation in another clinical trial within the past 30 days
  • Any condition that, in the investigator's opinion, makes the patient unsuitable for the study
  • Inability to provide informed consent
  • Planned delivery at a non-participating hospital
  • Current regular use of aspirin or NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)
  • Platelet count less than 100,000 per microliter of blood (a condition affecting blood clotting)
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Investigated drugs

Aspirin (acetylsalicylic acid) is a medication commonly used to reduce pain, fever, and inflammation. In this trial, it is being studied for its potential benefits in pregnant women with chronic high blood pressure. The medication works by preventing the formation of certain substances in the body that cause inflammation and blood clotting. When used during pregnancy, it may help prevent serious complications by improving blood flow to the placenta and reducing the risk of blood clots.

What is already known about the treatment

Acetylsalicylic acid (Aspirin) - A widely used medication administered orally in tablet form that belongs to the class of nonsteroidal anti-inflammatory drugs (NSAIDs). In pregnancy-related clinical trials, it is specifically studied at a dose of 150 mg daily for preventing complications in women with chronic hypertension, particularly focusing on reducing the risk of pre-eclampsia and fetal growth restriction. The medication works by inhibiting platelet aggregation and prostaglandin synthesis, which helps improve placental blood flow and reduce inflammation, potentially leading to better maternal and fetal outcomes during pregnancy. This well-established drug has extensive medical literature supporting its safety profile and is widely recognized in obstetric medicine for its preventive properties in high-risk pregnancies.

Investigated diseases

  • Chronic Hypertension in Pregnancy

    A condition where high blood pressure exists before pregnancy or develops before 20 weeks of gestation. The elevated blood pressure continues throughout pregnancy, putting additional stress on the cardiovascular system.

  • Pre-eclampsia

    A pregnancy complication characterized by high blood pressure and signs of damage to organ systems, typically occurring after 20 weeks of pregnancy. It involves reduced blood flow to the placenta and can cause swelling, protein in urine, and other symptoms.

  • Fetal Growth Restriction

    A condition where an unborn baby is smaller than expected for its gestational age due to not growing at a normal rate inside the womb. The baby's estimated weight is below what's expected for its gestational age, often falling below the 10th percentile.

  • Placental Abruption

    A serious condition that occurs when the placenta partially or completely separates from the inner wall of the uterus before delivery. This separation can reduce or block the baby's supply of oxygen and nutrients.

  • Preterm Delivery

    The birth of a baby before 37 weeks of pregnancy have been completed. The earlier the delivery occurs in pregnancy, the more challenging it can be for the baby.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516461-36-00Protocol codeCHASAPEstimated enrolment500 patientsSponsorCentre Hospitalier Intercommunal Creteil

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