Uteroplacental circulation in early pregnancy complicated by threatened abortion supplemented with vaginal micronized progesterone or oral dydrogesterone

ObjectiveTo compare the influence of vaginal micronized progesterone and oral dydrogesterone supplementation on uteroplacental circulation in early pregnancy that is complicated by threatened abortion.DesignRandomized, parallel group, double-blind, double dummy–controlled study.SettingTertiary care university hospital.Patient(s)Fifty-three patients with threatened abortion and a living embryo.Intervention(s)Three hundred milligrams of micronized vaginal progesterone or 30 mg of oral dydrogesterone daily supplementation for 6 weeks, serial transvaginal Doppler ultrasound measurement of pulsatility index, resistance index, and systolic/diastolic ratio of the spiral arteries, the uterine arteries, and the intrachorionic area.Main Outcome Measure(s)Uteroplacental blood flow.Result(s)The study demonstrated that vaginal progesterone administration, but not oral dydrogesterone treatment, results in the decrease in the spiral artery pulsatility and resistance index and systolic/diastolic ratio. Insignificant decrease in pulsatility index and resistance index of the uterine artery was observed at >9 weeks and was not associated with treatment regimen. Dydrogesterone treatment was only accompanied by the decrease in the uterine artery systolic/diastolic ratio.Conclusion(s)Vaginal progesterone and oral dydrogesterone supplementation have a different influence on the uteroplacental circulation in early pregnancy that is complicated by threatened abortion.