The Effects of Sildenafil on Fetal Doppler Indices: A Systematic Review and Meta-Analysis

 Background & Objective:  Sildenafil citrate is a potential new strategy for the management of intrauterine growth restriction (IUGR) and preeclampsia, although its efficacy still needs to be approved. Accordingly, the aim of this study was to systematically assess the effectiveness of sildenafil on improving fetal Doppler indices, as well as the most common adverse effects of sildenafil.   Materials & Methods:  Online databases, i.e., PubMed, Web of Science, Scopus, Embase, and Cochrane Reviews, were searched from their date of creation up to 26 Jan 2019. We conducted two meta-analyses, one for fetal Doppler indices and the other for adverse events of sildenafil. Eligible studies were randomized controlled trials (RCTs), in which the effects of sildenafil on fetal Doppler indices have been evaluated. The quality of studies was appraised through the five components of the Cochrane checklist (for quality appraisal of RCT studies) by two of the authors. Results:  Out of 1,087 reviewed sources, seven studies were included for meta-analysis. The following results were observed for the effect of sildenafil on the umbilical artery (UA): A significant effect on the umbilical artery pulsatility index (UA PI) (P=0.03) was observed in dosages more than 60 mg/d (P=0.008). Sildenafil was effective in UA PI of the individuals suffering from eclampsia (P=0.008); however, no significant effect was observed on IUGR disorder. Furthermore, sildenafil had no effect on the umbilical artery systolic/diastolic (UA S/D) ratio. Sildenafil was not effective on the middle cerebral artery pulsatility index (MCA PI) or on the middle cerebral artery systolic/diastolic (MCA S/D) ratio. Regarding adverse events, headaches occurred significantly more in mothers consuming sildenafil (P=0.03).  Conclusion:  Obviously, we need more accurate RCTs in this issue before any decision can be made.