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Updated: Jan 30, 2026

A Piglet Model of Neonatal Hypoxic-Ischemic Encephalopathy
Published on: May 16, 2015
Comparative Risk of Neonatal Ischemic Encephalopathy in Operative Vaginal Delivery versus Cesarean Section at
Katelyn Marie Sainz1, Daniela Gonzalez2, Brooke Hamilton2
1Department of Neonatology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, United States.
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..
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