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\begin{document}

\title{Added prognostic value of longitudinal changes of angiogenic factors in
early-onset severe preeclampsia: analysis of maternal outcomes.}



\author[1]{Anna Peguero}%
\author[1]{Lorena Fernandez-Blanco}%
\author[2]{Edurne Mazarico}%
\author[1]{Leticia Benitez}%
\author[2]{Alba Gonzalez}%
\author[1]{Lina Youssef}%
\author[1]{Fatima Crispi}%
\author[1]{Sandra Hernández}%
\author[3]{Francesc Figueras}%
\affil[1]{Hospital Clinic de Barcelona Institut Clinic de Ginecologia Obstetricia i Neonatologia}%
\affil[2]{Hospital Sant Joan de Deu}%
\affil[3]{Hospital Clinic de Barcelona}%


\vspace{-1em}



  
  \date{May 26, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Background: Maternal levels of angiogenic factors are promising
prognostic parameters in patients with suspected preeclampsia, but in
women with confirmed preeclampsia this performance has been less
explored. Objective: To assess in women with early-onset severe
preeclampsia whether longitudinal changes in angiogenic factors improve
the prediction of adverse outcome. Study design: A cohort was created of
consecutive women admitted for early-onset severe preeclampsia with no
indication for immediate delivery. Levels of placental growth factor
{[}PlGF{]}, soluble fms-like tyrosine kinase {[}sFlt-1{]} and
sFlt-1/PlGF ratio were measured at admission and before delivery; and
average daily change was calculated. The association of longitudinal
changes of angiogenic factors with maternal complications and with the
time interval to delivery was evaluated by logistic and Cox regression.
Results: Sixty-three women were analyzed, of which 23 (36.5\%) had a
complication. Longitudinal changes of sFlt-1 were more pronounce in
complicated pregnancies (median: 1079.5 vs. 343.7 pg/mL/day; p=0.04). On
the multivariate analysis, the baseline model (clinical risk score and
sFlt-1 at admission) explained a 6.6\% of the uncertainty for
complication (R2-Naegelkerke). The addition of sFlt-1 longitudinal
changes improved this performance to 23.2\% (p=0.004). The median time
from admission to delivery was 3 days (95\% confidence interval:
1.9-4.05) in those in the highest quartile of sFlt-1 longitudinal
changes vs. 10 days (95\% confidence interval: 8.1-11.9) in the
remaining women (Log-rank test p\textless{}0.001). Conclusions:
Longitudinal changes in sFlt-1 maternal levels from admission for
confirmed early-onset severe preeclampsia add to baseline
characteristics in the prediction of maternal complications.%
\end{abstract}%



\sloppy


\textbf{INTRODUCTION}

Preeclampsia (PE) is a severe multisystem condition characterized by
hypertension and end-organ dysfunction. It complicates 2-8\% of
pregnancies (1) and is a leading cause of maternal and neonatal
morbidity and mortality (2,3).

We can distinguish two entities in terms of pathophysiology, in one hand
late-onset PE (developed after 34 weeks' gestation) and in the other
hand early-onset PE that is thought to be more related to placental
insufficiency (4--6), which confers higher maternal and neonatal risks
(3,7,8).

Expectant management improves neonatal outcome in selected cases of
early-onset PE (9,10). Thus, clinical decisions are determined by a
trade-off between reducing the risks of maternal complications by timely
delivery and minimizing the risks of prematurity by expectant
management. Therefore, a reliable prediction of maternal complications
is essential in selecting women for expectant management. So far, even
when multi-parametric risk-scoring is used, such prediction capacity is
still moderate (11,12).

Maternal levels of angiogenic factors at admission for suspected PE have
emerged as prognostic predictors, including placental growth factor
{[}PlGF{]}, soluble fms-like tyrosine kinase 1 {[}sFlt-1{]} and the
sFlt-1/PlGF ratio. These factors have showed a good capacity in ruling
out maternal complications and a moderate capacity in predicting its
occurrence (13,14). In addition, they may predict the interval to
delivery in suspected PE (15). It has been also suggested that
longitudinal changes of the angiogenic factors levels may provide
additional prediction capacity for the occurrence of complications in
suspected PE (16). The performance of this capacity in women with
confirmed PE has been less explored. Sequential angiogenic factors
differences has been compared retrospectively between early and
late-onset PE (17) or described prospectively in women admitted with
mixed hypertensive disorders (18). However, the clinical value of the
angiogenic factors longitudinal changes has not been specifically
investigated in early-onset cases already meeting severity criteria,
which is the clinical presentation with the greatest risk of maternal
and fetal complications (19).

