perinatal.pdf

8/16/2019 perinatal.pdf

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1 I

st Department of Gynecological Oncology and Gynecology, Medical University in Lublin

2II

nd Department of Obstetrics and Pathological Pregnancy, Medical University in Lublin

Archives of Perinatal Medicine 17 4), 199-203, 2011 ORIGINAL PAPER

Placental growth factor (PLGF) with PAPP-A

and free beta hCG assessment in women

between 11

th

and 14

th

weeks of gestation A RTUR CZEKIERDOWSKI1, SYLWIA CZEKIERDOWSKA 1, A RKADIUSZ K RZYŻ ANOWSKI2,

J ANUSZ K RACZKOWSKI2, EWELINA R OGALA 1, A LDONA NOWICKA 1

Abstract

Preeclampsia (PE) remains one of the leading causes of maternal, fetal and neonatal mortality and morbidity

worldwide. Early identification of a subgroup of patients with an increased risk for PE became one of the most

important goals in perinatal medicine. Our objective was to examine the possible relationship of PLGF measure-

ments in late 1st trimester of pregnancy with selected maternal clinical features, maternal serum concentrations

of pregnancy-associated plasma protein-A (PAPP-A), free $-human chorionic gonadotropin ($-hCG) and variouslate pregnancy complications. The studied group included 113 pregnant women with singleton pregnancies bet-

ween 11 weeks+0 days and 13 weeks +6 days of gestation. Mean age of these women was 38.8 years (range: 16

to 42 years). Mean neonatal weight at delivery was 3367 g (median – 3460 g, min-max 150-5660 g). Median mater-

nal serum PLGF concentration was 32.38 pg/ml (interquartile range: 23.6-46.6 pg/ml, SD = 51.18 pg/mol, min-

max = 10.1-593.5 pg/ml). Median concentrations of PLGF decreased with the increase of gestational age. Normal

vaginal delivery occurred in 52 women in the studied group and there were 61 cesarean sections performed for

various indications. Mean body mass index (BMI) value of studied pregnant women was 24.3 ± 4.1 (min-max: 18.4-

38.2). Fetal crown-rump length (CRL) ranged from 45 mm to 83mm and measured nuchal translucency (NT)

values ranged from 1.01 to 3.1 mm (median – 1.91 mm). Multiple of the Medians (MoM’s) of free beta HCG and

PAPP-A were 0.73 (range: 0.51-1.07) and 3.08 (range: 1.81-4.94), respectively. A significant correlation between

maternal serum PLGF concentrations and fetal CRL in the late 1st trimester of gestation was found R = 0.19;

p = 0.04). No statistically significant correlations were found between maternal serum PLGF levels and other stu-

died parameters such as: maternal BMI, fetal NT, and calculated MoM’s of free beta HCG as well as PAPP-A inmaternal serum (all p ’s > 0.005). We conclude that serum placental growth factor measurements in the late 1

st

trimester may provide additional prognostic value in predicting various late pregnancy complications including

preeclampsia.

Key words: early pregnancy, placental growth factor (PLGF), PAPP-A, preeclampsia screening

Prediction of fetal and maternal risk is the main goal

of perinatal care. Despite numerous conducted studies,

hypertensive disorders in pregnancy and, in particular,

preeclampsia (PE) remain one of the leading causes of

maternal, fetal and neonatal mortality and morbidity worldwide [4, 8]. Since in many countries a late first-

trimester screening for fetal aneuploidy is now offered

in general population of healthy pregnant women, the

early identification of a subgroup of patients with an in-

creased risk for PE became one of the most important

goals in perinatal medicine [3, 11, 16 ]. The most impor-

tant disorders in preeclampsia and intrauterine growth

retardation are associated with placental malfunction

[17]. Abnormal trophoblast invasion late in the 1st tri-

mester, accompanied by the absence of appropriate ma-

ternal spiral artery modification with the resulting pla-

cental ischemia are all associated with the release of se-

veral specific molecules, mostly proteins, as well as cell-

free fetal DNA and RNA [13, 16, 17]. These molecules

can now be detected in the maternal blood, and changesin their concentrations can be further used for early

identification and prediction of preeclampsia, long before

to the appearance of the typical clinical symptoms of

hypertension with proteinuria [16, 17].

