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\begin{document}

\title{Predictors for histological chorioamnionitis among women with preterm
premature rupture of membranes after dexamethasone administration:a
retrospective study}



\author[1]{Jing Peng}%
\author[1]{Ying Chen}%
\author[1]{Sheng Wan}%
\author[2]{Tianfan Zhou}%
\author[3]{Yu-Sin Chang}%
\author[4]{Xiaobo Zhao}%
\author[5]{Xiaolin Hua}%
\affil[1]{Tongji University Shanghai First Maternal and Infant Hospital}%
\affil[2]{Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University}%
\affil[3]{Milwaukee School of Engineering}%
\affil[4]{1.	Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Shanghai Tongji University School of Medicine, Shanghai, China}%
\affil[5]{Shanghai Jiao Tong University School of Medicine, Xinhua Hospital}%


\vspace{-1em}



  
  \date{June 13, 2024}


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\selectlanguage{english}
\begin{abstract}
Objective: To investigate reliable biomarkers for predicting
histological chorioamnionitis (HCA). Design: In this retrospective
study, PPROM mothers were treated with a course of dexamethasone. Blood
tests for serum indictors were conducted continuously after first
injection. Setting: One Shanghai hospital Population: PPROM mothers
before 34 0/7 weeks of gestation Methods: Data were compared by General
Linear Model analysis. The diagnostic accuracy in predicting HCA were
evaluated with ROC curve. Main Outcome Measures: The response of
infectious indictors to dexamethasone treatment; the diagnostic accuracy
for CRP and PCT in predicting HCA. Results: We found 98 HCA women
(62.42\%) and 59 CON women (37.58\%) in 157 PPROM mothers. WBC and
neutrophil significantly increased 24 hours after the first injection in
both groups, followed by a decrease at 72 hours post first injection
(P\textless{}0.05). No significances were found between two groups in
WBC, neutrophil and lymphocyte. Both CRP and PCT were significantly
higher in the HCA group after first injection. PCT had both high
specificity and sensitivity, especially at the baseline (cutoff, 0.031
ng/ml). Furthermore, the positive predictive values (PPV) of PCT were
respectively 0.946 and 0.960 at 48 (cutoff, 0.049 ng/ml) and 72 (cutoff,
0.051 ng/ml) hours, which were better than the corresponding PPV of CRP.
Conclusion: The response of WBC, neutrophil and lymphocyte to
dexamethasone could be differentiated from uterine infection; PCT could
be a reliable biomarker for early diagnosis of HCA. Funding: Shanghai
Municipal Commission of Health and Family Planning (GWIV-26, 202040128);
Pudong Commission of Health and Family Planning (PW2019D-13).%
\end{abstract}%



\sloppy


\textbf{Predictors for histological chorioamnionitis among women with
preterm premature rupture of membranes after dexamethasone
administration:} \textbf{a retrospective study}

\textbf{Running title: HCA predictors among PPROM women after
dexamethasone administration}

Jing Peng\#, Department of Obstetrics and Gynecology, Shanghai First
Maternity and Infant Hospital, School of Medicine, Tongji University,
Shanghai 200092, China;Email:~penxiaoduo0725@163.com

Ying Chen\#, Department of Obstetrics and Gynecology, Shanghai First
Maternity and Infant Hospital, School of Medicine, Tongji University,
Shanghai 200092, China;Email:~chenyingi@51mch.com

Sheng Wan, Department of Obstetrics and Gynecology, Shanghai First
Maternity and Infant Hospital, School of Medicine, Tongji University,
Shanghai 200092, China;Email: shengwan991@163.com

Tianfan Zhou, Shanghai Key Laboratory of Maternal Fetal Medicine,
Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji
University, Shanghai 200092, China;Email: zhoueri\_9789@tongji.edu.cn

Yu-Sin Chang, Department of Mathematics, Milwaukee School of
Engineering, Milwaukee, WI 53202, USA;Email: ~changy@msoe.edu

