Impact of marginal cord insertion on perinatal outcomes: A systematic review and meta-analysis

Published:January 25, 2023DOI:



      Despite its high prevalence and the possible link with perinatal complications, marginal cord insertion (MCI) is surrounded by considerable controversy regarding management. Our aim through this meta-analysis was to study its association with several perinatal outcomes in a manner that provides trustworthy and exact effect measures, enabling us eventually to evaluate its overall risk for pregnancy.

      Data sources

      A systematic search was performed in Medline, Scopus, and the Cochrane Library as of 30th July 2022 to identify eligible studies.

      Study eligibility criteria

      Observational studies including singleton pregnancies and comparing MCI to central/eccentric cord insertion (CCI), either prenatally or postnatally identified, were considered eligible.

      Study appraisal and synthesis methods

      The Newcastle-Ottawa scale was used to assess study quality, and the QUIPS tool was used to assess bias risk. The main outcome was small for gestational age (SGA) neonates. Q test and an I2 score were used to assess study heterogeneity. The analyses were carried out using random-effects model, and the results were expressed as relative risk or mean difference with a 95% confidence interval.


      In total, 15 studies (13 cohort studies and two case-control studies) contributed data to the analysis. In seven of these, there was a prenatal and in eight a postnatal diagnosis. The overall prevalence of MCI was 6.15% (1.13-11.3%). MCI pregnancies compared to CCI ones were found to be at higher risk of SGA neonates (RR: 1.25; 95% CI:1.21-1.29), preeclampsia (RR: 1.61; 95% CI:1.54-1.67), placental abruption (RR: 1.53; 95% CI:1.34-1.75), stillbirth (RR: 1.97; 95% CI:1.02-3.78), preterm delivery (RR: 1.47; 95% CI:1.24-1.75), lower mean gestational age at birth (MD: -0.20; 95% CI: -0.38 to -0.01), emergency cesarean delivery (RR: 1.39; 95% CI:1.35-1.44), lower mean birthweight (MD: -139.19; 95% CI: -185.78 to -92.61), 5-minute Apgar score <7 (RR: 1.48; 95% CI:1.00-2.19) and neonatal intensive care unit admission (RR: 1.57; 95% CI:1.20-2.06). When only prenatally diagnosed MCI pregnancies were considered, the risk remained high regarding SGA (RR: 1.34; 95% CI:1.21-1.48), preeclampsia (RR: 1.42; 95% CI:1.01-1.99), stillbirth (RR: 2.99; 95% CI:1.03-8.70), preterm delivery (RR: 1.41; 95% CI:1.19-1.68), lower mean gestational age at birth (MD: -0.22; 95% CI: -0.33 to -0.11) and lower mean birthweight (MD: -122.41; 95% CI: -166.10 to -78.73).


      Through this analysis the higher risk that MCI poses for pregnancy, regarding several adverse outcomes, became evident. Many of these associations persisted among the prenatally diagnosed pregnancies. The underlining pathophysiology should be investigated and further research is needed on the effect of increased surveillance in improving perinatal outcomes.


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