Phosphodiesterase-5 inhibitors in pregnancy: Systematic review and meta-analysis of maternal and perinatal safety and clinical outcomes

Background: The efficacy and safety profile of phosphodiesterase-5 inhibitors (PDE-5i) in pregnancy are unclear from the few relatively small diverse studies that have used them. Objective: To assess the safety profile and clinical outcomes of PDE-5i use in pregnancy. Search strategy: We searched Embase, PubMed, CENTRAL, Prospero and Google Scholar to identify randomised controlled trials (RCTs) reporting the use of any PDE-5i in pregnancy up to September 2021. Selection criteria: RCTs reporting obstetric or perinatal outcomes or maternal adverse outcomes in women taking PDE5i in pregnancy. Data collection and analysis: Risk ratios (RR), 95% confidence intervals (95% CI) and 95% prediction intervals were calculated and pooled for analysis. Results: We identified 1324 citations, of which 10 studies including 1090 participants met the inclusion criteria. Only tadalafil and sildenafil were reported as used in pregnancy. Two studies using tadalafil and eight sildenafil. Nine of ten studies were assessed at having of low risk of bias. PDE-5i use was associated with an increased risk of headaches (RR 1.41, 95% CI 0.97–2.05), flushing (RR 2.59, 95% CI 0.69–9.90) and nasal bleeding (RR 10.53, 95% CI 1.36–81.3); an increase in vaginal birth when used for non-fetal growth restriction (FGR) indications (RR 1.24, 95% CI 1.00–1.55) and a reduction in risk of operative birth for intrapartum fetal compromise (RR 0.58, 95% CI 0.38–0.88). There was no evidence of any increase in risk of perinatal death (RR 0.89, 95% CI 0.56–1.43). However, use for the treatment of FGR increased the risk of persistent pulmonary hypertension of the newborn (PPHN) (RR 2.52, 95% CI 1.00–6.32). Conclusions: This meta-analysis suggests PDE-5i use in pregnancy is associated with mild maternal side effects and lower risk of operative birth for intrapartum fetal distress. Prolonged use for the treatment of FGR may increase the risk of PPHN.