Currently, for women between 11th and 14

th week of

gestation several biophysical and biochemical markers

have been proposed, most frequently in a combinatory

analysis [14]. Some of early predictors or diagnostic

tools of preeclampsia include measurements of preg-

nancy associated protein A (PAPP-A), placental growth


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A. Czekierdowski, S. Czekierdowska, A. Krzy ż anowski et al.200

factor (PLGF), placental protein 13 (PP-13), vascular

endothelial growth factor (VEGF) and it’s receptors

(VEGF-R) [7, 10, 18, 19]. It has been also found that ab-

normal maternal uterine artery Doppler in association

with elevated maternal serum AFP, hCG, or inhibin-A or

decreased PAPP-A may effectively identify a group of wo-

men at greater risk of IUGR and gestational hyper-

tension with proteinuria. Uterine artery Doppler measu-

rements may be used in the evaluation of an unexplained

abnormal level of either of these markers [5, 6]. PLGF

is a dimeric glycoprotein that is secreted to maternal

blood and is capable of strong angiogenic and mitogenic

activities that in turn can induce the proliferation, mig-

ration, and activation of endothelial cells [12]. In 2008

Akolekar et al. [1] have found that significant contribu-

tions for the prediction of PE were provided by maternalcharacteristics and obstetric history, serum PLGF and

uterine artery pulsatility index (PI) measured at 11-14

weeks of gestation and with combined screening the de-

tection rates for early PE and late PE were 90% and 49%,

respectively, for a false-positive rate of 10%.The authors

have suggested that effective screening for PE can be

provided by a combination of maternal characteristics

and obstetric history, uterine artery PI and maternal

serum PLGF at 11 + 0 to 13 + 6 weeks' gestation.

Our objective was to examine the possible relation-ship of PLGF measurements in late 1

st trimester of preg-

nancy with selected maternal clinical features, maternal

serum concentrations of pregnancy-associated plasma

protein-A (PAPP-A), free β-human chorionic gonado-

tropin (β-hCG) and various late pregnancy complications.

Methods

The study population included 113 singleton preg-

nant women who attended the prenatal screening prog-

ram in Lublin, between August 2009 and March 2010.

All pregnant women who accepted the first-trimester

screening test had blood drawn at the first visit at ul-

trasound screening unit between gestational weeks 11 +

0 days and 13 + 6 days. In each pregnant women ultra-

sound scan according to FMF guidelines was performed

with the use of transabdominal probe RAB 4-8 MHz of

the GE Voluson E8 scanner. Following parameters were

measured: fetal crown-rump length (CRL), biparietal dia-

meter (BPD), femur length (FL) and nuchal translucency

(NT) as well as fetal heart rate (FHR). Following ultra-

sound examination a venous blood sample was drawn in

each patient. All samples were centrifuged to separate

serum which was next was frozen in !80EC until further

analysis. The serum samples were analyzed at Multimed

(Warsaw) laboratory. Levels of PAPP-A and free β-hCG

were determined by the Delfia Express (Perkin Elmer,

Turku, Finland) method and registered in the electronic

database of biochemical test results by the unique pa-

tient identifier. The PAPP-A and free β-hCG serum va-

lues were converted to multiples of the median (MoM)

values by expressing the absolute concentration relative

to the median value for the gestational age at the day of

blood sampling. MoM values were corrected for mater-

nal weight (as a continuous variable). PLGF was mea-

sured with an ELISA method. A second ultrasound exa-

mination was performed again in weeks 18-22, when the

fetus was examined for structural abnormalities; specific

measures were recorded in the clinical database. The

scans were all performed by sonographers certified to

perform NT measurement by The Fetal Medical Foun-dation, London, UK. Data regarding all variables derived

from the ultrasound measures in the antenatal screening

program as well as the biomarkers were obtained from

the Astraia Database (www.astraia.com), which is a data-

base developed for clinical purposes such as documen-

tation and individual risk assessment. Only certified

sonographers and medical doctors have access to type in

data in the Astraia Database.

