Interpretation
Concurring with the previous report,5 severe CP caused
by umbilical cord troubles, especially cord prolapse, was characterized
by a sudden onset (R-PD) in the intrapartum. It is not surprising, given
these configurations of the umbilical cord lead to vulnerability to
compression or torsion during uterine
contractions.12,13 In contrast, we identified a high
incidence of CP associated with cord morphological abnormalities
developed in an antenatal period, mostly P-NR accounted for 36%. The
hyper-coiled cord is reported to be more prone to torsion rather than
compression or stretching.14,15 Furthermore, several
histological studies showed the association between umbilical cord
abnormalities and placental circulatory stasis or
thrombosis.2,16,17 Such a cumulative effect on
fetoplacental blood flow may result in antenatal etiology of brain
injury.
We identified that most FHR deteriorations occurred during the first
stage of labor and a high incidence of Hon’s pattern in the case with
umbilical cord structural lesions such as velamentous insertion and
multiple entanglements. Several retrospective studies showed the
association of variable decelerations during the first stage of labor
with umbilical cord abnormalities such as velamentous cord insertion and
hyper-coiled cord.18,19 Moreover, a prospective study
showed that morphological abnormalities developed in the earlier
gestation were likely to coexist with placental abnormalities that
affect the fetoplacental perfusion during labor.20Such cumulative distress described above might also arise during
repetitive uterine contractions and could develop Hon’s pattern. As this
pattern evolves over several hours, we may be able to intervene and
correct the FHR pattern before severe hypoxia occurs. Therefore,
morphological abnormalities of the umbilical cord have the potential of
predicting such FHR alterations, and ultrasound screening for them
antenatally is crucial to predispose labor and delivery care providers
to greater focus on Hon’s FHR progression.
On the other hand, the prevention of CP in cases with R-PD might be
difficult. A previous nationwide study on the prognosis of infants with
umbilical cord prolapse found that the interval from the diagnosis of
prolapse to delivery was significantly longer in infants with a poor
outcome than those with intact survival (median, 30 vs. 24
minutes).21 We would not reduce such CP cases unless
obstetric facilities throughout the country can provide immediate
cesarean delivery within 15 minutes. However, half of the deliveries are
managed in a private clinic where the emergency cesarean section is not
available.
Although electronic fetal monitoring (EFM) has not yet been shown to be
a good predictor of fetal asphyxia,22,23 previous
studies suggested that optimal intrapartum care could offer a preventive
opportunity of labor asphyxia in cases with normal admission FHR
tracings.24,25 Furthermore, a retrospective study
suggested the combination of EFM with clinical risk factors performed
better for screening CP than EFM alone.26 As a risk
screening of umbilical cord troubles before labor management, ultrasound
screening, triage of pregnant women according to risks of emergency
cesarean section, and appropriate intrapartum management of FHR combined
with evolution patterns are recommended.5,27,28 In
case these factors are recognized, the parturients should be placed
under continuous observation of FHR with preparing an emergency cesarean
section for early intervention to abnormal FHR that may cause fetal
brain damage.