Intraplacental villous artery resistance indices and identification of placenta-mediated diseases

Umbilical artery ultrasound haemodynamics combined with serum adiponectin levels can aid in predicting adverse pregnancy outcomes in patients with severe pre-eclampsia

Severe pre-eclampsia is a leading cause of maternal and perinatal morbidity and mortality. This retrospective study explored pregnancy outcome predictive values of umbilical artery Doppler with serum adiponectin in severe pre-eclampsia. Fasting elbow venous blood was collected from 118 severe pre-eclampsia patients [maternal systolic pressure ≥ 160 mmHg and/or diastolic pressure ≥ 110 mmHg + minimal proteinuria, 56; mild hypertension + heavy proteinuria (≥2 g/24 h or random urinary protein ≥ 2+), 42; no proteinuria but new-onset hypertension + diseases of heart/lung/liver/kidney/other organs or abnormalities in blood/digestive/nervous systems, placental foetus involved, 20] and 90 controls (18.5-24.9 kg/m²) in the first morning of admission. Serum adiponectin and resistance/pulsatility indexes were separately measured and correlatively analysed by Pearson's coefficient analysis. Adverse outcomes included maternal primary postpartum haemorrhage and placental abruption, neonatal asphyxia, low birth weight, foetal distress, foetal growth restriction. In severe pre-eclampsia, serum adiponectin (downregulated) was negatively-correlated with resistance/pulsatility indexes (upregulated). The area under the curve of umbilical artery Doppler with serum adiponectin for predicting adverse outcomes of severe pre-eclampsia was 0.6545 (specificity 60.27%, sensitivity 60.00%). In conclusion, umbilical artery Doppler with serum adiponectin predicts adverse pregnancy outcomes in severe pre-eclampsia.Impact statementWhat is already known on this subject? Sad levels were lowered in sPE patients. UA ultrasound hemodynamic parameters can predict adverse pregnancy outcomes.What do the results of this study add? Our study revealed that ultrasonic hemodynamic indexes of UA combined with Sad levels had better efficacy in predicting pregnancy outcomes in patients with sPE, and our study is expected to improve the accuracy of clinical prediction of adverse outcomes in sPE patients.What are the implications of these findings for clinical practice and/or further research? Through the combined detection of multiple indicators of the foetus in the mother, our study expects to be able to monitor and predict the growth of the foetus in the mother more accurately in clinical practice, avoid excessive intervention or untimely intervention, and reduce the incidence of perinatal adverse pregnancy outcomes.

Effectiveness of Scutellaria baicalensis Georgi root in pregnancy-related diseases: A review

The root of Scutellaria baicalensis Georgi, also called Huangqin, is frequently used in traditional Chinese medicine. In ancient China, S. baicalensis root was used to clear heat, protect the fetus, and avoid a miscarriage for thousands of years. In modern times, pregnancy-related diseases can seriously affect maternal and fetal health, but few systematic studies have explored the mechanisms and potential targets of S. baicalensis root in the treatment of pregnancy-related diseases. Flavonoids (baicalein, wogonin and oroxylin A) and flavonoid glycosides (baicalin and wogonoside) are the main chemical components in the root of S. baicalensis. This study presents the current understanding of the major chemical components in the root of S. baicalensis, focusing on their traditional uses, potential therapeutic effects and ethnopharmacological relevance to pregnancy-related disorders. The mechanisms, potential targets and experimental models of S. baicalensis root for ameliorating pregnancy-related diseases, such as recurrent spontaneous abortion, preeclampsia, preterm birth, fetal growth restriction and gestational diabetes mellitus, are highlighted.

