Evaluation of biochemical markers combined with uterine artery Doppler parameters in fetuses with growth restriction: a case–control study

First Trimester Placental Biomarkers for Pregnancy Outcomes

The placenta plays a key role in several adverse obstetrical outcomes, such as preeclampsia, intrauterine growth restriction and gestational diabetes mellitus. The early identification of at-risk pregnancies could significantly improve the management, therapy and prognosis of these pregnancies, especially if these at-risk pregnancies are identified in the first trimester. The aim of this review was to summarize the possible biomarkers that can be used to diagnose early placental dysfunction and, consequently, at-risk pregnancies. We divided the biomarkers into proteins and non-proteins. Among the protein biomarkers, some are already used in clinical practice, such as the sFLT1/PLGF ratio or PAPP-A; others are not yet validated, such as HTRA1, Gal-3 and CD93. In the literature, many studies analyzed the role of several protein biomarkers, but their results are contrasting. On the other hand, some non-protein biomarkers, such as miR-125b, miR-518b and miR-628-3p, seem to be linked to an increased risk of complicated pregnancy. Thus, a first trimester heterogeneous biomarkers panel containing protein and non-protein biomarkers may be more appropriate to identify and discriminate several complications that can affect pregnancies.

Serial measurement of soluble endoglin for risk assessment at the diagnosis of fetal growth restriction

AIM

In this study, we aimed to investigate the soluble endoglin (sEng) levels in pregnant women with fetal growth restriction (FGR) and to examine the possible relation of the sEng levels with the time remaining to delivery and maternal and fetal complications.

METHODS

A total of 42 pregnant women diagnosed with FGR were retrospectively reviewed. Using the maternal blood samples it is at the collected 24-37 gestational weeks, the sEng levels were measured. Fetal biometry measurements, umbilical artery, uterine artery, middle cerebral artery Doppler indices were documented.

RESULTS

Of all patients, 17 (40%) were diagnosed with early-onset FGR, while 25 (60%) were diagnosed with late-onset FGR. Abnormal Doppler findings were present in 25 (60%) patients. Of 42 newborns, 18 (42%) were hospitalised in the neonatal unit. The mean sEng level calculated by taking the average of the first and second blood samples was 63.24 ± 49.83 ng/mL. There was no statistically significant difference in the mean sEng levels between those who gave birth within four, three, and two weeks after the diagnosis of FGR and those who did not. There was a positive significant correlation between the mean sEng levels and systolic blood pressure (r = 0.319, P = .04).

CONCLUSIONS

We did not find a statistically significant relationship between the sEng level and the time remaining to the time of delivery in pregnant women with FGR. We found no statistically significant difference in sEng level between the groups in pregnant women with fetuses with FGR with or without maternal and fetal complications.

Maternal alpha-1-antitrypsin as a noval marker for growth restriction in pre-eclampsia

AIM

To verify the role of maternal serum levels of alpha-1-antitrypsin (AAT), an acute-phase inflammatory protein, as a marker for distinguishing between fetal growth restriction (FGR) and normal birth weight in pre-eclamptic women. We correlate serum AAT levels to the essential feto-maternal parameters for an earlier and cost-benefit diagnostic method, thus distinguishing between FGR and normal birth weight in pre-eclamptic women.

METHODS

An observational study conducted at the University hospital recruited 100 pregnant women in 32/34 weeks of a singleton single tone pregnancy; all were pre-eclampsia cases. All were tested by laboratory and ultrasound examination. Two sets of data were collected; one is maternal parameters such as blood pressure (BP), maternal serum AAT mean platelet volume (MPV), platelet distribution width (PDW), and serum uric acid levels, and the other is fetal parameters such as amniotic fluid index (AFI), fetal weight centile and estimated fetal weight.

RESULTS

A strong negative correlation proved between serum levels of AAT and all study variables except fetal weight (systolic BP, diastolic BP, MPV, PDW, serum uric acid, fetal weight percentile, and AFI) with a correlation coefficient of; -0.95, -0.95, -0.85, -0.93, -0.91, -0.94, and -0.93 respectively. The cut-off value for AAT 0.013 mg/ml showed the highest sensitivity and specificity as a diagnostic marker for FGR. Area under the curve was 0.99.

