Comparative Risk of Neonatal Ischemic Encephalopathy in Operative Vaginal Delivery versus Cesarean Section at Complete Dilation: A Systematic Review and Meta-analysis

Abstract

Objective

The objective of this study is to assess the risk of neonatal hypoxic–ischemic encephalopathy (HIE) associated with operative vaginal delivery (OVD) compared with cesarean delivery at complete cervical dilation (CDCD) and spontaneous vaginal delivery (SVD), with subgroup analyses by OVD type (vacuum- and forceps-assisted).

Study Design

PubMed, Cochrane Library, Web of Science, Medline, ClinicalTrials.gov, and Scopus were searched from inception to October 1, 2024. Cohort studies reporting HIE incidence in OVD (vacuum or forceps) compared with CDCD or SVD were included. Data were extracted by two independent reviewers following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) guidelines. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using random-effects models. Primary outcomes were HIE incidence in OVD versus SVD and CDCD. Secondary outcomes included HIE risk by OVD type (vacuum- vs. forceps-assisted).

Results

Five studies (141,774 deliveries) met the inclusion criteria. OVD was associated with a significantly higher HIE risk compared with SVD (RR: 3.36, 95% CI: 2.52–4.50, p < 0.001). No significant difference was observed between OVD and CDCD (RR: 0.77, 95% CI: 0.50–1.19, p = 0.24). Subgroup analysis showed forceps-assisted delivery had a lower HIE risk compared with CDCD (RR: 0.29, 95% CI: 0.15–0.43, p < 0.001), whereas vacuum-assisted delivery showed no significant difference (RR: 0.89, 95% CI: 0.56–1.42, p = 0.63).

Conclusion

OVD is associated with a higher HIE risk than SVD but not CDCD. Forceps-assisted delivery may reduce HIE risk compared with CDCD, unlike vacuum-assisted delivery. These findings highlight the importance of careful delivery method selection when SVD is not feasible, balancing risks and benefits to optimize neonatal outcomes.

Key Points

• OVD raises HIE risk versus SVD but not CDCD in 141,774 deliveries.

• Forceps-assisted delivery lowers HIE risk versus CDCD (RR = 0.29).

• First meta-analysis comparing HIE in OVD, CDCD, and SVD.

Keywords

neonatal hypoxic–ischemic encephalopathy - operative vaginal delivery - cesarean section - forceps-assisted delivery

Contributors' Statement

K.S.: conceptualization, formal analysis, writing—original draft, writing—review and editing. D.G.: data curation, methodology, validation. B.H.: data curation, methodology, supervision. K.R.: Data curation, Formal analysis. M.R.: Data curation, Methodology, Validation. E.K.: data curation, formal analysis, writing—original draft. S.M.: data curation, Formal analysis, Writing—original draft. N.P.: data curation, formal analysis, validation. G.J.M.: data curation, formal analysis, visualization.

Ethical Approval

This manuscript has been reviewed by the institutional IRB board at Marchand Institute and was found to be exempt from IRB review (November 2024).

Clinical Trial Registration

This study was registered with Prospero (registration no.: CRD42025640584).

Informed Consent

Data used were exempt from consent to participate or publish secondary to the nature of the study being a systematic review, retrospectively looking at previously published data.

Note

The Marchand Institute remains committed to diversity and tolerance in its research and actively maintains a workplace free of racism and sexism. Greater than half of the authors for this study are female, and many represent diverse backgrounds and underrepresented ethnic groups.

Publication History

Received: 20 June 2025

Accepted: 23 January 2026

Accepted Manuscript online:
28 January 2026

Article published online:
20 February 2026

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