Doppler evaluation of normal and abnormal placenta

Doppler techniques are needed for the evaluation of the intraplacental circulation and can be of great value in the diagnosis of placental anomalies. Highly sensitive Doppler techniques can differentiate between the maternal (spiral arteries) and fetal (intraplacental branches of the umbilical artery) components of the placental circulation and assist in the evaluation of the placental functional units. A reduced number of placental functional units can be associated with obstetric complications, such as fetal growth restriction. Doppler techniques can also provide information on decidual vessels and blood movement. Abnormal decidual circulation increases the risk of placenta accreta. Doppler evaluation of the placenta greatly contributes to the diagnosis and clinical management of placenta accreta, vasa previa, placental infarcts, placental infarction hematoma, maternal floor infarction, massive perivillous fibrin deposition and placental tumors. However, it has a limited role in the diagnosis and clinical management of placental abruption, placental hematomas, placental mesenchymal dysplasia and mapping of placental anastomoses in monochorionic twin pregnancies. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Intraplacental Villous Artery Doppler as an Independent Predictor for Placenta-Mediated Disease and Its Comparison with Uterine Artery Doppler and/or Placental Biochemical Markers in Predictive Models: A Prospective Cohort Study

OBJECTIVES

To validate intraplacental villous artery (IPVA) Doppler as a predictor for placenta-mediated diseases (PMDs), to compare its predictive value with uterine artery (UtA) Doppler and placental biochemical markers, and to assess its value in predictive PMD models.

METHODS

IPVA and UtA indices (pulsatility index [PI] and resistance index [RI]) were recorded at 18-24 weeks of gestation in a cohort of 117 women. The predictive values of IPVA, UtA, and placental biochemical markers were analyzed and compared between the PMD group (the women who developed preeclampsia or intrauterine growth restriction) and the non-PMD group (the women who remained healthy throughout pregnancy and 3 months postpartum) using the receiver-operating characteristic curves. Logistic regression was used to compare predictive models for PMDs based on IPVA, UtA, and/or biochemical markers.

RESULTS

31 (26.5%) women developed PMD (17 preeclampsia and 14 intrauterine growth restriction). IPVA PI was significantly higher in the PMD group than in the non-PMD group (p = 0.001). UtA PI and RI values remained nonsignificant between both groups (p = 0.066 and 0.104, respectively). IPVA PI from the 3 main branches of the placenta, and specifically the central main stem villi, showed a strong association with PMDs in comparison to UtA (p = 0.03 and 0.001 vs. 0.29). Model prediction including IPVA and UtA PI with or without placental biomarkers did not add any further significance to IPVA PI alone (p = 0.03, 0.41, and 0.36).

CONCLUSIONS

IPVA PI appears superior to UtA PI or RI and placental biomarkers in PMD prediction. Model prediction for PMDs including IPVA, UtA Doppler, and biochemical markers did not enhance prediction values compared to IPVA Doppler alone.

Placental transcriptional and histologic subtypes of normotensive fetal growth restriction are comparable to preeclampsia

BACKGROUND

Infants born small for gestational age because of pathologic placenta-mediated fetal growth restriction can be difficult to distinguish from those who are constitutionally small. Additionally, even among fetal growth-restricted pregnancies with evident placental disease, considerable heterogeneity in clinical outcomes and long-term consequences has been observed. Gene expression studies of fetal growth-restricted placentas also have limited consistency in their findings, which is likely due to the presence of different molecular subtypes of disease. In our previous study on preeclampsia, another heterogeneous placenta-centric disorder of pregnancy, we found that, by clustering placentas based only on their gene expression profiles, multiple subtypes of preeclampsia, including several with co-occurring suspected fetal growth restriction, could be identified.

OBJECTIVE

The purpose of this study was to discover placental subtypes of normotensive small-for-gestational-age pregnancies with suspected fetal growth restriction through the use of unsupervised clustering of placental gene expression data and to investigate their relationships with hypertensive suspected fetal growth-restricted placental subtypes.

