Results
The study flow diagram was demonstrated in Figure 2. Among 1017 cases of CP from the JOCSC database, 131 were considered to be associated with umbilical cord troubles in singleton pregnancies. Five cases were excluded because of uninterpretable or missing FHR data, and 126 cases were analyzed.
The characteristics of our study cohort were shown in Table 1. 24.6% were complicated with preterm premature rupture of membranes, the trans-cervical balloon catheter was used for cervical ripening in 17.5%, and most cases were delivered by the emergency cesarean section (63.5%). More than half in the umbilical cord arterial pH was no less than 7.0 (57.8%). However, the Apgar scores were lower than normal in most CP cases (Apgar score <7: at 1 min, 96.8%; at 5 min, 83.9%, respectively)
The FHR classifications and those stratified by the umbilical cord troubles are shown in Figures 3 and 4. Overall, nearly half of CP caused by umbilical cord troubles occurred with a sudden evolution pattern during delivery (R-PD, 43%). On the contrary, approximately one-third of those showed abnormal FHR patterns on admission (P-Brady and P-NR, 33%). The FHR class analysis divided by umbilical cord prolapse and the other morphological abnormalities showed that nearly 90% of CP due to umbilical cord prolapse developed FHR deterioration during labor, particularly with R-PD. Meanwhile, approximately 40% of those associated with cord morphological abnormalities had already shown abnormal FHR patterns on admission, mostly persistently non-reassuring patterns.
Timing and type of evolution patterns of abnormal FHR stratified by umbilical cord troubles are demonstrated in Table 2. In cases of various umbilical cord abnormalities, such as velamentous insertion, true knots, constriction, and hyper-coiled cords, around half of the patients already had FHR alterations at the time of admission. In terms of the intrapartum onset, most FHR deteriorations occurred during the first stage of labor in all types of cord troubles. Furthermore, most patients complicated with velamentous insertion and multiple entanglements developed CP with Hon’s pattern.