Incidence and risk factors for umbilical cord prolapse in labor when amniotomy is used and with spontaneous rupture of membranes: A Swedish nationwide register study

Abstract

Introduction: Umbilical cord prolapse (UCP) is a rare but severe obstetric complication in the presence of a rupture of the membranes. Although it is not possible to prevent a spontaneous rupture of the membranes (SROM), it is possible to prevent an amniotomy, which is a commonly used intervention in labor. This study aimed to explore the incidence and risk factors that are associated with UCP in labor when amniotomy is used vs SROM. Material and methods: A retrospective nationwide register study was conducted of all births in Sweden from January 2014 to June 2020 that were included in the Swedish Pregnancy Register (n = 717 336). The main outcome, UCP, was identified in the data by the International Classification of Diseases (ICD-10) diagnosis code O69.0. Multiple binary logistic regression analysis was used to identify the risk factors. Results: Amniotomy was performed in 230 699 (43.6%) of all pregnancies. A UCP occurred in 293 (0.13%) of these cases. SROM occurred in 298 192 (56.4%) of all cases, of which 352 (0.12%) were complicated by UCP. Risk factors that increased the odds of UCP for both amniotomy and SROM were: higher parity, non-cephalic presentation and an induction of labor. Greater gestational age reduced the odds of UCP. Risk factors associated with only amniotomy were previous cesarean section and the presence of polyhydramnios. Identified risk factors for UCP in labor with SROM were a higher maternal age and maternal origin outside of the EU. Conclusions: UCP is a rare complication in Sweden. Beyond confirming the previously recognized risk factors, this study found induction of labor and previous cesarean section to be risk factors in labor when amniotomy is used.