STUDY DESIGN

A new dataset of 20 placentas from normotensive small-for-gestational-age pregnancies (birthweight <10th percentile for gestational age and sex) with suspected fetal growth restriction (ultrasound features of placental insufficiency) underwent genome-wide messenger RNA expression assessment and blinded detailed histopathologic evaluation. These samples were then combined with a subset of samples from our previously published preeclampsia cohort (n=77) to form an aggregate fetal growth-focused cohort (n=97) of placentas from normotensive small-for-gestational-age, hypertensive (preeclampsia and chronic hypertensive) small-for-gestational-age, and normotensive average-for-gestational-age pregnancies. Gene expression data were subjected to unsupervised clustering, and clinical and histopathologic features were correlated to the identified sample clusters.

RESULTS

Clustering of the aggregate dataset revealed 3 transcriptional subtypes of placentas from normotensive small-for-gestational-age/suspected fetal growth-restricted pregnancies, with differential enrichment of clinical and histopathologic findings. The first subtype exhibited either no placental disease or mild maternal vascular malperfusion lesions, and, co-clustered with the healthy average-for-gestational-age control subjects; the second subtype showed more severe evidence of hypoxic damage and lesions of maternal vascular malperfusion, and the third subtype demonstrated an immune/inflammatory response and histologic features of a maternal-fetal interface disturbance. Furthermore, all 3 of these normotensive small-for-gestational-age subtypes co-clustered with a group of placentas from hypertensive small-for-gestational-age pregnancies with more severe clinical outcomes, but very comparable transcriptional and histologic placental profiles.

CONCLUSION

Overall, this study provides evidence for at least 2 pathologic placental causes of normotensive small-for-gestational-age, likely representing true fetal growth restriction. These subtypes also show considerable similarity in gene expression and histopathology to our previously identified "canonical" and "immunologic" preeclampsia placental subtypes. Furthermore, we discovered a subtype of normotensive small-for-gestational-age (with suspected fetal growth restriction) with minimal placental disease that may represent both constitutionally small infants and mild fetal growth restriction, although these cannot be distinguished with the currently available data. Future work that focuses on the identification of etiology-driven biomarkers and therapeutic interventions for each subtype of fetal growth restriction is warranted.

Ultrasound detection of altered placental vascular morphology based on hemodynamic pulse wave reflection

Abnormally pulsatile umbilical artery (UA) Doppler ultrasound velocity waveforms are a hallmark of severe or early onset placental-mediated intrauterine growth restriction (IUGR), whereas milder late onset IUGR pregnancies typically have normal UA pulsatility. The diagnostic utility of these waveforms to detect placental pathology is thus limited and hampered by factors outside of the placental circulation, including fetal cardiac output. In view of these limitations, we hypothesized that these Doppler waveforms could be more clearly understood as a reflection phenomenon and that a reflected pulse pressure wave is present in the UA that originates from the placenta and propagates backward along the UA. To investigate this, we developed a new ultrasound approach to isolate that portion of the UA Doppler waveform that arises from a pulse pressure wave propagating backward along the UA. Ultrasound measurements of UA lumen diameter and flow waveforms were used to decompose the observed flow waveform into its forward and reflected components. Evaluation of CD1 and C57BL/6 mice at embryonic day (E)15.5 and E17.5 demonstrated that the reflected waveforms diverged between the strains at E17.5, mirroring known changes in the fractal geometry of fetoplacental arteries at these ages. These experiments demonstrate the feasibility of noninvasively measuring wave reflections that originate from the fetoplacental circulation. The observed reflections were consistent with theoretical predictions based on the area ratio of parent to daughters at bifurcations in fetoplacental arteries suggesting that this approach could be used in the diagnosis of fetoplacental vascular pathology that is prevalent in human IUGR. Given that the proposed measurements represent a subset of those currently used in human fetal surveillance, the adaptation of this technology could extend the diagnostic utility of Doppler ultrasound in the detection of placental vascular pathologies that cause IUGR.NEW & NOTEWORTHY Here, we describe a novel approach to noninvasively detect microvascular changes in the fetoplacental circulation using ultrasound. The technique is based on detecting reflection pulse pressure waves that travel along the umbilical artery. Using a proof-of-principle study, we demonstrate the feasibility of the technique in two strains of experimental mice.