Xiaobo Zhao*, Department of Obstetrics and Gynecology, Shanghai First
Maternity and Infant Hospital, School of Medicine, Tongji University,
Shanghai 200092, China;Email: zhaoxiaobo@51mch.com

Xiaolin Hua*, Department of Obstetrics and Gynecology, Shanghai First
Maternity and Infant Hospital, School of Medicine, Tongji University,
Shanghai 200092, China;Email: xiaolin\_hua@tongji.edu.cn

\textsuperscript{\#}Jing Peng and Ying Chen contributed equally to this
work.

corresponding author:

Xiaobo Zhao:

Telephone number: +86 18017211625; email address: zhaoxiaobo@51mch.com;

Xiaolin Hua:

Telephone number: +86 18930502621; email address:
xiaolin\_hua@tongji.edu.cn

\textbf{Objective:}

To investigate reliable biomarkers for predicting histological
chorioamnionitis (HCA).

\textbf{Design:}

In this retrospective study, PPROM mothers were treated with a course of
dexamethasone. Blood tests for serum indictors were conducted
continuously~after first injection.

\textbf{Setting:} One Shanghai hospital

\textbf{Population:} PPROM mothers before 34 0/7 weeks of gestation

\textbf{Methods:}

Data were compared by General Linear Model analysis. The diagnostic
accuracy in predicting HCA were evaluated with ROC curve.

\textbf{Main Outcome Measures:}

The response of infectious indictors to dexamethasone treatment; the
diagnostic accuracy for CRP and PCT in predicting HCA.

\textbf{Results:}

We found 98 HCA women (62.42\%) and 59 CON women (37.58\%) in 157 PPROM
mothers. WBC and neutrophil significantly increased 24 hours after the
first injection in both groups, followed by a decrease at 72 hours post
first injection (P\textless{}0.05). No significances were found between
two groups in WBC, neutrophil and lymphocyte. Both CRP and PCT were
significantly higher in the HCA group after first injection. PCT had
both high specificity and sensitivity, especially at the baseline
(cutoff, 0.031 ng/ml). Furthermore, the positive predictive values (PPV)
of PCT were respectively 0.946 and 0.960 at 48 (cutoff, 0.049 ng/ml) and
72 (cutoff, 0.051 ng/ml) hours, which were better than the corresponding
PPV of CRP.

\textbf{Conclusion:}

The response of WBC, neutrophil and lymphocyte to dexamethasone could be
differentiated from uterine infection; PCT could be a reliable biomarker
for early diagnosis of HCA.

\textbf{Funding:}

Shanghai Municipal Commission of Health and Family Planning (GWIV-26,
202040128); Pudong Commission of Health and Family Planning
(PW2019D-13).

\textbf{Keywords:}

Preterm premature rupture of membrane, histological chorioamnionitis,
dexamethasone, white blood cell count, C-reactive protein, procalcitonin

\textbf{Tweetable abstract:}

HCA might not influence the response of WBC, neutrophil and lymphocyte
in PPROM women within 72 hours after first injection; PCT could be a
sensitive and reliable marker for early diagnosis of HCA.

\textbf{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.

\textbf{Methods}

\textbf{Participants}

Patients with preterm premature rupture of membranes (PPROM) admitted
into our hospital between January 2019 and December~2021 were included
in this study. Inclusion criteria: all patients including single
pregnancy or multiple pregnancy met the diagnostic criteria of
spontaneous PPROM{[}18{]}, with gestational age between 26 0/7 and 33
6/7 weeks. After admission (baseline), all women received a single
course of four intramuscular injections of 6 mg dexamethasone at 12-hour
intervals to facilitate fetal lung maturity. A 7-day course of therapy
of latency antibiotics with a combination of intravenous ampicillin and
erythromycin for 48 hours followed by oral amoxicillin and erythromycin
was given. Tocolytic agent like nifedipine was cautiously administrated
for the first 48 hours if contractions were occurring and avoided if
there was evidence of infection. Magnesium sulfate treatment was
performed as a neuroprotective in pregnancies at less than 32 0/7 weeks
of gestation. Culture for group B streptococci (GBS) were performed for
all women.

