USA 2016a.

Trial name or title	Efficacy of Sildenafil in preterm preeclampsia (SIL). ClinicalTrials.gov Identifier: NCT02782559
Methods	Double‐blind, placebo‐controlled RCT.
Participants	Target: 44. Hospitalised patients of gestational age of ≥ 24 0/7 weeks to ≤ 32 0/7 weeks; dating of pregnancy by ultrasound < or equal to 22 weeks or IVF conception and diagnosis of preterm pre‐eclampsia or superimposed pre‐eclampsia.
Interventions	Treatment arm: sildenafil 40 mg oral tablet 3 times a day from randomisation until delivery. Control arm: matched to oral capsule of active treatment 3 times a day from randomisation until delivery.
Outcomes	Primary outcomes: duration of pregnancy from diagnosis/randomisation until delivery. Secondary outcomes: not reported.
Starting date	July 2016
Contact information	The University of Texas Health Science Center, Houston ‐ USA Contact: Robyn P Roberts, MD (734‐934‐4227) Robyn.P.Roberts@uth.tmc.edu Contact: Maria Hutchinson (713‐500‐0510) Maria.S.keefer@uth.tmc.edu
Notes	Ongoing.