The objective of this study is to test in early-onset severe PE whether
the longitudinal changes in maternal anigiogenic factors levels improve
the prediction capacity of adverse outcome and time interval to
delivery.



\textbf{MATERIALS AND METHODS}

\emph{Population}

Between March 2017 and April 2019 a prospective cohort was created of
consecutive singleton pregnancies with early-onset severe PE who were
admitted to the Departments of Maternal-Fetal Medicine at BCNatal
(Barcelona, Spain), comprising two referral university hospitals
(Hospital Cl\selectlanguage{ngerman}ínic and Hospital Sant Joan de Déu). Additional inclusion
criteria were the absence of maternal complications at admission (as
detailed below) and the absence of fetal indication for imminent
delivery. The study protocol was approved by the Ethics Committee
(HCB/2017/0077) and participants provided their written informed
consent.

\emph{Definitions}

PE was defined by the presence of de novo hypertension (systolic blood
pressure (BP) \emph{\textgreater{}} 140 mmHg and/or diastolic
BP\emph{\textgreater{}} 90 mmHg measured on two occasions at least 4
hours apart) after 20 weeks of gestation accompanied by proteinuria
(\emph{\textgreater{}} 300 mg/24h or a urine protein/creatinine ratio
\textgreater{} 0.3 mg/mmol)(20). Early-onset cases were considered when
admission occurred before 34 weeks of gestation. Gestational age was
calculated according to the crown-rump length at first-trimester
ultrasound scan (21). Severe features were defined according the
American College of Obstetricians and Gynecologists as: systolic
BP\emph{\textgreater{}} 160 mmHg or diastolic BP \emph{\textgreater{}}
110 mmHg on two occasions at least 4 hours apart, thrombocytopenia
(\textless{}100x10\textsuperscript{9}/L platelets), impaired liver
function (blood concentrations of liver enzymes to twice normal and/or
severe persistent right upper quadrant or epigastric pain unresponsive
to medication and not accounted for by alternative diagnoses), renal
insufficiency (serum creatinine concentration greater than 1.1 mg/dl in
absence of other renal disease), pulmonary edema or new-onset cerebral
or visual disturbances (22).

At admission, the risk for complications was estimated according to the
Prediction of complications in Early-onset-Preeclampsia (PREP-L) score
(12,23), which includes maternal age, gestational age, preexisting
medical conditions, protein-to-creatinine ratio, serum urea
concentration, platelet count, systolic blood pressure, need for
antihypertensive treatment or magnesium sulphate.

Maternal complications were defined as: (i) HELLP syndrome (lactate
dehydrogenase {[}LDH{]} \textgreater{}600 IU/L, AST to twice normal
values and platelet count \textless{}100x10\textsuperscript{9}/L); (ii)
Central nervous system dysfunction (eclampsia, Glasgow Coma Score
\textless{}13 (24), stroke, reversible ischemic neurological deficit or
cortical blindness); (iii) hepatic dysfunction (INR \textgreater{}1.2 in
the absence of disseminated intravascular coagulation, MELD
score\emph{\textgreater{}} 10 (25,26) or hepatic hematoma or rupture);
(iv) renal dysfunction (dialysis, serum creatinine concentration greater
than 150 \selectlanguage{greek}µ\selectlanguage{english}mol/L or urine output \textless{}0.5 ml/kg/h during 12 hours,
according to renal insufficiency by RIFLE criteria (27); or need for
treatment with furosemide to maintain urine output
\textgreater{}0.5ml/kg/h for 3 hours); (v) respiratory dysfunction
(pulmonary edema, requirement of invasive or non-invasive mechanical
ventilation, oxygen requirement greater than 50\% concentration for
longer than 1 hour or severe breathing difficulty {[}no criteria of
pulmonary edema but presence of dyspnea, crackles in pulmonary
auscultation and SaO\textsubscript{2}\textless{}90\%{]}); and/or (vi)
cardiovascular dysfunction (need for inotropic support, left ventricle
failure or myocardial infarction); (vii) critical hypertension
(requirement for three or more different antihypertensive treatments to
control BP).

Fetal growth restriction (FGR) was defined according to the Delphi
consensus for early-onset form (28).