Exclusion criteria: women with the complications of acute rheumatism,
other infections, substantial abnormalities in neurological,
psychiatric, cardiac, endocrinological, hematologic, hepatic, renal, or
metabolic functions as determined by history, physical examination and
blood screening tests were all excluded. Women who had an interval of
admission to delivery of more than 7 days or less than 3 days during
expectant management were also excluded. Prolongation of pregnancy was
associated with a higher risk of chorioamnionitis{[}18{]} while a 7-day
course of therapy of latency antibiotics is recommended during expectant
management as discussed in detail above, and a single course of
corticosteroids may persist 48 hours. Therefore, we excluded this
condition. The study protocol was approved by the hospital's ethics
committee (No. KS22218).

\textbf{Study design}

Before dexamethasone was injected, blood was drawn for peripheral WBC,
neutrophil, lymphocyte, CRP and PCT. Then the same tests were repeated
at 24, 48 and 72 hours after the injection of the first dose of
dexamethasone. Delivery was performed (induction or cesarean as
appropriate) after 34 0/7 weeks of gestation or after the development of
early signs of intraamniotic infection. All patients underwent placenta
pathologic examination after birth. HCA is diagnosed in the presence of
acute inflammatory changes in any of the tissue samples (amnion,
chorion-decidua, umbilical cord, and chorionic plate), using previously
published criteria{[}19{]}, which manifests as neutrophils in the
chorion or in the chorion and amnion on the examination of a membrane
roll and chorionic plate of the placenta. Two independent pathologists
reviewed the histology slides of the placentas for the pregnant women
participating in the study. Women confirmed HCA with the pathological
diagnosis of placenta were included into the HCA group while others into
the non-HCA (CON) group. CCA is diagnosed clinically in accordance with
the following signs: fever ([?]38\selectlanguage{ngerman}°C orally), vaginal discharge odor,
maternal tachycardia (\textgreater{}100 beats per minute), and fetal
tachycardia (\textgreater{}160 beats per minute), abdominal pain,
uterine tenderness, and leukocytosis. The presence of at least three of
these signs has been shown to indicate a strong probability of
chorioamnionitis{[}20{]}.

\textbf{Statistical analysis}

Comparisons between continuous variables were evaluated by the
Student's\emph{t} \selectlanguage{english}-test for independent samples, and proportions were
compared with the chi\selectlanguage{english}-squared test or the Fisher's exact test.
Comparisons between baseline and after\selectlanguage{english}-treatment periods were drawn by
Repeated Measures of General Linear Model analysis. Outcomes in the CON
group and the HCA group were analyzed by the multivariate~analysis. ROC
curve was used to calculate the cut-off, sensitivity, specificity,
positive predictive value, and negative predictive value of the optimal
cut-off value, respectively. All analyses were completed with SPSS
version 23 software. All tests for statistical significance were
two\selectlanguage{english}-tailed and were calculated under the assumption of a type I error
being smaller than 0.05 (p\textless{}0.05). Data are presented within
one standard deviation of mean.