Information about delivery week and neonatal birth

weight at delivery, as well as possible delivery complica-tions was obtained from women themselves or from the

hospital data bases. The registration forms were comple-

ted by the attending midwife, further they were manually

checked and compared with the medical charts by a re-

search midwife, before data entry. Multiple logistic reg-

ression analyses and other statistical tests were used as

appropriate to estimate a potential explanation of the

association of other variables (maternal age, maternal

body mass index (BMI), week at delivery, fetal biometry,

MoM’s of PAPP-A and free beta HCG, neonatal weight).

The statistical software package STATISTICA v.6.0 (Stat-

soft,USA) was used for the data analyses. Value p of <

0.05 was considered statistically significant.

Results

Mean age of studied women was 38.8 years (range:

16 to 42 years). Mean neonatal weight at delivery was

3367 g (median – 3460 g, min-max 150-5660 g). Mean

body mass index (BMI) value of studied pregnant women

was 24.3±4.1 (min-max: 18.4-38.2). Fetal crown-rump

length (CRL) ranged from 45 mm to 83 mm and measu-

red nuchal translucency (NT) values ranged from 1,01 to

3.1 mm (median – 1.91 mm). Median maternal serum

PLGF concentration was 32.38 pg/ml (interquartile


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Placental growth factor (PLGF) with PAPP-A and free beta hCG assessment 201

Table 1. Means and medians of PLGF serum concentrations in early gestation

Weeks of gestation SD MDRange

(Min-max.)Interquartile range P value

11wekks + 0 days to 11weeks+ 6days 47,9 39,9 15.9-139 25.9-48.3H = 1.53;

p = 0.46

12weeks+0 days to 12 weeks + 6 days 57.1 32.9 10.9-593 24.3-56.4

13weeks + 0 days to13weeks + 6 days 44.1 31.8 10.1-253 21-40

Table 2. Selected clinical, sonographic and biochemical parameters with birth weight characteristics and pregnancy

complications compared to PLGF levels in late 1st trimester of gestation

NumberNeonatal birth weight

(median and range)

Statistical

analysis

PLGF pg/ml

(median, range)

Statistical

analysis

No complications N = 90 3456 g (2010 g-5660 g) Z = 0.9;

p = 0.33

34.9 (24.3-48.7) Z = 1.95;

p = 0.05Complications N = 23 3350 g (2700 g-3790 g) 25.5 (22.3-34.2)

Type of delivery

Normal vaginal delivery N = 52 3600 g (3200 g-3850 g) Z = !2.68; p = 0.007

33.9 (24.6-48.7) Z =!0.68; p = 0.49Cesarean section N = 61 3360 g (2800 g-3620 g) 32.2 (22.3-46.2)

Hypertensive disorders of pregnancy

No hypertension N = 107 3450 g (3100 g-3705 g) Z = !1.28;

p = 0.19

33.3 (23.6-47.6) Z = 0.5;

p = 0.5Hypertensive disorders in late gestation N =6 3715 g (3360 g-4050 g) 30.1 (23.8-36.4)

Time of delivery

Term delivery N =104 3480 g (3180 g-3800 g) Z =3 .6;

p = 0.0003

33.4 (23.8-47.6) Z = 0.5;

p = 0.5Preterm delivery(< 37 weeks) N = 9 2600 g (2420 g-3170 g) 27.6 (18.2-46.6)

range: 23.6-46.6 pg/ml, SD = 51.18 pg/mol, min-max =10.1-593.5 pg/ml). Median concentrations of PLGF de-

creased with the increase of gestational age. During the

11th week of gestation the median PLGF level was 39.9

pg/ml (range: 25.9-48.3 pg/ml), whereas in the 12th week

of gestation the median level was 32.9 pg/ml (range:

24.3-56.4 pg/ml). In the 13th week of gestation the

median serum PLGF concentration was 31.8 pg/ml (ran-

ge: 21-40 pg/ml). These values were not statistically dif-

ferent between particular weeks of pregnancy (H = 1.53;

p = 0.46). Normal vaginal delivery occurred in 52 women

of the studied group and there were 61 cesarean sec-

tions performed for various indications. There were two

stillbirths and 2 neonates were born alive with severe

genetic disorders, one Down syndrome and one Turner

syndrome. Nineteen other pregnancies had minor obs-

tetrical or neonatal complications at delivery.