\emph{Management}

At admission, all women underwent a physical and biochemical examination
according to standard recommendations. Maternal BP was monitored
continuously and laboratory tests were assessed at least once daily.
Magnesium sulfate for seizure prophylaxis and corticosteroid therapy for
fetal lung maturity were administered to all women. Antihypertensive
treatment was administered when BP was persistently 160/110 mmHg or
higher. Fetal assessment was performed by cardiotocograhy every day and
Doppler at least twice a week.

Indications for delivery were uncontrollable BP, maternal complications
(defined above), placental abruption or non-reassuring cardiotocographic
reading (29). Beyond 26 weeks, indications for delivery also included
persistent (\textgreater{}6 hours apart) ductus venosus (DV) Doppler
with reversed diastolic flow; and beyond 30 weeks persistent
(\textgreater{}6 hours apart) umbilical artery (UA) Doppler with
reversed end-diastolic flow or DV pulsatility index above the
95\textsuperscript{th} centile for gestational age (30). Elective
delivery was performed beyond 34 weeks after completion of pulmonary
maturation. Clinicians and researchers were unaware of the angiogenic
factor levels as they were measured after delivery on stored samples.

\emph{Samples collection and angiogenic factors measurement}

At admission and before delivery (within 12 hours), a 5 ml peripheral
maternal blood sample was obtained. Serum was separated by
centrifugation at 2000 g for 10 min at room temperature, and samples
were immediately stored at -80\selectlanguage{ngerman}ºC until assayed at an independent
laboratory.

Maternal serum concentrations of sFlt-1 and PlGF were determined by the
fully automated Elecsys assays for sFlt-1 and PlGF on an
electrochemiluminescence immunoassay platform (Cobas analyzers, Roche
Diagnostics). In all the kits, the intra-assay precision was
\textless{}4\% for both assays and the inter-assay precision was
2.3-5.6\% and 2.4-4.6\% for sFlt-1 and PlGF assays respectively.

Longitudinal changes were quantified by calculating delta values: (level
at delivery - levels at admission)/days from admission to delivery.

\emph{Sample size and statistical analysis}

From a previous cohort of women with severe early PE (31) we estimated
the interval from admission to delivery to be 12 days in non-complicated
and 5 days in complicated pregnancies. Assuming this difference between
women in the highest quartile of angiogenic delta values and those in
the 1\textsuperscript{st}-3\textsuperscript{rd} quartiles, for an
alpha-risk of 5\% and a power of 80\%, 56 women would be needed
(log-rank test)(32).

Variables were checked for normal distribution by Kolmogorov-Smirnov
test. Paired comparisons of the angiogenic values between admission and
delivery were performed by non-parametric Wilcoxon sign test.
Comparisons between uncomplicated and complicated pregnancies were
performed by Student-T (assuming unequal variances), Mann-Whitney U,
Pearson Chi-squared and Fisher-F, as appropriate.

The likelihood of maternal complications was modelled by logistic
regression (with robust estimation of the standard errors). Levels of
angiogenic factors were log-transformed. The predictive performance was
determined by receiver--operating characteristic (ROC) curve analysis.

The interval from admission to delivery was graphed by Kaplan-Meier
procedure and tested for differences in the survival time by the
angiogenic delta values quartile using Log Rank (Mantel-Cox) test. The
interval to delivery was modelled by multivariate Cox regression
checking for the assumptions of proportionality and log-linear
relationship.

Statistical analyses and graph constructions were performed using STATA
13.0 (StataCorp LT, Texas, USA) and R 3.1.2 (The R Foundation for
Statistical Computing) {[}package ``pROC''{]}.

\textbf{RESULTS}

During the study period 86 women were admitted for early-onset severe
PE. 68 of them had no maternal complications at admission and no fetal
indication for imminent delivery. Blood samples for angiogenic factors
measurement were not collected from 4 of these patients due to a breach
of the study protocol. In one additional case, blood sample was not
obtained at delivery. Thus, a total of 63 women were available for
analysis with both at-admission and at-delivery measurements. Out of
them, 23 patients (36.5\%) had a complication. Table 1 shows the
baseline characteristics by the presence of complications and
supplementary table 1 details the maternal complications. The median
time interval between admission and delivery was 9 days (ranging from 2
to 24). It was shorter in complicated pregnancies {[}7 (2-22){]} vs
{[}10 (2-24){]} in those without complications.

