Sildenafil Citrate to Improve Maternal and Neonatal Outcomes in Low-resource Settings

Inclusion Criteria: * Admission to facility with plan for spontaneous or induced vaginal delivery * Early stage of labor (≤ 6 cm cervical dilation per local standard) at ≥ 37 weeks gestation * Age ≥ 18 years of age * Presence of single live fetus confirmed via a fetal heart rate by Doptone in cephalic position * Provision of written informed consent \[Note: if written consent is obtained at an early time, verbal re-confirmation is required at time of enrollment\] Exclusion Criteria: * Non-emancipated minors (as per local regulations) * Plan for Cesarean delivery or history of cesarean section prior to enrollment\* * Unknown gestational age * Advanced stage of labor (\>6 cm or 10 cm cervical dilation per local standards) and pushing or too distressed to understand, confirm, or give informed consent regardless of cervical dilation * Not capable of giving consent due to other health problems such as obstetric emergencies (for example, antepartum hemorrhage) or mental disorder; * Any medical condition considered a contraindication, including contraindication to sildenafil therapy, per the judgement of site investigators * Any maternal medical condition or status that precludes informed consent * Recognized fetal anomaly