Calculated multiples of the medians (MoM’s) of free

beta HCG and PAPP-A were 0.73 (range: 0.51-1.07) and

3.08 (range: 1.81-4.94), respectively. Spearman’s rank

correlation test indicated statistically significant corre-

lation between maternal serum PLGF concentrations

and fetal CRL in the late 1st trimester of gestation R =

0.19; p = 0.04). No statistically significant correlations

were found between maternal serum PLGF levels and

other studied parameters such as: maternal BMI, fetalNT, and calculated MoM’s of free beta HCG as well as

PAPP-A in maternal serum (all p ’s > 0.005).

Median serum PLGF concentrations in a group of

women with no pregnancy complications was 34.9 pg/ml

(range: 24.3-48.7 pg/ml), whereas in women with any

detected pregnancy complication and/or congenital birth

defects the median PLGF concentration was 25.5 pg/ml

(22.3-34.2 pg/ml). The differences between these groups

were close to statistically significant correlation (Z =

1.95; p = 005). However, the median birth weight did not

differ significantly between both groups (Z = 0.9; p =

0.33).

There were 6 cases of pregnancy induced hyperten-

sion in the studied group. The median PLGF serum

concentrations did not differ between these groups (Z =

0.5; p = 0.5). No significant difference was found bet-

ween the medians of neonatal birth weights (Z = !1.28;

p = 0.19).Term delivery occurred in 104 women of the

studied group and 9 women had preterm delivery. Again,

the medians of PLGF maternal serum concentrations did

not differ between these groups (Z = 0.5; p = 0.5).

Median neonatal birth weight was significantly higher in

women with term deliveries (Z = 3.6; p = 0.0003). The

mode of delivery either vaginal or cesarean section was


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A. Czekierdowski, S. Czekierdowska, A. Krzy ż anowski et al.202

not correlated with the late 1st trimester maternal serum

PLGF concentrations (Z = !0.68; p = 0,49). The median

neonatal birth weight following vaginal delivery was signi-

ficantly higher than the median birth weight following

cesarean section delivery (Z =!2.68; p = 0.007). Spear-

man’s rank correlation test indicated no significant corre-

lations between early pregnancy maternal PLGF con-

centrations and neonatal birth weight R = 0.1; p = 0.29).

Discussion

There is an increasing evidence that various fetal

and maternal late pregnancy complications might be

established in early 1st trimester. Recently, it has been

postulated that the combination of slow early fetal

growth and low PAPP-A resulted in a nearly six-fold in-

creased risk of delivery of an SGA infant [9]. In the first trimester, an unexplained low PAPP-A (< 0.4 MoM)

and/or a low hCG (< 0.5 MoM) are associated with an

increased frequency of adverse obstetrical outcomes,

and, at present, no specific protocol for treatment is

available [17]. It has been recently shown that decreased

PlGF levels were observed prior to 20 weeks of gesta-

tion in women who subsequently develop preeclampsia

[18, 19].

Cowans et al. [2] suggested that low levels of first-

trimester PLGF provide a good indicator of SGA compli-

cations and some hypertensive disorders, in particular

severe cases of PE such as early onset and HELLP synd-

rome. Low levels of placental growth factor expressed as

the lowest third centile at both samplings was associated

with high risk of SGA with the odds ratio of 3.8 and 95%

confidence interval of 1.6- 8.8 [15]. Also, if the increase

from the lowest to the highest third of soluble Flt-1 was

found in examined samples, there was a substantial

increase in SGA neonate risk with the odds ratio of 6.2

with 95% confidence interval of 2.4-16.1. In the same

study women with high soluble endoglin serum concen-

tration expressed as the highest third centile at the

second sampling had approximately a 3.5-fold increased

risk of SGA. The authors have concluded that the finding

of low maternal soluble Flt-1 in early pregnancy subse-

quently followed by an increase in soluble Flt-1 and rise

in soluble endoglin concentrations was associated with

a significantly increased risk of severe fetal growth re-

striction in late pregnancy. These findings might impro-

ve our chances of early identification of fetuses at in-

creased risk of growth restriction. In such selected highrisk cases increased pregnancy surveillance might re-