\textbf{Results}

\textbf{Maternal and neonatal characteristics}

Initially, a total of 380 patients were enrolled in the study; 223 women
were removed from the study based on the exclusion criteria stated
above. A total of 157 mothers were involved in this study with 98 women
(62.42\%) detected HCA and 59 women (37.58\%) detected non-HCA
eventually. The number of patients who met each exclusion criterion is
shown in Figure 1. Demographic and clinical characteristics, and the
risk factors of the mothers are given in Table 1. Mothers with or
without HCA were not significantly different in comparison to age,
interval of admission to delivery, incidence of multiple pregnancy,
infertility, gestational diabetes mellitus, cesarean delivery rate,
culture of vaginal secretion including streptococcus agalactiae (GBS),
mycoplasma and candidiasis (p\textgreater{}0.05)). Three characteristics
have shown significant, which are gestational age at admission (weeks),
gestational age at delivery (weeks), and birth weight (grams). The mean
gestational age at admission for the CON group was 32.27 weeks with
standard deviation 1.31 weeks, but for the HCA group was 30.09 weeks
with standard deviation 1.94 weeks. Both showed very strong significance
as the p-value was smaller than 0.001. Interval of admission to delivery
did not show significance between two groups as the p-value is 0.31.
There were only two women meeting the criteria of CCA in the CON group
(3.4\%) and 7 women in the HCA group (7.1\%), which showed no
significant difference with the p-value 0.485. Infants of
non-chorioamnionitis mothers were significantly heavier than those of
mothers in the HCA with the p-value being smaller than 0.001.
Specifically, the mean of the CON (HCA) group was 2052 (1772) grams with
standard deviation 284 (317) grams, respectively. Apgar scores in two
groups were similar.

\textbf{The response of WBC to dexamethasone treatment}

In Fig. 2A, patients were divided into two groups according to the
histological chorioamnionitis. Both groups showed a similar significant
increase in mean WBC count. In Table 2, mean WBC count increased from
the baseline value of 9.36x10\textsuperscript{9} to
12.24x10\textsuperscript{9} cell/L by 30.77\% (p\textless{}0.001) in the
CON group, and from 9.71x10\textsuperscript{9} to
12.30x10\textsuperscript{9} cell/L by 26.67\% (p\textless{}0.001) in the
HCA group 24 hours after injection of the first dose of dexamethasone.
Then the level of mean WBC remained stable in both groups for the next
24 hours, before declining to 11.24x10\textsuperscript{9} cell/L in the
CON group and to 11.41x10\textsuperscript{9} cell/L in the HCA group 72
hours after the first injection, without returning to the baseline level
(p\textless{}0.001 in both groups). The overall analysis with repeated
measure ANOVA revealed no significant differences between two treatment
groups at all the time points. These results indicate the same
physiologic leukocytosis after dexamethasone treatment in both CON and
HCA groups.

\textbf{The response of neutrophil to dexamethasone treatment}

Similar to mean WBC count, in Fig. 2B and Table 2, significant rises in
mean neutrophil in both groups were noted 24 hours after injection of
the first treatment; there was a 44.85\% increase in the CON group from
7.18x10\textsuperscript{9} to 10.40x10\textsuperscript{9} cell/L
(p\textless{}0.001) and a 39.87\% increase in the HCA group from
7.45x10\textsuperscript{9} to 10.42x10\textsuperscript{9} cell/L
(p\textless{}0.001). Declining levels of neutrophil were recorded on day
three (72 hours) after the first dexamethasone injection compared to the
value at day two (48 hours). There was a 17.45\% decline in the CON
group from 10.37x10\textsuperscript{9} to 8.56x10\textsuperscript{9}
cell/L (p\textless{}0.001) and a 16.38\% decline in the HCA group from
10.44x10\textsuperscript{9} to 8.73x10\textsuperscript{9} cell/L
(p\textless{}0.001); these levels remained higher than in the baseline
(p\textless{}0.001 in both groups). At all the time points, no
significant difference in mean neutrophil between two groups was found
during the process. The above data confirmed HCA might not influence the
response of neutrophil to dexamethasone in PPROM women.

