Abnormal placental cord insertion and adverse pregnancy outcomes: a systematic review and meta-analysis
Ismail, Khadijah Irfah
BioMed Central Ltd.
Background: Abnormal placental cord insertion (PCI) includes marginal cord insertion (MCI) and velamentous cord insertion (VCI). VCI has been shown to be associated with adverse pregnancy outcomes. This systematic review and meta-analysis aims to determine the association of abnormal PCI and adverse pregnancy outcomes. Methods: Embase, Medline, CINAHL, Scopus, Web of Science, ClinicalTrials.gov, and Cochrane Databases were searched in December 2016 (from inception to December 2016). The reference lists of eligible studies were scrutinized to identify further studies. Potentially eligible studies were reviewed by two authors independently using the following inclusion criteria: singleton pregnancies, velamentous cord insertion, marginal cord insertion, and pregnancy outcomes. Case reports and series were excluded. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Outcomes for meta-analysis were dichotomous and results are presented as summary risk ratios with 95% confidence intervals. Results: Seventeen studies were included in the systematic review, all of which were assessed as good quality. Normal PCI and MCI were grouped together as non-VCI and compared with VCI in seven studies. Four studies compared MCI, VCI, and normal PCI separately. Two other studies compared MCI with normal PCI, and VCI was excluded from their analysis. Studies in this systematic review reported an association between abnormal PCI, defined differently across studies, with preterm birth, small for gestational age (SGA), low birthweight (< 2500 g), emergency cesarean delivery, and intrauterine fetal death. Four cohort studies comparing MCI, VCI, and normal PCI separately were included in a meta-analysis resulting in a statistically significant increased risk of emergency cesarean delivery for VCI (pooled RR 2.86, 95% CI 1.56–5.22, P = 0.0006) and abnormal PCI (pooled RR 1.77, 95% CI 1.33–2.36, P < 0.0001) compared to normal PCI. Conclusions: The available evidence suggests an association between abnormal PCI and emergency cesarean delivery. However, the number of studies with comparable definitions of abnormal PCI was small, limiting the analysis of other adverse pregnancy outcomes, and further research is required.
Abnormal placental cord insertion , Marginal placental cord insertion , Velamentous placental cord insertion , Adverse pregnancy outcomes , Small for gestational age , Emergency cesarean delivery
Ismail, K. I., Hannigan, A., O’Donoghue, K. and Cotter, A. (2017) 'Abnormal placental cord insertion and adverse pregnancy outcomes: a systematic review and meta-analysis', Systematic Reviews, 6, 242 (11pp). doi: 10.1186/s13643-017-0641-1
© 2017, the Authors. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.