A study protocol for the cardiac effects of a single dose of either oxytocin 2.5 IU or carbetocin 100 µg after caesarean delivery: a prospective randomized controlled multi-centre trial in Norway

F1000Res. 2021 Sep 27:10:973. doi: 10.12688/f1000research.73112.2. eCollection 2021.

Abstract

Background: Both oxytocin and carbetocin are used to prevent uterine atony and post-partum haemorrhage after caesarean delivery in many countries, including Norway. Oxytocin causes dose-dependent ST-depression, troponin release, prolongation of QT-time and arrythmia, but little is known about myocardial effects of carbetocin. We have previously demonstrated comparable vasodilatory effects of oxytocin and carbetocin and are now undertaking a Phase 4 trial to investigate whether carbetocin causes similar changes to myocardial markers compared with oxytocin. Methods: Our randomized controlled trial will be conducted at three obstetrics units at Oslo University Hospital and Akershus University Hospital, Norway. Planned enrolment will be of 240 healthy, singleton pregnant women aged 18 to 50 years undergoing planned caesarean delivery. Based on pilot study data, each participant will receive a one-minute intravenous injection of either oxytocin 2.5 IU or carbetocin 100 µg during caesarean delivery. The prespecified primary outcome is the change from baseline in high-sensitive troponin I plasma concentrations at 6-10 hours after study drug administration. Secondary outcomes include uterine tone grade at 2.5 and five minutes after study drug administration, adverse events for up to 48 hours after study drug administration, estimated blood loss within eight hours of delivery, need for rescue treatment and direct/indirect costs. Enrolment and primary analysis are expected to be completed by the end of 2021. Discussion: Women undergoing caesarean delivery should be assessed for cardiovascular risk particularly as women with an obstetric history of pregnancy induced hypertension, gestational diabetes mellitus, preterm birth, placental abruption, and stillbirth are at increased risk of future cardiovascular disease. Any additional ischaemic myocardial risk from uterotonic agents will need to be balanced with the benefit of reducing the risk of postpartum haemorrhage. Any potential cardiotoxicity difference between oxytocin and carbetocin will help inform treatment decisions for pregnant women. Registration: Clinicaltrials.gov NCT03899961 (02/04/2019).

Keywords: Oxytocin; anaesthesia; caesarean delivery; carbetocin; troponin I; uterine atony.

Publication types

  • Clinical Trial Protocol

MeSH terms

  • Cesarean Section / adverse effects
  • Female
  • Humans
  • Infant, Newborn
  • Multicenter Studies as Topic
  • Oxytocics* / adverse effects
  • Oxytocin / adverse effects
  • Oxytocin / analogs & derivatives
  • Pilot Projects
  • Placenta
  • Postpartum Hemorrhage* / drug therapy
  • Postpartum Hemorrhage* / etiology
  • Postpartum Hemorrhage* / prevention & control
  • Pregnancy
  • Premature Birth* / drug therapy
  • Premature Birth* / etiology
  • Prospective Studies
  • Randomized Controlled Trials as Topic

Substances

  • Oxytocics
  • Oxytocin
  • carbetocin

Associated data

  • ClinicalTrials.gov/NCT03899961

Grants and funding

Oslo University Hospital and Akershus University Hospital provided the majority of financial support for this investigator-led study. The manufacturer of Carbetocin (Pabal®), Ferring Pharmaceuticals, St-Prex, Switzerland, supported the trial with an unrestricted grant to Oslo University Hospital, Norway, (grant number 37932). The manufacturer did not influence the study design or the decision to publish the protocol. The unrestricted grant provided financial support for the trial nurses, insurance, biobank costs, laboratory analyses and other running expenses. Ferring Pharmaceuticals funded medical writing support for this manuscript.