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% Cl 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.