Low dose acetylsalicylic acid in prevention of pregnancy-induced hypertension and intrauterine growth retardation in women with bilateral uterine artery notches

Objective To evaluate the efficacy of low-dose acetylsalicylic acid in the prevention of pregnancy-induced hypertension and intrauterine growth retardation in high-risk pregnancies as determined by transvaginal Doppler ultrasound study of the uterine arteries at 12 to 14 weeks of gestation. Design Randomised, double blind and placebo-controlled trial. Setting The Department of Obstetrics and Gynaecology, Tampere University Hospital, Finland. Population One hundred and twenty pregnant women considered to be at high risk of pre-eclampsia or intrauterine growth retardation were screened by transvaginal Doppler ultrasound at 12 to 14 weeks of gestation. Methods Ninety pregnant women with bilateral notches in the uterine arteries were randomised to receive acetylsalicyclic acid 0.5mg/kg/day (n = 45) or placebo (n = 45) from 12 to 14 weeks of gestation. Main outcome measures Hypertensive disorders of pregnancy and intrauterine growth retardation. Results Forty-three women on acetylsalicyclic acid and 43 on placebo were successfully followed up. The use of acetylsalicyclic acid was associated with a statistically significant reduction in the incidence of pregnancy-induced hypertension (11.6% vs 37.2%, RR = 0.31, 95% CI 0.13-0.78) and pre-eclampsia (4.7% vs 23.3%, RR = 0.2, 95% CI 0.05-0.86). The incidence of hypertension before 37 weeks of pregnancy was also significantly reduced (2.3% vs 20.9%, RR = 0.22, 95% CI 0.05-0.97). The reduction in the incidence of intrauterine growth retardation (2.3% vs 7%) was not statistically significant. Acetylsalicyclic acid was not associated with excess risk of maternal or fetal bleeding. Conclusion In women rated in Doppler velocimetry waveform analysis to be at high risk of pre-eclampsia, low-dose acetylsalicyclic acid reduces the incidence of pregnancy-induced hypertension and especially proteinuric pre-eclampsia.