Low Dose Aspirin vs Placebo in Prevention of Recurrent Spontaneous Preterm Labour

Preterm birth-defined as delivery before 37 weeks of gestation-is a leading cause of neonatal morbidity and mortality worldwide, particularly in resource-limited settings. Women with a history of spontaneous preterm birth face a significantly higher risk of experiencing premature labor in subsequent pregnancies. Impaired uteroplacental blood flow, inflammation, and abnormal clot formation are key contributing factors to spontaneous preterm delivery.

Low-dose aspirin is an affordable, widely available medication that exerts anti-inflammatory and antithrombotic effects by inhibiting platelet aggregation and prostaglandin synthesis. This study aims to evaluate whether low-dose aspirin (75 mg daily), initiated between 8 and 16 weeks of gestation, can effectively reduce the incidence of recurrent spontaneous preterm labor in pregnant women with a prior history of premature delivery compared to a placebo. Participants will be monitored throughout their pregnancy up to 36 weeks or delivery to evaluate gestational age at birth and labor outcomes.

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Key information

Conditions

Preterm Labor Female Urogenital Diseases and Pregnancy Complications Obstetric Labor Complications Obstetric Labor, Premature Pregnancy Complications Premature Birth Urogenital Diseases

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age > 18 years.
Singleton alive pregnancy.
History of spontaneous preterm birth (22 to 37 weeks of gestation).
Hemoglobin (Hb) > 10 g/dL.
Absence of fetal anomalies on ultrasound examination.

Exclusion criteria

Primigravida.
Multiple pregnancy.
Maternal age > 40 years.
Known history of allergy or hypersensitivity to aspirin.
Known maternal comorbidities including Pregnancy-Induced Hypertension (PIH), Gestational Diabetes Mellitus (GDM), cardiac disease, HELLP syndrome, thrombocytopenia, thrombocytopathy, or epilepsy.
Presence of a cervical cerclage prior to study enrollment.

Treatment and study plan

Low-dose aspirin

Drug

Participants take low-dose aspirin 75 mg orally once daily starting from 8-16 weeks of gestation until 36 weeks of gestation or delivery (whichever comes first), alongside routine clinical care (progesterone and cervical cerclage if indicated).

Placebo

Other

Participants take a daily matching oral placebo tablet starting from 8-16 weeks of gestation until 36 weeks of gestation or delivery, alongside routine clinical care (per-rectal progesterone and cervical cerclage if indicated).

Primary outcomes

Incidence of Recurrent Spontaneous Preterm Labor

Time frame: From enrollment (8-16 weeks of gestation) up to delivery (up to 42 weeks of gestation)

Proportion of participants who experience spontaneous onset of labor and delivery prior to completing 37 weeks (259 days) of gestation.

Sponsors and collaborators

Lead sponsor

University of Health Sciences Lahore

Other

Registry information

Official study title

Comparison of Low Dose Aspirin vs Placebo in the Prevention of Recurrent Spontaneous Preterm Labou

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Aug 4, 2026
Registry last updated: Aug 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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