Pregnancy ComplicationsNCT02866058

Outcomes of Cesarean Section vs Vaginal Delivery: Instrumental Variable Adjusted Analysis

An observational study of Pregnancy Complications and Cesarean Section, run by Memorial University of Newfoundland.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

This study will examine the effect of cesarean section on perinatal mortality, using data provided by the Canadian Institute for Health Information. Read more about this study

Who is it for?: Any ageHealthy volunteers can take part
Conditions the study is for: Pregnancy Complications, Cesarean Section
What is being tested?: Cesarean Section
Type of treatment: Surgery or procedure
How many people: 836,755 participants
Where: No sites listed yet
Study dates: May 2011to Jul 2015
Phase: Observational
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages Any age
All sexes
Healthy volunteers accepted
Child, Adult, Older adult

Study population: All obstetrical deliveries in Canada (except the province of Quebec) between April 1, 2006 and March 31, 2009

Who may be able to join

Infants born within the study period at Canadian hospitals outside of the province of Quebec.

Who cannot join

Infant record not linkable to maternal record.
Birthweight < 500 gm.
Gestational age at delivery < 20 weeks.
Deliveries at hospitals with less than 20 cesarean deliveries during study period.
Records with missing data for important covariates

About this study

Official title: Substantial Variability Between Traditional and Instrumental Variable Estimates of the Risk of Caesarean Section in Canada: a Population-based Cohort Study

This study will examine the effect of cesarean section on perinatal mortality, using data provided by the Canadian Institute for Health Information.

Read the detailed description

This study will examine administrative data provided by the Canadian Institute for Health Information (CIHI). Maternal obstetrical delivery and neonatal hospitalization records provided by CIHI will be linked before analysis. The primary outcome is in-hospital perinatal mortality. The data will be analyzed by traditional multi-variate logistic regression, and the results from this analysis will be compared to the results from instrumental variable adjusted regression using the Generalized Method of Moments. The instrumental variable is the rate of cesarean delivery among women living within the same hospital catchment area. All analyses will be adjusted for maternal, infant, delivery provider, and hospital factors, as well as for clustering at the level of the delivery hospital.

Conditions: Pregnancy Complications, Cesarean Section
Being tested: Cesarean Section
Medical subject headings: Pregnancy Complications

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Cesarean SectionProcedure or surgery

Study groups in NCT02866058
Study group	Role	What they receive
Cesarean		Infants delivered by cesarean section Receives: Procedure: Cesarean Section
Vaginal		Infants delivered by vaginal delivery

What is being measured

The primary outcome is the main question the study is designed to answer.

Perinatal Mortality
Infant death during the Outcome Measure Time Frame.
Measured: Newborn infants were followed for 7 days after birth or until discharge from the hospitalization at which birth occurred, whichever was longer. If infants were continuously hospitalized, they were followed to end of study period for a maximum of 3 years.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

May 2011Jul 2015

First posted15 Aug 2016 (estimated)
Study startMay 2011
Primary completionJul 2013
Study completionJul 2015

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Pregnancy ComplicationsStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Observational
Observational model: Cohort
Time perspective: Retrospective
Enrolment: 836,755 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT02866058
Sponsor's protocol ID: MRFCoxAwardAubrey2
Status last verified: Oct 2026
First submitted: 4 Aug 2016
Last updated: 28 Oct 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
Individual data sharing: No: The data provider does not allow sharing of investigator data, but data can be requested directly from them.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

Official record

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All Pregnancy Complications trials

Study at a glance

From the registry record, last updated by the sponsor on 28 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Substantial Variability Between Traditional and Instrumental Variable Estimates of the Risk of Caesarean Section in Canada: a Population-based Cohort Study
ClinicalTrials.gov ID: NCT02866058
Acronym / sponsor ID: MRFCoxAwardAubrey2
Conditions: Pregnancy Complications, Cesarean Section
Study type: Observational
Recruitment status: Completed
Enrolment: 836,755 participants (actual)
Lead sponsor: Memorial University of NewfoundlandUniversity, hospital or other
Collaborators: Medical Research Foundation - Memorial University
Study start: May 2011
Primary completion: Jul 2013 (actual)
Study completion: Jul 2015 (actual)
First posted: 15 Aug 2016 (estimated)
Results: Posted 28 Oct 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

This study will examine the effect of cesarean section on perinatal mortality, using data provided by the Canadian Institute for Health Information.

