Maternal and Fetal Doppler Blood Flow Velocimetry Changes in the Management of Asymptomatic Preterm Labor With Vaginal Progesterone Tablet

Doppler sonography has been used for evaluation of different fetal responses to various drugs on doppler blood flow patterns in fetal circulation that may indicate poor fetal prognosis. To assess the uterine and fetal doppler blood flow velocimetry changes in the management of asymptomatic preterm labor with vaginal progesterone tablet, it is found that using a vaginal tablet of progesterone affects uterine, umbilical and fetal middle cerebral arteries in the second and third trimesters of pregnancy. This prospective Case series (uncontrolled longitudinal study) was conducted in an outpatient clinic and emergency unit in Moheb Yas hospital during 2015-2016. For all subjects, 200 mg vaginal progesterone tablet (one tablet before bedtime) was administered. Additionally, transvaginal Doppler sonography was performed to measure uterus, umbilical, and middle cerebral arteries before the treatment with progesterone and 24 hours after the treatment with that, respectively. The mean gestational age of participants was 28.8±2.9 weeks, ranging from 23 to 32 weeks of gestation. There was no significant change in the fetal middle cerebral artery-peak systolic velocity (MCA-PSV), middle cerebral artery resistance index (MCA-RI), MCA-PI, Umbilical arterial Systolic-Diastolic (UA S/D), Right UtA-RI and Left UtA-RI before the beginning of progesterone treatment to 24 hours after. The current study indicated that the 200 mg vaginal tablet of progesterone for treatment of preterm labor leads to a reduction in the middle cerebral artery and the uterine artery PI and RI and an increase in umbilical artery S/D, respectively. Vaginal progesterone can improve fetoplacental perfusion in pregnancies complicated by preterm labor. This a preliminary result from a case series study and it has to be confirmed by a randomized clinical trial in future.