duce the risk of adverse fetal outcome and maternal

pregnancy related disease.

It is possible that new modalities of non-invasive

examination might prove more cost-effective to imple-

ment methods for the early identification of fetuses at

high risk of later adverse outcome than to offer third-

trimester ultrasound scans with fetal weight estimation

to the entire population. Since PAPP-A, free β-hCG and

measures of early fetal growth are already assessed in

pregnant women participating in prenatal screening

programs, the use of these modalities in early identifi-

cation would be at no or relatively small extra cost [5, 9,

19]. Early risk assessment might be based on PAPP-A,

free β-hCG and PLGF, perhaps combined with maternal

blood pressure measurements with other serum mar-

kers, uterine artery Doppler flow assessment [4, 14].

There are also some new possibilities of three-dimen-

sional ultrasound measures of placental volume and vas-cular blood flow.

When increased risk for PE development is found it

is crucial to plan both pregnancy surveillance strategy

and pharmacological treatment options. Treatment stra-

tegies may include antihypertensive drugs, low salt and

non saturated fatty acid rich diet and most of all more

frequent non-invasive biochemical and sonographic te-

sting of pregnancy status. The findings of our study sup-

port the view that combined measurements of PAPP-A,

f-beta hCG and PLGF are highly valuable tool for thenon-invasive detection of PE risk group. In such cases an

exact diagnosis followed by possibly best adjusted and

timely intervention, for example aspirin/ heparin treat-

ment or induction of fetal lung maturation would be

potentially of a great value in decreasing the frequency

of the most serious preeclampsia complications. More-

over, a recruitment for future studies searching new the-

rapeutic interventions and additional prospective mar-

kers could be improved. Understanding relations among

maternal characteristics and levels of angiogenic factors

may help to design studies that use these markers to

examine etiology and to predict potential adverse preg-

nancy outcome. Production and concentration of various

biomarkers are ultimately dependent on genetic factors.

It has been suggested that new genomic studies are

likely to detect genetic variants associated with pre-

eclampsia. However, in contrast to the static genome,

the proteome is dynamic. Whereas the genome will not

change during pregnancy or pregnancy-associated condi-

tions such as preeclampsia, the proteome could be chan-

ged by various modifying internal and environmental fac-tors. It is therefore likely that new proteomic and meta-

bolomic studies that will use a large number of biomar-

kers will be able to indicate these truly effective in scree-


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Placental growth factor (PLGF) with PAPP-A and free beta hCG assessment 203

ning molecules. These markers could potentially be

more accurate in predicting increased risk of preeclamp-

sia than time-consuming and costly genomic studies. Ob-

viously, larger studies are needed to confirm these find-

ings.

Our prenatal screening program covers the popula-

tion in a large area and is free of charge. Accordingly, we

believe that our study population is highly represen-

tative, without oversampling of high-risk pregnancies.

Despite the limitations in sample size and exploratory

nature of the study, we conclude that placental growth

measurements in the late 1st trimester in pregnant wo-

men blood serum may provide additional prognostic

value in predicting various late pregnancy complications

including preeclampsia. Based on published evidence

and on our current study results we believe that a panelof markers presented above may be used in clinical prac-

tice to detect women at increased risk of preeclampsia.

Obviously, further studies are required before any firm

conclusion can be reached.

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J Artur Czekierdowski

Ist Department of Gynecological Oncology

and Gynecology

Medical University in Lublin

20-081 Lublin, Staszica 16

e-mail: [email protected]

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