Resolution of high uterine artery pulsatility index and notching following sildenafil citrate treatment in a growth-restricted pregnancy
Journal
Ultrasound in Obstetrics and Gynecology
Journal Volume
40
Journal Issue
5
Pages
609-610
Date Issued
2012
Author(s)
Abstract
Fetal growth restriction (FGR) and pre-eclampsia remain the major causes of neonatal and maternal morbidity and mortality1. These two conditions have been shown to result from abnormal trophoblast invasion, which compromises uteroplacental circulation2. Uterine artery Doppler ultrasonography and a variety of proteins and hormones have been studied as potential early biomarkers of FGR or pre-eclampsia3. However, after identifying high-risk patients, management strategies are limited to increasing frequency of surveillance. Recent studies have demonstrated that sildenafil citrate significantly enhances vasodilation of myometrial small arteries and is also associated with fetal weight gain4-6, which offers a potential therapeutic possibility for FGR. We report here a case demonstrating improvement of uterine artery Doppler ultrasonography following sildenafil citrate treatment in a 26-week pregnancy with FGR. A 30-year-old healthy woman, gravida 3 para 0, presented at our hospital at 26 weeks' gestation with FGR. Repeat ultrasound examination revealed the estimated fetal weight to be 460 g (< 5th percentile). Absent end-diastolic velocity in the umbilical artery was noted (Figure 1a). In addition, the uterine artery waveform showed the typical appearance associated with FGR, with a high pulsatility index and notching (Figure 1b). Normotensive blood pressure, lack of peripheral pitting edema and absence of proteinuria excluded the possibility of pre-eclampsia. After detailed counseling, the woman opted to receive 25 mg sildenafil citrate three times daily for the treatment of FGR. Repeat ultrasonography 2 weeks after starting treatment revealed a decrease in uterine artery pulsatility index and resolution of notching in the Doppler waveform (Figure 1c). The estimated fetal weight had increased by approximately 100 g/week over 4 weeks of treatment, equal to the growth rate of uncomplicated pregnancies at 20–24 weeks' gestation. The fetal weight plateaued at 900 g at 30 weeks' gestation. Reversed end-diastolic velocity in the umbilical artery was observed at 32 + 6 weeks (Figure 1d) and a premature 912-g female was delivered via Cesarean-section en caul7, with Apgar scores of 4 and 7 at 1 and 5 min, respectively. Placental examination showed a small placenta (140 g) with a centrally-inserted umbilical cord. Cranial ultrasound examination did not show any intracranial hemorrhage or periventricular leukomalacia, and the neonatal course was uneventful at the time of writing. There are still limited data on the efficacy of sildenafil citrate for the treatment of FGR. Our case indicates its potential role in the treatment of early-onset FGR by reducing uterine artery impedance. Improvement of some aspects of placental hypoperfusion will help to prolong pregnancy. However, further fetal weight gain relies on solving the fundamental cause of FGR. Studies using sildenafil citrate during pregnancy have reported no deleterious effects on either the mother or offspring in animal models or human beings8. Further prospective clinical trials for the efficacy and safety of sildenafil citrate for FGR need to be conducted.
SDGs
Type
letter