Supplementary table 2 shows the levels of the angiogenic factors at
admission and at delivery, with the delta values (expressing average
daily change). Of note, all the evaluated angiogenic factors
significantly differed between admission and delivery. Table 2 and
supplementary figure 1 depict the angiogenic factors levels in
uncomplicated and complicated pregnancies. Only the sFlt-1 delta values
were significantly different between those without and with complication
(median values: 343.7 vs. 1079.5 pg/mL/day; p=0.04). Expressed as
relative changes from the admission values, this corresponds to 2.6\%
vs. 8.2\% daily increase. Supplementary figure 2 shows the individual
and averaged changes of sFlt-1 by the occurrence of complications.

On the multivariate analysis, the baseline model (PREP-L risk score and
sFlt-1 at admission) explained 6.6\% of the uncertainty of complications
occurrence (R\textsuperscript{2} Naegelkerke). The addition of sFlt-1
delta values significantly improved this performance
(R\textsuperscript{2} Naegelkerke of 23.2\%; p=0.004). Table 3 shows the
logistic regression model which includes all three predictors. While the
area under the curve of the baseline model was 0.6 (95\%CI 0.46-0.75),
it increased to 0.75 (95\% CI 0.62-0.87) when the sFlt-1 delta was
added. For a 20\%, 30\% and 40\% of false-positive rates, detection
rates were better for the model including sFlt-1 delta: 57.1\% vs.
33.3\%; 66.7\% vs. 38.1\%; and 76.2\% vs. 47.6\%, respectively. Figure 1
shows both ROC curves.

Figure 2 shows the Kaplan-Meier graph of the time interval to delivery:
the median time was 3 days (95\%CI 1.96-4.05) in those in the highest
quartile of delta sFlt-1 values vs. 10 (95\%CI 8.1-11.9) in those in the
1\textsuperscript{st}-3\textsuperscript{rd} quartiles {[}Log Rank
(Mantel-Cox) p\textless{}0.001{]}.

Table 3 shows the Cox regression modelling of the time interval from
admission to delivery. Of note, to meet the proportional hazards
assumption, log-transformed sFlt-1 delta values had to be categorized in
quartiles and entered in the model as binary (highest quartile vs. those
the 1\textsuperscript{st}-3\textsuperscript{rd} quartile): hazard ratio
of 3.15 (95\%CI 1.67-5.86; p\textless{}0.001).

\textbf{DISCUSSION}

Our findings demonstrate that the longitudinal changes in sFlt-1 levels
from admission for early-onset severe PE improve the prediction of
maternal complications and the interval to delivery over baseline
clinical and analytical parameters.

Several previous studies have showed the ability of angiogenic factors
when cross-sectionally measured at admission for suspected PE in
stratifying the risk of adverse outcome, and demonstrated that abnormal
values were associated with a shorter duration to delivery (14,15,33).
The angiogenic factors changes during pregnancy are also well known
(34--36). In light of this evidence, it is reasonable to assume that the
change of the angiogenic factors levels over time may add further
predicting capacity for adverse outcome. Indeed, Zeisler et al (37)
found that in patients with suspected PE there was a greater
longitudinal increase in the sFlt-1/PlGF ratio in women who developed PE
and adverse maternal outcome than in those who did not develop it.
Additionally, Schoofs et al (16) suggested that repeated measurements of
the sFlt-1/PlGF ratio seem to be superior in predicting PE and its
complications to a single measurement.

All this evidence, however, come from studies in women with suspected PE
and whether these findings apply to women with diagnosed PE was unclear,
especially in early-onset severe PE. A retrospective study including 34
patients with diagnosed PE demonstrated that early-onset cases had a
higher daily increase in sFlt-1 (11\% vs. 3\%) and sFlt-1/PlGF ratio
(23\% vs. 8\%) compared to late-onset PE (17). More recently, Baltajian
et al (18) reported in a prospective cohort of 99 women with suspected
PE (53 of them confirmed) admitted before 37 weeks that daily changes of
sFlt-1 and sFlt-1/PlGF ratio were significantly higher in women ending
up having a maternal or fetal adverse outcome. This study could be
criticized because many of the described complications like FGR and
transaminitis were likely already present at admission. Thus, rather
than assessing the role of the angiogenic factors longitudinal changes
in predicting complications, this study may have addressed the
association of these changes with features of severe PE. Our results
strengthen the findings from previous studies and demonstrate the
clinical value of the angiogenic factors longitudinal changes even in
confirmed early-onset severe PE.

