Mater Research Institute The University of Queensland, South Brisbane, Queensland, Australia.
Women's and Newborn Services, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
BMJ Open. 2024 Sep 25;14(9):e082945. doi: 10.1136/bmjopen-2023-082945.
Small for gestational age (SGA) infants are at increased risk of fetal distress in labour requiring emergency operative birth (by caesarean section (CS), vacuum or forceps). We have previously shown that maternal oral sildenafil citrate (SC) in labour halves the need for operative birth for suspected fetal distress in women with appropriately grown term infants.
RidStress 2 is a phase III randomised, double-blinded, placebo-controlled trial of 660 women with an SGA or suboptimally grown fetus (estimated fetal weight or abdominal circumference<10th centile for gestational age) planning a vaginal birth at term. The trial will determine whether oral intrapartum SC (50 mg eight hourly) reduces the relative risk of emergency CS for fetal distress compared with placebo. The primary outcome is CS for fetal distress, and the secondary outcomes are any operative birth for fetal distress, cost-effectiveness of SC treatment and 2-year childhood neurodevelopmental outcomes. To detect a 33% reduction in the primary outcome from 30% to 20% for an alpha of 0.05 and power of 80% with 10% dropout, requires approximately 660 women (330 in each arm). This sample size will also yield >90% power to detect a similar reduction for the secondary outcome of any operative birth (CS or instrumental vaginal birth) for fetal distress.
Ethics approval was granted by the Mater Misericordiae Limited Human Research Ethics Committee (EC00332) on 11 September 2020. We plan to disseminate the results of this randomised controlled trial through presentations at scientific meetings and peer-reviewed journals, adhering to all relevant reporting guidelines.
RidStress 2 is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000354886, 29/03/2021) and the Therapeutic Goods Association of Australia (date registered: 16 March 2021).
小于胎龄儿（SGA）在分娩时发生胎儿窘迫的风险增加，需要紧急手术分娩（剖宫产、真空吸引或产钳）。我们之前的研究表明，对于适当生长的足月婴儿的产妇，在分娩时口服西地那非枸橼酸盐（SC）可将疑似胎儿窘迫的手术分娩需求减半。
RidStress 2 是一项三期随机、双盲、安慰剂对照试验，纳入 660 名 SGA 或胎儿生长不理想（估计胎儿体重或腹围<胎龄第 10 百分位数）的计划经阴道足月分娩的女性。该试验将确定在分娩时口服西地那非（50mg 每 8 小时）是否可降低因胎儿窘迫而行紧急剖宫产的相对风险，与安慰剂相比。主要结局是因胎儿窘迫而行剖宫产，次要结局是任何因胎儿窘迫而行的手术分娩、SC 治疗的成本效益以及 2 岁儿童神经发育结局。为了检测从 30%到 20%的主要结局的 33%的降低，需要约 660 名女性（每组 330 名），alpha 值为 0.05，效能为 80%，失访率为 10%。这个样本量也将有超过 90%的效能来检测因胎儿窘迫而进行的任何手术分娩（剖宫产或器械性阴道分娩）的次要结局的类似降低。
Mater Misericordiae Limited 人类研究伦理委员会于 2020 年 9 月 11 日批准了这项伦理审查（EC00332）。我们计划通过在科学会议和同行评议期刊上的演讲来传播这项随机对照试验的结果，遵循所有相关的报告指南。
RidStress 2 已在澳大利亚和新西兰临床试验注册中心（ACTRN12621000354886，2021 年 3 月 29 日）和澳大利亚治疗商品协会（注册日期：2021 年 3 月 16 日）注册。