\textbf{The response of} l\textbf{ymphocyte to dexamethasone treatment}

24 hours after the initial treatment (Fig. 2C and Table 2), lymphocyte
in the CON group descended~significantly by 16.34\% (p\textless{}0.001);
lymphocyte in the HCA group also declined significantly by 16.78\%
(p\textless{}0.001). At 48 hours, mean lymphocyte levels in both groups
returned to their baseline levels. At 72 hours after first injection, a
significant increase in lymphocyte levels was recorded. Lymphocyte
levels went from 1.51x10\textsuperscript{9} to
1.91x10\textsuperscript{9} cell/L, an increase of 26.49\%
(p\textless{}0.001) in the CON group, and a similar elevation was found
from 1.42x10\textsuperscript{9} to 1.81x10\textsuperscript{9} cell/L, an
increase of 27.46\% (p\textless{}0.001) in the HCA group. There was no
significance in mean lymphocyte levels between the HCA and CON groups
during the process. These results demonstrate that both groups had
similar physiologic response to dexamethasone whether they had HCA or
not.

\textbf{The response of CRP to dexamethasone treatment}

CRP level changes were quite different between the CON and HCA groups
after the injection of dexamethasone (Fig. 2D and Table 2). In the CON
group, CRP levels began to decline significantly by 31.71\% from the
baseline of 1.64 to 1.12 mg/L at 48 hours after the initial treatment
(p=0.024) and went on to reach the lowest level of 1.06 mg/L at 72 hours
post initial treatment (by 35.37\%, p=0.045). In contrast, in the HCA
group, a significant increase in mean CRP levels of 58.82\% was found
from the baseline of 2.38 to 3.78 mg/L at 24 hours after treatment
(p=0.013) and the CRP levels steeply dropped to 2.81mg/L at 48 hours,
this level was similar to the baseline (p=0.403). When comparing the CRP
levels between the two groups, results showed significant difference at
24 hours (1.46 vs. 3.78 mg/L, p=0.018), 48 hours (1.12 vs. 2.81 mg/L,
p=0.018) and 72 hours (1.06 vs. 2.23 mg/L, p=0.001). The response of CRP
to dexamethasone injection might be more likely associated with HCA.

\textbf{The response of PCT to dexamethasone treatment}

PCT levels in the CON group (Fig. 2E and Table 2) increased from the
baseline value of 0.024 to 0.030 ng/ml (p\textless{}0.001) when measured
at 24 hours post injection, and then remained at the same level for the
next 48 hours. Similarly, PCT levels in the HCA group increased from
0.040 to 0.058 ng/ml (p=0.016) 24-hours after the injection of
dexamethasone. The difference was that PCT levels continued to increase
in the HCA group to a peak of 0.110 ng/ml at 72 hours (p=0.001).
Comparing the two groups, PCT levels in the HCA group were consistently
higher than those in the CON group 72 hours after the first injection
(p\textless{}0.05). These results indicate that HCA instead of
dexamethasone might influence the response of PCT in PPROM women less
than 34 gestational weeks. Due to this evidence, we analyzed the
diagnostic values of PCT and CRP in the next step of our research.

\textbf{The diagnostic values of PCT and CRP}

As shown in Figure. 3 and Table. 3, for women at baseline and different
times after their initial treatments (24, 48 and 72 hours), the areas
under ROC curves of CRP were 0.588, 0.788 ,0.701, and 0.714,
respectively, with statistically significant differences only in 24, 48
and 72 hours (p\textless{}0.001). As for PCT, the areas under ROC curves
of the same time point were 0.763, 0.730, 0.901, and 0.902,
respectively, with statistically significant differences in all the time
points (p\textless{}0.001). Meanwhile, the areas of PCT were
significantly better than those of CRP at baseline, 48 and 72 hours
after the first injection (p\textless{}0.05).

Using the optimal cutoff value as the positive threshold, the
sensitivities of CRP at baseline and different time after treatment (24,
48 and 72 hours) were 0.837, 0.918, 0.837, 0.786 and the specificities
were 0.373, 0.542, 0.542, 0.644, respectively. As for PCT, the
sensitivities at the same time were 0.765, 0.765, 0.796, and 0.816; the
specificities were 0.746, 0.678, 0.932, and 0.949, respectively.
Generally, CRP had high sensitivity but low specificity while PCT had
high specificity and modest sensitivity. It is worth noting that both
sensitivity and specificity of PCT were prominent initially at the
baseline (cutoff, 0.031ng/ml), not to mention 48 hours (cutoff, 0.048
ng/ml) and 72 hours (cutoff, 0.051 ng/ml), which indicated PCT might be
more sensitive for early diagnosis of HCA than CRP.

