Umbilical cord coiling index for the prediction of adverse pregnancy outcomes: a meta-analysis and sequential analysis

AbstractPurpose: To evaluate the potential association of abnormal cord coiling with adverse pregnancy outcomes.Materials and methods: We used the Medline (1966–2018), Scopus (2004–2018), Clinicaltrials.gov (2008–2018), Embase (1980–2018), Cochrane Central Register of Controlled Trials CENTRAL (1999–2018), and Google Scholar (2004–2018) databases. The date of last search was set on 31 May 2018. Language, country, or date restrictions were not applied during the literature research to prevent bias. All observational (both prospective and retrospective) studies that reported maternal and neonatal antenatal and perinatal outcomes based on the umbilical coiling index (UCI) status were considered as eligible for inclusion. Meta-analysis of the risk ratio (RR) and mean differences (MD) among hypocoiled/hypercoiled and normocoiled cases was performed with RevMan 5.3 software. Univariate metaregression and leave-one-out meta-analysis was performed with Open Meta-Analyst statistical software. Trial sequential anal...