ASPRE-T is a double-blind randomised placebo-controlled trial. The trial will be conducted in compliance with the protocol, the Declaration of Helsinki (1996), the principles of Good Clinical Practice (GCP) and applicable regulatory requirements.

This is a multicentre trial. In the participating centres, all eligible women with DCDA or MCDA twin pregnancy attending for their routine first hospital visit in pregnancy at 11-13 weeks’ gestation will be invited to participate in the trial. In this visit maternal characteristics and medical history will be recorded and an ultrasound scan to determine chorionicity (Sepulveda et al., 1996)will be performed, gestational age from the measurement of the fetal crown- rump length (CRL) (Robinson and Fleming, 1975) of the bigger twin will be confirmed, any major fetal abnormalities (Syngelaki et al., 2011) will be diagnosed, chromosomal abnormalities based on the first-trimester combined test (Snijders et el., 1998, Kagan et al., 2008) will be screened. The Principal Investigators for each site are fetal medicine experts who follow the Fetal Medicine Foundation (FMF) guidelines on how to undertake the appropriate measurements

The objective of the study is to examine if the prophylactic use of low-dose aspirin from the first-trimester of pregnancy in women with twin pregnancy can reduce the incidence of PE with delivery

The primary objective is to determine the effect of low-dose aspirin on the incidence of PE with delivery.