Introduction
A high proportion of preterm premature rupture of membranes (PPROM)
occurring before 34 weeks of gestation are associated with
chorioamnionitis (CA), which is caused primarily by the ascending
bacterial invasion of the vagina, leading to infection of fetal
membranes, placenta, amniotic fluid, and uterine cavity[1-3].
Chorioamnionitis could be divided into clinical CA (CCA) and
histological CA (HCA). CCA is diagnosed based on the presence of
clinical evidence before or during labor and delivery; HCA is identified
from the evidence of infection and inflammation in the examination of
the placenta[4, 5], with its clinical course often asymptomatic and
its prevalence higher than CCA[6, 7]. In addition, HCA was
associated with early-onset sepsis and combined perinatal comorbidities
in infants, which are of more diagnostic importance than CCA
alone[8]. However, confirmation of HCA through pathological
examination of the placenta is unable to provide an early warning for
the treatment of newborns. Therefore, it is vitally important to explore
a sensitive and accurate diagnostic biomarker for early detection of
histological chorioamnionitis that may allow for early intervention and
treatment of newborn infants.
As is well known, monitoring of maternal serum infectious indicators
including WBC, neutrophil, lymphocyte, CRP and PCT levels may assist in
early diagnosis of infection. However, antenatal corticosteroid therapy,
including either betamethasone or dexamethasone for women in preterm
labor[9, 10] have shown a transient increase in maternal WBC and
neutrophil, which is easily confused with chorioamnionitis and induces
unnecessary early termination of the pregnancy[11-13]. Although some
studies have shown that this increase was physiologic leukocytosis after
corticosteroid administration, most of those results were merely
obtained from PPROM patients without chorioamnionitis, lacking the
comparison of data from a HCA group. In addition, procalcitonin (PCT),
secreted by thyroid C-cells, is markedly elevated in many bacterial
infections and can be used as a prognostic infectious indicator of
sepsis[14]. However, its role as a biomarker for the detection of
HCA in PPROM is still controversial[15-17]. Furthermore, the
constant response of PCT after injection of corticosteroids has not been
fully investigated.
Consequently, this retrospective study was conducted to thoroughly
investigate the dynamic responses of maternal WBC,
neutrophil, lymphocyte, CRP and PCT to antenatal dexamethasone in PPROM
women, compare the differences of
the above serum indicators between the CON women and HCA group, and
determine the predictive value of
CRP and PCT for predicting HCA by analyzing dynamical changes
constantly.