title: Normal Doppler flow velocity waveforms in the fetal ductus arteriosus in the first half of pregnancy.
abstract: Ductus arteriosus flow velocity patterns were studied in 298 women between 9 and 25 weeks of gestation using transvaginal or transabdominal Doppler ultrasound. Technically acceptable recordings were first obtained at 11 weeks resulting in 231 women for further analysis. Ductal waveforms show a significant change in shape from early pregnancy to mid-pregnancy, in that end-diastolic velocities are absent until 13 weeks, are present in 50% at 15 weeks and are present in all cases from 17 weeks. Regression analysis demonstrated a statistically significant linear increase with advancing gestational age for all flow velocity parameters except for the pulsatility index which remained stable during the entire study period.
authors.affiliation: Department of Obstetrics and Gynecology, Erasmus University, Rotterdam, The Netherlandsa.
authors.forename: C
authors.initials: C
authors.lastname: Brezinka
authors.forename: T W
authors.initials: TW
authors.lastname: Huisman
authors.forename: T
authors.initials: T
authors.lastname: Stijnen
authors.forename: J W
authors.initials: JW
authors.lastname: Wladimiroff