Detailed description

Study design

Observational model: Cohort
Time perspective: Retrospective
Number of arms: 2

Arm	Type	Receives
Cesarean	–	Procedure: Cesarean SectionInfants delivered by cesarean section
Vaginal	–	–Infants delivered by vaginal delivery

Who may qualify

Sex: All
Healthy volunteers: Accepted
Age groups: Child, Adult, Older adult
Study population: All obstetrical deliveries in Canada (except the province of Quebec) between April 1, 2006 and March 31, 2009

Key inclusion criteria (1 listed)

Infants born within the study period at Canadian hospitals outside of the province of Quebec.

Key exclusion criteria (5 listed)

Infant record not linkable to maternal record.
Birthweight < 500 gm.
Gestational age at delivery < 20 weeks.
Deliveries at hospitals with less than 20 cesarean deliveries during study period.
Records with missing data for important covariates

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Cesarean Section	Procedure or surgery	Cesarean

Primary outcome

Perinatal Mortality
Time frame: Newborn infants were followed for 7 days after birth or until discharge from the hospitalization at which birth occurred, whichever was longer. If infants were continuously hospitalized, they were followed to end of study period for a maximum of 3 years.
Infant death during the Outcome Measure Time Frame.

Results and safety

Results posted to the registry on 28 Oct 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Cesarean	237,239	237,239
Vaginal	599,516	599,516

Primary outcome: Perinatal Mortality

Time frame: Newborn infants were followed for 7 days after birth or until discharge from the hospitalization at which birth occurred, whichever was longer. If infants were continuously hospitalized, they were followed to end of study period for a maximum of 3 years.. Count of participants. Unit: Participants

Measure	Cesarean n = 237239	Vaginal n = 599516
Value	1202	2484

Cesarean vs Vaginal: Risk Ratio (RR): 0.53 (95% CI 0.47 to 0.60), p <0.001, Regression, Logistic
Cesarean vs Vaginal: Risk Ratio (RR): 1.54 (95% CI 0.06 to 38.9), p <0.05, IV- adjusted logistic regression

Population analysed: Participants who had complete study data

Adverse events

Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Cesarean	0 of 0	0 of 0	Not reported
Vaginal	0 of 0	0 of 0	Not reported

Limitations and caveats (from the sponsor): This study analyzes administrative data. The only outcome measured was perinatal mortality. Maternal morbidity and mortality were not assessed.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No. The data provider does not allow sharing of investigator data, but data can be requested directly from them.

Related trials for Pregnancy Complications

Recruiting
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Gynaecological Cancers, Ovarian Cancer
RecruitingPhase 1/2
Study of INBRX-106 and INBRX-106 in Combination With Pembrolizumab (Keytruda®) in Subjects With Locally Advanced or Metastatic Solid Tumors (Hexavalent OX40 Agonist)
Solid Tumor, Non-Small Cell Lung Cancer
RecruitingObservational study
Population Pharmacokinetics of Temocillin in Acute Enterobacterial Pyelonephritis in Children
Pyelonephritis
Active, not recruitingPhase 3
A Study of Belzutifan (MK-6482) in Combination With Lenvatinib Versus Cabozantinib for Treatment of Renal Cell Carcinoma (MK-6482-011)
Carcinoma, Renal Cell
Recruiting
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Urinary Incontinence, Urinary Incontinence, Urge

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Kris Aubrey-Bassler, MD principal investigator

Memorial University

Questions about this trial

What is this clinical trial studying?

An observational study of Pregnancy Complications and Cesarean Section, run by Memorial University of Newfoundland.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 28 Oct 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Perinatal Mortality (time frame: Newborn infants were followed for 7 days after birth or until discharge from the hospitalization at which birth occurred, whichever was longer. If infants were continuously hospitalized, they were followed to end of study period for a maximum of 3 years.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT02866058.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.