CONCLUSIONS

Negative correlations between maternal serum AAT and fetal parameters used to assess FGR were confirmed, suggesting that AAT is closely related to the pathophysiology of FGR among pre-eclamptic patients and may serve as a helpful tool in distinguishing between FGR and normal birth weight babies, pending further validation in feto-maternal outcomes.

Physiopathology of late-onset fetal growth restriction

Fetal growth restriction (FGR) is defined as the inability of the fetus to reach its potential for genetic determination. FGR can have several causes, including genetic syndromes, chromosomal diseases, and infections; however, a vast majority of cases are probably attributed to impaired uterine and placental circulation. The relationships between abnormal placental development and FGR are complex, and studies are generally few, presenting confounding factors. Damage to the uteroplacental circulation associated with vasculogenesis and villus angiogenesis dysfunction are the main factors involved in subsequent FGR. The main receptors involved in FGR include hypoxia-inducible factor (HIF 1, 2, and 3), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), vascular endothelial growth factor C (VEGF-C), soluble Flt-1, soluble endoglin (Seng), angiopoietin-1 and -2 (Ang-1 and Ang-2), tyrosine kinase receptor 1 (Flt-1), tyrosine kinase receptor 2 (Flt-2), vascular endothelial growth factor receptor (VEGFR) 1, 2 and 3, kinase domain receptor (KDR), and vascular endothelial growth factor receptor A (VEGFR-A). Furthermore, failure in trophoblastic invasion and remodeling of spiral arteries has been associated with FGR owing to poor placental perfusion. There are several possible causes for poor remodeling of spiral arteries, which probably vary on a case-to-case basis. Changes in the placental form, macroscopic and microscopic vascular lesions, inflammation, and genetic changes are also related to FGR. Based on gestational age at diagnosis, FGR can be classified as early- (˂32 weeks) and late-onset (≥32 weeks). Moreover, there exist several theories regarding possible pathophysiological differences between early- and late-onset FGR, with some postulating that it the same disease but at different stages or severity. Another hypothesis suggests that the change in the trophoblastic invasion of spiral arteries would be milder. In this article, we address the main mechanisms described in the pathophysiology of FGR and, later, the specific findings in late-onset FGR.

Midregional pro-adrenomedullin and matrix metalloproteinase-2 levels in intrauterine growth restriction and small gestational age pregnancies: biochemical diagnostic difference

OBJECTIVE

Midregional pro-adrenomedullin (MR-proADM) and matrix metalloproteinase-2 (MMP-2) are such proteins, that decreased levels are demonstrated in defective placental functions, as preeclampsia. The aim of the study is to compare maternal serum MR-proADM and MMP-2 levels across pregnancies with intrauterine growth restriction (IUGR), small for gestational age (SGA) and appropriate for gestational age (AGA), to biochemical screen the difference between SGA and IUGR.

MATERIALS AND METHODS

180 pregnant women were enrolled in a cross-sectional study: sixty pregnancies diagnosed for IUGR were included in group 1 (IUGR group), sixty pregnancies with SGA were in Group 2 (SGA group) and sixty pregnancies diagnosed for AGA, as control group. Maternal venous blood samples were collected at the time of enrollment, to assess serum MR-proADM and MMP-2 levels, by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean maternal serum MR-proADM and MMP-2 levels were lower in the IUGR group than in the SGA and AGA groups (p < .001 and p < .001). Maternal serum MR-proADM and MMP-2 cutoffs of 29.985 pg/mL and 1.875 ng/mL were found to be optimal to distinguish IUGR, with sensitivity of 98.3% and 98.3%, specificity of 83.3% and 89.2%, respectively.

CONCLUSION

Maternal serum MR-proADM and MMP-2 levels were significantly lower in pregnancies with IUGR. Maternal serum MR-proADM and MMP-2 measurements could be used to distinguish IUGR pregnancies from SGA pregnancies.