Interestingly, we found sFlt-1 more strongly associated with maternal
complications than PlGF. Consistently with our findings, the series by
Baltajian et al (18), that included women admitted for PE suspicion,
found that the median daily increase of sFlt-1 was 6 times higher in
women with adverse outcome, while no significant difference were found
in daily decrease of PlGF between women with and without adverse
outcome. In PE,~maternal sFlt-1 levels drop after~delivery to
\textless{}\selectlanguage{english} 1\% of its~pre-delivery value while PlGF drops to 30\% (36),
suggesting that sFlt-1 is almost uniquely produced by the placenta while
PlGF have other sources. Indeed, PlGF is expressed in a variety of
organs , tissues and cells (38). As the stressed endothelium produces
PlGF (39), this may be a compensatory mechanism to keep minimum levels
of circulating PlGF. Thus, one may speculate that being more closely
correlated with placental disease, sFlt-1 is a better marker of PE
severity than PlGF. The increased sFlt-1 values may trigger the
endothelial dysfunction that leads to PE complications (40).

Most guidelines recommend expectant management in selected cases of PE
until 34 weeks (41), based on the evidence that the risk of serious
complications is low when appropriate care is provided and on the
derived neonatal benefits (9,10,42). However, the selection of cases at
especially high-risk for maternal complications is clinically
challenging. All guidelines recommend a similar set of severity criteria
(41), that were established from experts opinion without a good evidence
on their individual performance in predicting complications. In
addition, except for the Canadian guideline (43), gestational age at
diagnosis was not included as a severity criteria, while there is good
evidence on its independent contribution in predicting maternal
morbidity (44). A step forward was made by the PRE-EMPT consortium
developing and validating a scoring tool for risk-stratification of
women admitted with PE (the PIERS score), with good capacity and
predictive performance (11). However, this model included women with any
onset PE, and not specifically those with early-onset. More recently,
the PREP-L model was specifically derived for early-onset PE. Compared
to the PIERS model, which had an AUC between 0.7-0.8 at one week after
admission, the PREP-L model showed discrimination of 0.82 for a longer
period until postnatal discharge from hospital (12). Our study shows
that the addition of sFlt-1 delta values may increase the prediction of
maternal complications achieved by PREP-L and sFlt-1 at admission. If
confirmed, our results would enable the use of longitudinal changes in
angiogenic factors as a stratifying tool to stablish time of delivery.

Our series has some unique features. It is a prospective cohort of women
admitted for confirmed early-onset severe PE. The angiogenic factors
were longitudinally measured and evaluated for the prediction of
incident complications. In addition, managing clinicians were blinded to
these measurements. We also acknowledge some limitations. First, the
relatively small sample size which does not allow the evaluation of
individual complications. However, this sample size has to be regarded
in the context of the very low incidence of early-onset PE
(\textasciitilde{}0.5\%), which is even lower if we consider severe
cases without complications at admission (7). Thus, 63 cases correspond
to a base population of more than 15,000 deliveries. Second, we only
measured the angiogenic factors at two time points, and, therefore,
other non-linear trends could not be explored. In particular, whether
the rise in sFlt-1 precedes the onset of the complication could not be
assessed in our study. Finally, our findings do not necessarily mean
that modifying the clinical management according to longitudinal changes
in sFlt-1 would improve the maternal outcomes.

\textbf{CONCLUSION}

In summary, our study suggests that longitudinal changes in maternal
sFlt-1 levels from admission for confirmed PE add to baseline
characteristics in predicting maternal complications and interval to
delivery. Further studies are needed to evaluate the evolution of
angiogenic factors levels at fixed time points after admission and to
address the impact of incorporating this parameter in the clinical
management of early-onset PE on maternal and fetal outcomes.



\textbf{ACKNOWLEDGMENTS}

We are indebted to the IDIBAPS Biobank and ``Biobanc de l'Hospital
Infantil Sant Joan de Deu per a la Investigacio'', integrated in the
Spanish National Biobank Network of ISCIII, for the sample and data
procurement.

\textbf{DISCLOSURE OF INTERESTS}

The authors report no conflict of interest.

\textbf{CONTRIBUTION TO AUTHORSHIP}

AP, EM, and FF: study design. AP, LFB, EM, and SH: patient recruitment.
LFB, LB, and AG: data collection. AP and FF: data analysis. AP, LFB, EM,
LB, AG, LY, FC, SH, and FF: drafting the manuscript and critical
revision. All the authors have seen and approved the final version of
the article.

