Reducing operative birth for fetal distress in women with small or suboptimally grown infants - The RidStress 2 Randomised Controlled Trial

Status

Recruiting

Phases

Phase 3

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12621000354886

Acronym

RIDSTRESS 2 (ReducIng fetal DiSTRESS in small or suboptimally grown infants)

Enrollment

200

Registered

2021-03-29

Start date

2021-07-28

Completion date

2026-09-11

Last updated

2024-09-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This is a 4-year Phase 3 RCT to re-purpose sildenafil citrate - a widely available, off-patent drug that dilates pelvic blood vessels and improves placental blood flow. The trial will evaluate whether, compared to Placebo, sildenafil citrate safely reduces emergency caesarean sections for fetal distress in small or suboptimally grown babies.

Interventions

Intrapartum Sildenafil Citrate 50mg taken orally, 8 hourly to a maximum of 3 doses (150mg) in 24 hours, given on one day only. Sildenafil Citrate will be given when the participant is admitted to the birthing unit for the commencement of induction of labour (artificial rupture of membranes +/- syntocinon infusion), or for management of spontaneous labour (regular uterine activity and >/= 4cm dilation on cervical assessment).

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

All

Age

18 Years to 50 Years

Healthy volunteers

Inclusion criteria

1. Singleton pregnancy 2. Planning a vaginal birth at term (>37 weeks gestation) 3. Aged >18 years and able to give informed consent 4. Pregnancy complicated by suspected small for gestational age (SGA) infant or late fetal growth restriction (FGR) (see below definitions) SGA is defined as Estimated Fetal Weight (EFW) or Abdominal Circumference (AC) <10th centile for gestation based on ultrasound assessment. FGR is defined as EFW or AC <3rd centile or two out of three of the following: 1. EFW or AC <10th centile. 2. AC or EFW crossing centiles by >two quartiles on growth charts. 3. Cerebroplacental ratio (CPR) <5th centile or Umbilical Artery Pulsatility Index (UA PI) >95th centile for gestation.

Exclusion criteria

1. Two or more previous CS births 2. Previous classical CS 3. Major fetal anomaly in this pregnancy 4. Non-cephalic presentation 5. Severe hepatic or renal impairment 6. Participants who are taking any type of nitrate drug therapy or who utilize short-acting nitrate-containing medications during labour [such as sodium nitroprusside, bosentan, fosamprenavir and ritonavir combination, hepatic enzyme inhibitors CYP3A4 (including itraconazole, ketoconazole, ritonavir, cimetidine, erythromycin, saquinavir, darunavir), or hepatic enzyme substrates (CYP3A4), medications used to treat pulmonary arterial hypertension, and other phosphodiesterase type 5 inhibitors like riociguat], due to the risk of potentially life-threatening hypotension.

Outcome results