Assessing the sensitivity of placental growth factor and soluble fms-like tyrosine kinase 1 at 36 weeks' gestation to predict small-for-gestational-age infants or late-onset preeclampsia: a prospective nested case-control study

Background

Fetal growth restriction is a disorder of placental dysfunction with three to four-fold increased risk of stillbirth. Fetal growth restriction has pathophysiological features in common with preeclampsia. We hypothesised that angiogenesis-related factors in maternal plasma, known to predict preeclampsia, may also detect fetal growth restriction at 36 weeks’ gestation. We therefore set out to determine the diagnostic performance of soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF), and the sFlt-1:PlGF ratio, measured at 36 weeks’ gestation, in identifying women who subsequently give birth to small-for-gestational-age (SGA; birthweight <10th centile) infants. We also aimed to validate the predictive performance of the analytes for late-onset preeclampsia in a large independent, prospective cohort.

Methods

A nested 1:2 case-control study was performed including 102 cases of SGA infants and a matched group of 207 controls; and 39 cases of preeclampsia. We determined the diagnostic performance of each angiogenesis-related factor, and of their ratio, to detect SGA infants or preeclampsia, for a predetermined 10% false positive rate.

Results

Median plasma levels of PlGF at 36 weeks’ gestation were significantly lower in women who subsequently had SGA newborns (178.5 pg/ml) compared to normal birthweight controls (326.7 pg/ml, p < 0.0001). sFlt-1 was also higher among SGA cases, but this was not significant after women with concurrent preeclampsia were excluded. The sensitivity of PlGF to predict SGA infants was 28.8% for a 10% false positive rate. The sFlt-1:PlGF ratio demonstrated better sensitivity for preeclampsia than either analyte alone, detecting 69.2% of cases for a 10% false positive rate.

Conclusions

Plasma PlGF at 36 weeks’ gestation is significantly lower in women who subsequently deliver a SGA infant. While the sensitivity and specificity of PlGF currently limit clinical translation, our findings support a blood-based biomarker approach to detect late-onset fetal growth restriction. Thirty-six week sFlt-1:PlGF ratio predicts 69.2% of preeclampsia cases, and could be a useful screening test to triage antenatal surveillance.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1992-x) contains supplementary material, which is available to authorized users.

Second trimester maternal serum-amniotic fluid nitric oxide and vascular endothelial growth factor levels in relation to uterine artery Doppler indices in pregnancies with normal outcome

The aim of the present study was to explore the possible relations of maternal serum and amniotic fluid nitric oxide (NO) and of vascular endothelial growth factor A (VEGF-A) concentrations with uterine artery Doppler indices (UtADs) in a healthy second trimester obstetric population. In this regard, the levels of NO and VEGF-A were measured in maternal sera and the amniotic fluid samples were in 36 subjects who were in their early second trimester of pregnancy. The mean levels for VEGF-A were 110.3 ± 31.5 pg/ml in maternal serum and 149.6 ± 31.3 pg/ml in amniotic fluid. Mean levels for NO were 5.7 ± 4.7 µmol in maternal serum and 12.9 ± 3.4 µmol in amniotic fluid. UtADs were measured concurrently with the sample collections. The mean value for uterine artery pulsatility index (PI) was 1.3 ± 0.4. The measurements were then analysed for possible correlations, whereby no correlation was found between UtAD and maternal serum levels of either molecule (p = .828 and p = .662 for VEGF-A and NO, respectively). However, a positive correlation was found between the NO levels in the amniotic fluid compartment and UtAD (r = 0.432, p = .009 for PI). Therefore, a correlation of UtAD with amniotic fluid NO can be expected in pregnancies with a normal outcome. Impact Statement What is already known on this subject? Nitric oxide (NO) and vascular endothelial growth factor A (VEGF-A) are important vasoactive molecules that play significant roles in early angiogenesis and placentation. What the results of this study add? There is a positive correlation between the amniotic fluid NO levels and the uterine artery Doppler indices (UtADs) in the second trimester of pregnancies with normal outcomes. What the implications are of these findings for clinical practice and/or future research? A correlation between amniotic fluid NO levels and UtAD may indicate a normal trophoblastic invasion. Disturbance of this balance may be expected in certain adverse pregnancy outcomes. Additional studies are needed to further explore the molecular signs of early abnormal placentation and their clinical reflection.

Maternal serum homocysteine and uterine artery Doppler as predictors of preeclampsia and poor placentation

PURPOSE

The aim of this study was to evaluate the role of maternal serum total Homocysteine (tHcy) and uterine artery (Ut-A) Doppler as predictors of preeclampsia (PE), intrauterine growth restriction (IUGR), and other complications related to poor placentation.

