Usefulness of aspirin therapy in high-risk pregnant women with abnormal uterine artery Doppler ultrasound at 14-16 weeks pregnancy: randomized controlled clinical trial.

AIM: To assess the effectiveness of low-dose aspirin in the prevention of preeclampsia and intrauterine growth restriction (IUGR) in high-risk pregnant women with abnormal findings at uterine artery Doppler velocimetry performed at 14-16 weeks.

DESIGN: Randomized controlled clinical trial.

SETTING: Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Egypt.

METHODS: The trial enrolled 139 women at risk of preeclampsia or IUGR, with abnormal uterine artery Doppler findings that included the presence of unilateral or bilateral diastolic notch, high resistance index (RI), or high pulsatility index (PI) at 14-16 weeks of gestation. The women were randomly allocated into two groups, one receiving aspirin since admission to hospital (n=74) and the other serving as control (n=65). All women were followed up until delivery to assess maternal and perinatal outcomes. T-test was used for comparison of quantitative variables, and categorical variables were compared by chi2 test. OUTCOME CRITERIA: Development of mild or severe preeclampsia, time of onset of preeclampsia, preterm delivery, and the development of IUGR.

RESULTS: Preeclampsia developed in 35% of women receiving aspirin and 62% of women in the control group (P=0.003), with severe preeclampsia developing in 8% and 23% of women (P=0.215), respectively. Preeclampsia before 37 weeks of gestation was recorded in only 4% of women receiving aspirin as opposed to 83% of controls (P<0.001). In the group of women receiving aspirin, 19% of newborns suffered from IUGR as opposed to 32%of newborns in the control group (P=0.106). There was no significant difference between the two groups in the rate of preterm delivery (P=0.080), mode of delivery (P=0.971), Apgar score <5 after one minute (P=0.273) and after 5 minutes (P=0.941), maternal or neonatal bleeding (P=0.948), and neonatal birth weight (P=0.399).

CONCLUSION: Low-dose aspirin administered as early as 14-16 weeks of gestation to pregnant women at high risk of preeclampsia with abnormal uterine Doppler findings may reduce or modify the course of severe preeclampsia. Its effects on the prevention of IUGR need further evaluation.