Aspirin versus placebo in twin pregnancies for preeclampsia prevention: A multicentre, randomised, double-blind, placebo-controlled trial (ASPRE-T)

This is a double-blind randomised placebo-controlled multicentre trial. In the participating centres, all eligible women with dichorionic and monochorionic-diamniotic twin pregnancies 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 we will record maternal characteristics and medical history and perform an ultrasound scan to determine chorionicity, confirm gestational age from the measurement of the fetal crown-rump length of the bigger twin, diagnose any major fetal abnormalities, screen for chromosomal abnormalities based on the first-trimester combined test.

Women fulfilling the inclusion criteria will be invited to participate in the randomised trial of aspirin (150 mg/day) vs. placebo from 11 to 14 until 36 weeks’ gestation. The aim of the trial 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 preeclampsia with delivery <37 weeks’ gestation.

The trial is powered for a 50% reduction in incidence of preterm preeclampsia from an anticipated 5.5% in the placebo group to 2.75% in the aspirin group. For a power of 90%, using a two sided test at the 5% level of significance, it is necessary to randomise 2,400 pregnancies.

Effects of dietary nitrate supplementation on pregnancies complicated by chronic and new onset hypertension - The BEET-BP Trial

This is a double-blind placebo controlled multicentre randomised trial. All participants with new onset hypertension (gestational hypertension or preeclampsia or chronic hypertension) presenting between 24 to 36 weeks’ gestation fulfilling the eligibility criteria will be offered recruitment into the trial. Participants will be randomly allocated to either 70 mL beetroot juice concentrate or 70 mL nitrate deplete beetroot juice placebo on a 1:1 basis. This juice will be taken at the same time each morning until delivery.

The primary outcome of this trial is to determine the effect of beetroot juice on gestational age of delivery secondary to preeclampsia. The sample size is calculated with the aim to prove a 10 day delay in gestation of delivery with preeclampsia in the beetroot juice concentrate arm versus the nitrate deplete beetroot juice arm. Assuming the study population will be comprised of 75% gestational hypertension and 25% chronic hypertension with rates of superimposed preeclampsia of 40% in the gestational hypertension group and 30% in the chronic hypertension group. 320 women (160 in each arm) will need to be randomised for a power of 90%. Assuming 80% acceptance to randomisation, 400 patients will need to be screened.