Umbilical cord prolapse: revisiting its definition and management.

Umbilical cord prolapse is an unpredictable obstetrical emergency with an incidence ranging from 1 to 6 per 1000 pregnancies. It is associated with high perinatal mortality, ranging from 23% to 27% in low-income countries to 6% to 10% in high-income countries. In this review, we specifically addressed 3 issues. First, its definition is not consistent in the current literature, and "occult cord prolapse" is a misnomer because the cord is still above the cervix. We proposed that cord prolapse, cord presentation, and compound cord presentation should be classified according to the positional relationship among the cord, the fetal presenting part, and the cervix. All of them may occur with either ruptured or intact membranes. The fetal risk is highest in cord prolapse, followed by cord presentation, and lastly by compound cord presentation, which replaces the misnomer "occult cord prolapse." Second, the mainstay of treatment of cord prolapse is urgent delivery, which means cesarean delivery in most cases, unless vaginal delivery is imminent. The urgency depends on the fetal heart rate pattern, which can be bradycardia, recurrent decelerations, or normal. It is most urgent in cases with bradycardia, because a recent study showed that cord arterial pH declines significantly with the bradycardia-to-delivery interval at a rate of 0.009 per minute (95% confident interval, 0.0003-0.0180), and this may indicate an irreversible pathology such as vasospasm or persistent cord compression. However, cord arterial pH does not correlate with either deceleration-to-delivery interval or decision-to-delivery interval, indicating that intermittent cord compression causing decelerations is reversible and less risk. Third, while cesarean delivery is being arranged, different maneuvers should be adopted to relieve cord compression by elevating the fetal presenting part and to prevent further cord prolapse beyond the vagina. A recent study showed that the knee-chest position provides the greatest elevation effect, followed by filling of the maternal urinary bladder with 500 mL of fluid, and then the Trendelenburg position (15°) and other maneuvers. However, each maneuver has its own advantages and limitations; thus, they should be applied wisely and with great caution, depending on the actual clinical situation. Therefore, we have proposed an algorithm to guide this acute management.

Bradycardia-to-delivery interval and fetal outcomes in umbilical cord prolapse.

INTRODUCTION: Umbilical cord prolapse is a major obstetric emergency associated with significant perinatal complications. However, there is no consensus on the optimal decision-to-delivery interval, as many previous studies have shown poor correlation between the interval and umbilical cord arterial blood gas or perinatal outcomes. We aim to investigate whether bradycardia-to-delivery or decision-to-delivery interval was related to poor cord arterial pH or adverse perinatal outcome in umbilical cord prolapse. MATERIAL AND METHODS: This was a retrospective study conducted at a university tertiary obstetric unit in Hong Kong. All women with singleton pregnancy complicated by cord prolapse during labor between 1995 and 2018 were included. Women were categorized into three groups. Group 1: persistent bradycardia; Group 2: any type of decelerations without bradycardia; and Group 3: normal fetal heart rate. The main outcome was cord arterial blood gas results of the newborns in different groups. Maternal demographic data and perinatal outcomes were reviewed. Correlation analysis between cord arterial blood gas result and time intervals including bradycardia-to-delivery, deceleration-to-delivery, and decision-to-delivery were performed for the different groups with Spearman test. RESULTS: There were 34, 30, and 50 women in Groups 1, 2, and 3, respectively. Cord arterial pH and base excess did not correlate with decision-to-delivery interval in any of the groups, but they were inversely correlated with bradycardia-to-delivery interval in Group 1 (Spearman's ρ = -.349; P = .043 and Spearman's ρ = -.558; P = .001, respectively). The cord arterial pH drops at 0.009 per minute with bradycardia-to-delivery interval in Group 1 (95% CI 0.0180-0.0003). The risk of significant acidosis (pH < 7) was 80% when bradycardia-to-delivery interval was >20 minutes, and 17.2% when the interval was <20 minutes. CONCLUSIONS: There is significant correlation between bradycardia-to-delivery interval and cord arterial pH in umbilical cord prolapse with fetal bradycardia but not in cases with decelerations or normal heart rate. The drop of cord arterial pH is rapid and urgent delivery is essential in such situations.