PATIENTS AND METHODS

A prospective cohort study was conducted on 500 women with spontaneous pregnancies. tHcy was measured at 15-19 weeks, and then, Ut-A Doppler was performed at 18-22 weeks of pregnancy.

RESULTS

453 pregnant women completed the follow-up of the study. The tHcy and Ut-A resistance index were significantly higher in women who developed PE, IUGR, and other complications when compared to controls (tHcy: 7.033 ± 2.744, 6.321 ± 3.645, and 6.602 ± 2.469 vs 4.701 ± 2.082 μmol/L, respectively, p value <0.001 and Ut-A resistance index: 0.587 ± 0.072, 0.587 ± 0.053, and 0.597 ± 0.069 vs 0.524 ± 0.025, respectively, p value <0.001). The use of both tHcy assessment and Ut-A Doppler improved the sensitivity of prediction of PE relative to the use of each one alone (85.2 relative to 73.33 and 60%, respectively).

CONCLUSION

The use of elevated homocysteine and uterine artery Doppler screening are valuable in prediction of preeclampsia, IUGR, and poor placentation disorders. CLINCALTRIAL.

GOV ID

NCT02854501.

Fetal growth restriction: current knowledge

BACKGROUND

Fetal growth restriction (FGR) is a condition that affects 5-10% of pregnancies and is the second most common cause of perinatal mortality. This review presents the most recent knowledge on FGR and focuses on the etiology, classification, prediction, diagnosis, and management of the condition, as well as on its neurological complications.

METHODS

The Pubmed, SCOPUS, and Embase databases were searched using the term "fetal growth restriction".

RESULTS

Fetal growth restriction (FGR) may be classified as early or late depending on the time of diagnosis. Early FGR (<32 weeks) is associated with substantial alterations in placental implantation with elevated hypoxia, which requires cardiovascular adaptation. Perinatal morbidity and mortality rates are high. Late FGR (≥32 weeks) presents with slight deficiencies in placentation, which leads to mild hypoxia and requires little cardiovascular adaptation. Perinatal morbidity and mortality rates are lower. The diagnosis of FGR may be clinical; however, an arterial and venous Doppler ultrasound examination is essential for diagnosis and follow-up. There are currently no treatments to control FGR; the time at which pregnancy is interrupted is of vital importance for protecting both the mother and fetus.

CONCLUSION

Early diagnosis of FGR is very important, because it enables the identification of the etiology of the condition and adequate monitoring of the fetal status, thereby minimizing risks of premature birth and intrauterine hypoxia.

Correlation between maternal serum-amniotic fluid anti-angiogenic factors and uterine artery Doppler indices

PURPOSE

Elevated sFlt-1 and sEng is usually a clue for impending preeclampsia and intrauterine growth restriction. Likewise, uterine artery Doppler ultrasound is being investigated for prediction of similar conditions. In this study, we aimed to explore the possible relations of these two proteins in different body compartments with uterine artery Doppler indices (UtAD) in a healthy second trimester obstetric population.

METHODS

Levels of sFlt-1 and sEng were measured in serum and amniotic fluid samples of 43 patients. UtAD were measured on the days of sample collections. Findings were then analyzed for possible correlation.

RESULTS

There was a positive correlation between the levels of maternal serum sFlt-1 (MSsFlt-1) and sEng levels (MSsEng) (r= 0.516, p< 0.001). The negative correlation between MSsFlt-1 and UtAD was disappeared after elimination of poor obstetric outcome pregnancies (r= -0.371, p= 0.016). No correlation was found between UtAD and studied protein levels in amniotic fluid. Mean MSsFlt-1 level was 305.2 ± 220.1 pg/ml and mean AFsFlt-1 was 48.9 ± 11.8 ng/ml. Mean MSsEng level was 4.5 ± 1.3 ng/ml, mean AFsEng level was found 0.7 ± 0.3 ng/ml. Mean values for UtAD were 1.3 ± 0.4, 0.6 ± 0.1 and 3.5 ± 1.3 for PI, RI, and S/D, respectively.

CONCLUSION

In normal second trimester pregnancies, there is a positive correlation between serum levels of sFlt-1 and sEng levels. Amniotic fluid levels of sEng and sFlt-1 are not correlated with UtAD in uncomplicated pregnancies.