\textbf{DETAILS OF ETHICS APPROVAL}

This study was approved on 22 March 2017 by the Institutional Ethics
Committee of Hospital Clinic de Barcelona (Reference number:
HCB/2017/0077).

\textbf{FUNDING}

None.

All authors have seen and approved the \selectlanguage{english}final ver-

sion of the article

All authors have seen and approved the \selectlanguage{english}final ver-

sion of the article

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\textbf{Table 1.} Baseline characteristics by the subsequent occurrence
of complications\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
& uncomplicated preeclampsia (n=40) & complicated preeclampsia (n=23) &
p value\tabularnewline
\midrule
\endhead
Demographic characteristics & Demographic characteristics & Demographic
characteristics & Demographic characteristics\tabularnewline
Maternal age (years) (Mean{[}SD{]}) & 32.6 (5.6) & 35.3 (6.1) &
0.09\tabularnewline
Non-Hispanic white (n{[}\%{]}) & 18 (45) & 8 (34.8) &
0.43\tabularnewline
Smoking (n{[}\%{]}) & 5 (12.5) & 2(8.7) &
1\textsuperscript{*}\tabularnewline
Obesity (BMI \emph{\textgreater{}}30) (n{[}\%{]}) & 6 (15) & 2 (8.7) &
0.7\textsuperscript{*}\tabularnewline
Nulliparity (n{[}\%{]}) & 28 (70) & 14(60.9) & 0.46\tabularnewline
Preeclampsia history (n{[}\%{]}) & 3 (7.5) & 4(17.4) &
0.25\textsuperscript{*}\tabularnewline
FGR history (n{[}\%{]}) & 3 (7.5) & 0 &
0.29\textsuperscript{*}\tabularnewline
Chronic hypertension (n{[}\%{]}) & 6 (15) & 3 (13) &
1\textsuperscript{*}\tabularnewline
Renal disease (n{[}\%{]}) & 2 (5) & 1 (4.3) &
1\textsuperscript{*}\tabularnewline
Diabetes (n{[}\%{]}) & 2 (5) & 0 &
0.53\textsuperscript{*}\tabularnewline
Maternal characteristics at admission & Maternal characteristics at
admission & Maternal characteristics at admission & Maternal
characteristics at admission\tabularnewline
GA at admission (weeks) (Mean{[}SD{]}) & 30.3 (2.9) & 29.7 (2.8) &
0.4\tabularnewline
Systolic blood pressure (mmHg) (Mean{[}SD{]}) & 168 (16) & 167(15) &
0.78\tabularnewline
Diastolic blood pressure (mmHg) (Mean{[}SD{]}) & 104 (8.5) & 101 (7.8) &
0.22\tabularnewline
Proteinuria (mg/24h) (Median{[}IQR{]}) & 1375 (3107) & 2564 (4791) &
0.18\textsuperscript{*}\tabularnewline
Platelet count (x10\textsuperscript{9} L) (Mean{[}SD{]}) & 216 (78.6) &
172 (64.2) & 0.02\tabularnewline
Creatinine (\selectlanguage{greek}µ\selectlanguage{english}mol/L) (Mean{[}SD{]}) & 61.2 (14.3) & 64.8 (21.1) &
0.47\tabularnewline
Aspartate transaminase IU/L, (Median{[}IQR{]}) & 22 (31) & 26 (25) &
0.87\textsuperscript{*}\tabularnewline
Oxygen saturation (\%)(Median{[}IQR{]}) & 98.5(2) & 97.5(2) &
0.51\textsuperscript{*}\tabularnewline
PREP-L risk score (Mean{[}SD{]}) & 73.4 (18.6) & 80.3 (10) &
0.07\tabularnewline
Perinatal characteristics & & &\tabularnewline
GA at delivery (weeks) (Mean{[}SD{]}) & 31.7 (2.5) & 31.1 (2.3) &
0.29\tabularnewline
Birthweight (g) (Mean{[}SD{]}) & 1252 (458) & 1286(437) &
0.77\tabularnewline
FGR (n{[}\%{]}) & 34 (85) & 18 (78.3) &
0.51\textsuperscript{*}\tabularnewline
Cesarean section (n{[}\%{]}) & 34 (85) & 22 (95.7) &
0.41\textsuperscript{*}\tabularnewline
5-min Apgar\emph{\textless{}}7 (n{[}\%{]})\textsuperscript{+} & 5 (13.2)
& 4(17.4) & 0.72\textsuperscript{*}\tabularnewline
Acidosis at birth (n{[}\%{]})\textsuperscript{+} & 2(5.3) & 0 &
0.52\textsuperscript{*}\tabularnewline
NICU admission (n{[}\%{]})\textsuperscript{+} & 30 (78.9) & 21 (91.3) &
0.29\textsuperscript{*}\tabularnewline
Perinatal death (n{[}\%{]}) & 4 (10) & 2(8.7) &
1\textsuperscript{*}\tabularnewline
\bottomrule
\end{longtable}