The positive predictive values (PPV) of PCT at the baseline and
different times after initial treatment (24, 48, and 72 hours) were
0.819, 0.781, 0.946, and 0.960, all of which were better than the
corresponding~negative predictive values (NPV) (0.679, 0.657, 0.753, and
0.775). In contrast, the PPV and NPV of CRP seemed to have no advantage
in comparison with those of PCT at the same time; the PPV of PCT were
especially prominent at 48 and 72 hours. These results demonstrated that
PCT might be a reliable candidate for HCA diagnosis.

\textbf{Discussion}

This study retrospectively analyzed 157 cases of PPROM women with
gestational age between 26 0/7 and 33 6/7 weeks and investigated the
dynamic responses of maternal WBC, neutrophil, lymphocyte, CRP and PCT
to antenatal dexamethasone. We found both CON and HCA groups had similar
physiologic response to dexamethasone in WBC, neutrophil, and lymphocyte
whether they had HCA or not. On the contrary, HCA might influence the
response of CRP and PCT in PPROM women, and notably PCT had better
predictive values of HCA when compared with those of CRP.

Membrane rupture may occur for a variety of reasons and intraamniotic
infection has been shown to be commonly associated with preterm PROM,
especially at earlier gestational ages{[}6, 21{]}. Previous studies
which have shown HCA occurred in approximately 50--60\% of women with
PPROM{[}22, 23{]}. Consistent with those data, a total of 157 mothers
were involved in this study and 98 women (62.42\%) were identified as
HCA. Only 5 patients (5.75\%) presenting positive symptoms were
diagnosed with CCA, of whom 4 were proven to have HCA, which suggests
that diagnosis of CA solely based on clinical manifestation may
underestimate the true risks to the offspring. Hence, it is vital for
detection of HCA in PPROM women, especially in those with younger
gestational ages who were more prone to greater incidence of HCA{[}6{]}.
Furthermore, limitations on the timeliness of placenta pathological
examination urges the value of early diagnosis of HCA that may help
provide timely intervention to newborn infants.

Antenatal corticosteroid therapy has shown a transient physiologic
response including an increase in maternal WBC and neutrophil, which is
caused by increasing leukocyte extravasation from bone marrow and
decreasing their clearance from blood vessels{[}11-13{]}. Some study
demonstrated WBC increased from a baseline value of
11.3x10\textsuperscript{9} to 16.2x10\textsuperscript{9} cell/L 24 hours
after treatment and normalized thereafter{[}24{]}. Voon et al. found
mean WBC in a preterm subgroup was initially
10.65x10\textsuperscript{9}cell/L, then rose to
11.99x10\textsuperscript{9} cell/L at 36 hours after dexamethasone
injection, and finally returned to baseline level{[}13{]}. Our study
confirmed the physiologic leukocytosis after administration of
dexamethasone in PPROM which could differentiate from uterine infection.
In comparison, mean WBC and neutrophil counts in our study did not
return to their initial baseline levels even at 72 hours after
treatment, which is different from the aforementioned studies. This may
be explained by the fact that the preterm women recruited by prior
studies included both PPROM patients and those with intact membranes,
while women in our study only included PPROM mothers. The results
indicate the responses of maternal WBC and neutrophil in the first 72
hours after dexamethasone injection might not be influenced by HCA;
hence they could not predict HCA in PPROM women.

