Development of a core outcome set for research on critically ill obstetric patients

Introduction
Our objective was to develop a Core Outcome Set for Research on Critically Ill Obstetric Patients (COSCO) through international consensus, with the aim of improving consistency, comparability, and clinical relevance across studies involving this population.

Material and Methods
This international, multi-method study was conducted between February 16, 2023, and January 18, 2024. The process included a two-round online Delphi survey, three small group discussions, and a final consensus meeting. Participants comprised health service users (HSUs) with lived experience of critical illness during pregnancy and healthcare professionals from diverse specialties and geographic regions.

Results
Sixty-eight participants (11 HSUs and 57 healthcare professionals) from 16 countries scored 23 candidate items identified through a systematic review and qualitative interviews. Through consensus, 10 core outcomes and 7 reporting checklist items were selected for inclusion in all research on critical illness in obstetrics. Core outcomes included maternal all-cause mortality; cardiac arrest and the need for cardiopulmonary resuscitation (not resulting in death); severe (maternal) organ dysfunction; length of stay in the intensive care unit (ICU) and total hospital stay; readmission to hospital or ICU or repeated hospital/emergency department visits following discharge from ICU; presence of a new medical condition at the time of discharge from hospital, which was not present at the time of admission to the hospital; permanent infertility as a consequence of critical illness or intervention; perinatal loss; severe neonatal morbidity requiring prolonged neonatal ICU admission; and gestational age/preterm birth. Four additional noncore outcomes were identified as important but may be challenging to measure consistently; these should be reported when relevant and feasible.

Conclusions
COSCO provides a standardized, consensus-based framework for outcome reporting in research on critically ill obstetric patients. Its adoption will strengthen methodological rigor, reduce reporting heterogeneity, enhance comparability across studies, and support evidence-based, patient-centered guideline development.

Aim

It is estimated that critical illness affects pregnant women at a rate of 0.7 to 13.5/1,000 deliveries. Respiratory and cardiac physiology are altered during pregnancy, potentially affecting clinical management decisions. Critically ill pregnant women have been excluded or underrepresented in most interventional trials involving ICU patients, and the data specific to critial illness in pregnancy is limited and with heterogenous outcome reporting. Study outcomes important to the mother, child and family members have not been elucidated. The development of a core outcome set is vital to the conduct of prospective research in this important field.

Contributors

Stephen Lapinsky (PI), Intensive Care Unit, Mount Sinai Hospital and Interdepartmental Division of Critical Care, University of Toronto, Toronto, ON, Canada

Julien Viau-Lapointe, Interdepartmental Division of Critical Care, University of Toronto, Toronto, Canada

Collaborators :
Rohan D’Souza,Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, and Institute of Health Policy Management and Evaluation, Department of Medicine, University of Toronto, Toronto, Canada
Julia Kfouri, Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, University of Toronto, Toronto, Canada
Louise Rose, TD Nursing Professor in Critical Care Research, Sunnybrook Health Sciences Centre; Associate Professor, University of Toronto; and Research Director at Provincial Centre of Weaning Excellence, Toronto East General Hospital; Toronto, Canada

Julien Viau-Lapointe, Interdepartmental Division of Critical Care, University of Toronto, Toronto, Canada

Collaborators :
Rohan D’Souza,Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, and Institute of Health Policy Management and Evaluation, Department of Medicine, University of Toronto, Toronto, Canada
Julia Kfouri, Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, University of Toronto, Toronto, Canada
Louise Rose, TD Nursing Professor in Critical Care Research, Sunnybrook Health Sciences Centre; Associate Professor, University of Toronto; and Research Director at Provincial Centre of Weaning Excellence, Toronto East General Hospital; Toronto, Canada

Publication

Journal: Acta Obstetricia et Gynecologica Scandinavica
Volume:
Issue:
Pages: -
Year: 2026
DOI: https://doi.org/10.1111/aogs.70161

Further Study Information

Current Stage: Completed
Date: July 2017 - June 2018
Funding source(s): This work was supported by the CHEST Foundation Research Grant in Women's Lung Health awarded to Stephen E. Lapinsky.


Health Area

Disease Category: Lungs & airways, Pregnancy & childbirth

Disease Name: Critical illness

Target Population

Age Range: 16 - 54

Sex: Female

Nature of Intervention: Management of care

Stakeholders Involved

- Clinical experts
- Consumers (caregivers)
- Consumers (patients)
- Families
- Researchers
- Service providers
- Journal editors

Study Type

- COS for clinical trials or clinical research
- COS for practice

Method(s)

- Delphi process
- Focus group(s)
- Systematic review
- Consensus meeting

1. Identify outcomes that are currently reported in the published literature, through a systematic review.
2. Determine important outcomes through focus groups and Delphi study with an international group of patients, partners, carers and unrelated members of the public.
3. Determine important outcomes through a Delphi study with an international panel of expert physicians and allied health professionals.
4. Obtain a consensus through a final Delphi round involving all participants to create a core outcome set for future studies on the management of critical illness in pregnant women.