FGR: fetal growth restriction; GA: gestational age; NCIU: neonatal
intensive care unit

*Non-parametric test (Fisher-F or Mann-Whitney-U); + Stillbirths
excluded

\textbf{Table 2.} Angiogenic factors levels (median, interquartile
range)\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
& & \textbf{uncomplicated preeclampsia} (n=40) & \textbf{complicated
preeclampsia} (n=23) & \textbf{p*}\tabularnewline
\midrule
\endhead
At admission & PlGF(pg/mL) & 37(52.1) & 35.4(70.5) & 0.91\tabularnewline
& sFlt-1 (pg/mL) & 13453(9372) & 13120(9843) & 0.8\tabularnewline
& sFlt-1/PlGF ratio & 416.4(459.7) & 412.9(435.9) & 0.92\tabularnewline
At delivery & PlGF(pg/mL) & 27.1(45.4) & 42(29.5) & 0.81\tabularnewline
& sFlt-1 (pg/mL) & 16227(9773) & 23094(20501) & 0.15\tabularnewline
& sFlt-1/PlGF ratio & 705.7(782) & 674.8(834.5) & 0.62\tabularnewline
Delta values & PlGF(pg/mL)*day\textsuperscript{-1} & -1(4.2) & -1.4(7.9)
& 0.75\tabularnewline
& sFlt-1 (pg/mL)*day\textsuperscript{-1} & 343.7(1431.2) &
1079.5(3880.3) & 0.04\tabularnewline
& sFlt-1/PlGF ratio*day\textsuperscript{-1} & 24.2(77.2) & 19.1(72.4) &
0.32\tabularnewline
\bottomrule
\end{longtable}

\textbf{*} Mann-Whitney U test

\textbf{Table 3.} Logistic regression of the association to maternal
complications and Cox regression of the time interval from admission to
delivery (days)\selectlanguage{english}
\begin{longtable}[]{@{}llllllll@{}}
\toprule
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Coefficient\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
SE\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
p\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
OR/HR\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
95\% CI\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
95\% CI\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Lower\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Upper\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Logistic regression\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
sFlt-1 at admission\\
(log-transformed)\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
-0.49\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.56\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.385\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.61\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.21\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.84\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
PREP\_L risk score (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.06\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.02\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.012\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.06\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.01\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.12\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Delta sFlt-1 value\\
(log-transformed)\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
4.28\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.56\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.006\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
72.14\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
3.37\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1544\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Cox\\
regression\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
sFlt-1 at admission\\
(log-transformed)\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.17\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.29\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.546\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.19\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.68\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
2.09\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
PREP\_L risk score (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.03\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.01\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.004\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.03\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.01\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.05\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
Delta sFlt-1 value\\
(log-transformed)\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.15\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
0.32\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
\textless{}0.001\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
3.15\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
1.67\strut
\end{minipage} & \begin{minipage}[t]{0.10\columnwidth}\raggedright\strut
5.86\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

SE: Standard Error; OR: Odds Ratio; HR: Hazard Ratio

\textbf{Figure 1.} Prediction performance (receiver--operating
characteristic curves) for maternal complications of the baseline model
including PREP-L and sFlt-1 at admission (dashed line) vs. the model
where delta sFlt-1 value is added (dotted line).

\textbf{Figure 2.} Kaplan-Meier graph of the time interval from
admission to delivery (days) of women with delta sFlt-1 values in the
highest quartile (dashed line) vs. those the
1\textsuperscript{st}-3\textsuperscript{rd} quartile (solid line).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-1/Figure-1}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-2/Figure-2}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Supplementary-Figure-1/Supplementary-Figure-1}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Supplementary-Figure-2/Supplementary-Figure-2}

\end{center}
\end{figure}

\selectlanguage{english}
\FloatBarrier
\end{document}