Different from WBC, neutrophil and lymphocyte, CRP and PCT levels in the
HCA group were consistently higher than those in the CON group at
different time points after patients received their first injection,
indicating the responses of CRP and PCT to dexamethasone injection might
be associated with HCA. When it comes to analysis of diagnostic value,
this study showed that PCT is better than that of CRP for early
prediction of HCA. The areas under ROC curves of PCT were significantly
better than those of CRP at baseline, 48 and 72 hours, which indicate
that PCT had greater predictive value than CRP. Similarly, some scholars
found that both CRP and PCT had satisfactory accuracy, and the
diagnostic value of PCT is better than CRP for women pregnant for 28-34
weeks{[}17{]}. PCT also had both high specificity and sensitivity even
at the initial baseline, whereas CRP had high sensitivity but low
specificity, which meant PCT might be more sensitive for early diagnosis
of HCA than CRP. A previous study found PCT inversely had a poor
sensitivity and a modest specificity compared with CRP{[}15{]}, but the
author included all the intrauterine infectious patients without
distinction between~CCA and HCA. In the HCA group, mean CRP showed a
significant rise only at 24 hours after initial treatment before
dropping to the baseline vale where it remained stable. PCT levels
increased~continually from baseline to the peak at 72 hours post first
treatment, which reflected the dynamic response of CRP and PCT after
dexamethasone and required constantly monitoring of trends.

\textbf{Conclusion}

Our results confirmed HCA might not influence the response of WBC,
neutrophil, and lymphocyte in PPROM women before 34 0/7 gestational
weeks within 72 hours after first injection, which could be
differentiated from uterine infection. Moreover, PCT could be a
sensitive and reliable biomarker for early diagnosis of HCA.

\textbf{Acknowledgements}

This study was funded by the Shanghai Municipal Commission of Health and
Family Planning (GWIV-26, 202040128) and Pudong Commission of Health and
Family Planning (PW2019D-13).

\textbf{Declaration of Competing Interest}

The authors report no declarations of interest.

\textbf{Author Roles}

Jing Peng: study design, data analysis, interpretation and manuscript
writing

Ying Chen: study design, data abstraction and manuscript writing

Sheng Wan: data acquisition and interpretation

Tianfan Zhou: data acquisition, data interpretation and manuscript
revision

Yu-Sin Chang: critical manuscript revision

Xiaobo Zhao: study design, data interpretation and manuscript revision

Xiaolin Hua: study design, data analysis, data interpretation and
manuscript revision

\textbf{Ethics approval}

The study protocol was approved by the hospital's ethics committee (No.
KS22218).

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\textbf{Legend:}

Fig. 1. Flowchart and study design

Fig. 2: The response of different infectious indicators to dexamethasone
in PPROM women

A and B: WBC and neutrophil increased 24 hours after the first injection
in both groups, followed by a decrease at 72 hours post first injection
to levels that remained higher than the baseline. No significance was
found between two groups. C: Mean lymphocyte declined at 24 hours
whereas peaked ultimately at 72 hours. There was no significance between
the two groups. D and E: In the HCA groups, CRP temporarily increased at
24 hours before dropping to the baseline and remaining at stable level;
PCT increased~continually to the peak at 72 hours. Both CRP and PCT were
significantly higher in HCA group after first injection.

Fig. 3: The ROC curves of CRP and PCT for HCA after administration of
dexamethasone

A: For women at baseline, the area under ROC curve of PCT was
significantly better than that of CRP (0.763 vs. 0.588;
p\textless{}0.05). B: The areas under ROC curve of CRP and PCT were
0.788 and 0.730, respectively. No significance was found between them.
C: The area under ROC curve of PCT was significantly better than that of
CRP at 48 hours (0.901 vs. 0.701; p\textless{}0.05). D: The area under
ROC curve of PCT was significantly better than that of CRP at 48 hours
(0.902 vs. 0.714; p\textless{}0.05).

Table. 1: Characteristics of PPROM women in CON and HCA group

Table. 2: Laboratory tests at baseline and after administration of
dexamethasone

Table. 3: The predictive analysis for CRP and PCT for HCA after
administration of dexamethasone\selectlanguage{english}
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