This trial has been completed.

Conditions small for gestational age, infant, very low birth weight, fetal growth retardation, preeclampsia, premature birth
Treatments acetylsalicylic acid, placebo
Phase phase 2
Sponsor Centre Hospitalier Universitaire de Québec, CHU de Québec
Start date November 2014
End date October 2016
Trial size 50 participants
Trial identifier NCT02280031, 2014-1817


Low-dose aspirin started in the first-trimester has been associated with a decrease of preeclampsia, fetal growth restriction and preterm birth in high-risk pregnancies. Multiple pregnancies are considered a risk factor for all those adverse outcomes. The main objective of the current trial is to evaluate whether a dose of 80 mg of aspirin is associated with an improvement of birthweight compared to placebo in twin pregnancies.

United States No locations recruiting
Other countries No locations recruiting

Study Design

Allocation randomized
Endpoint classification safety/efficacy study
Intervention model parallel assignment
Masking double blind (subject, caregiver, investigator, outcomes assessor)
Primary purpose prevention
(Active Comparator)
Acetylsalicylic Acid 80mg administered daily at bedtime
acetylsalicylic acid Aspirin
Capsule containing Acetylsalicylic Acid 80mg pill with lactose
(Placebo Comparator)
Identical placebo administered daily at bedtime
placebo Control
Capsule containing placebo pill with lactose

Primary Outcomes

Birth weight
time frame: At delivery

Secondary Outcomes

Low birth weight (birthweight below 2,500 grams)
time frame: At delivery
Very low birth weight (birthweight below 1,500 grams)
time frame: At birth
Fetal growth restriction (birthweight below the 10th or 3rd percentile for gestational age)
time frame: 16-18 and 22-24 weeks
Preterm birth (delivery before 37 weeks)
time frame: At delivery
Very preterm birth (delivery before 34 weeks)
time frame: At delivery
Preeclampsia (according to American College of Obstetricians and Gynecologists 2014 guidelines definition)
time frame: At delivery
Early-onset preeclampsia (before 34 weeks)
time frame: At delivery
Mean uterine artery pulsatility index
time frame: 22-24 weeks
Aspirin resistance (PFA-100 below 150)
time frame: 16-18 and 22-24 weeks
Cervical length
time frame: 22-24 weeks

Eligibility Criteria

Female participants at least 18 years old.

Inclusion Criteria: - Gestational age between 8 0/7 and 13 6/7 weeks - Twin pregnancy confirmed by ultrasound Exclusion Criteria: - One or two negative heart beat - Previous hypertensive disorder of pregnancy - Pre-existing hypertension or diastolic blood pressure >90 mmHg at randomization - Pre-existing nephropathy - Pre-existing diabetes (type 1 or 2) - Anaphylactic allergy to lactose - Known coagulopathy (antithrombin III deficiency, factor V Leiden, antiphospholipid syndrome, the prothrombin mutation, deficiency of protein S or protein C) - Use of heparin or other anticoagulants. - Contre-indications to aspirin - Discordance of crown-rump length greater than 20%. - Fetal anomalies (cystic hygroma, nuchal translucency > 95th percentile, anencephaly, omphalocele, etc.) - Previous or current gastric ulcer

Additional Information

Official title Effect of Low Dose Aspirin on Birthweight in Twins: The GAP Trial
Principal investigator Emmanuel Bujold, MD,MSc,FRCSC
Description Twin pregnancies represent approximately 3% of births and are associated with increased risks of complications such as preeclampsia, fetal growth restriction and preterm birth. All of these complications are commonly associated impaired placental function and low birth weight. Most prophylactic measures tested over the years have failed to prevent these adverse outcomes in twin pregnancies. Since administration of low-dose of aspirin can improve placental function and all these adverse outcomes in high-risk pregnancies, mainly in women with prior adverse outcomes, we suggest that similar benefits could be seen in twins. We are expecting that the administration of low-dose of aspirin starting in the first-trimester in twin pregnancies could lead to an improvement of placental function, a reduction or these adverse perinatal outcomes and therefore to an improvement of birthweight.
Trial information was received from ClinicalTrials.gov and was last updated in December 2016.
Information provided to ClinicalTrials.gov by Centre Hospitalier Universitaire de Québec, CHU de Québec.