Uterine artery Doppler in high-risk pregnancies at 23-24 gestational weeks is of value in predicting adverse outcome of pregnancy and selecting cases for more intense surveillance

The role of second trimester uterine artery doppler using uterine artery score in routine prenatal care in Switzerland

OBJECTIVE

The role of 2nd trimester uterine artery Doppler (UtAd) remains unclear and its implementation varies greatly. Aim of this study was to determine whether 2nd trimester UtAd interpreted with uterine artery score (UAS), a score combining PI and notching in both UtA, is useful in an unselected population in routine care.

METHODS

We retrospectively calculated the UAS in 503 unselected singleton pregnancies with 2nd trimester scan at 20-24 weeks between 09/2021 and 08/2023 and later delivery in our department and analysed its relationship with perinatal outcome.

RESULTS

With UAS > 2 there was a significant increase in adverse perinatal outcome such as hypertension/PE (OR 7.88), SGA (OR 6.82), preterm birth (OR 5.51) and placental abruption (OR 6.89). In contrast, no significant difference was found when comparing UAS 0, 1 and 2. In general, NPV for adverse outcomes were high while PPV were low. In 50 % of SGA-fetuses and 33 % of cases with hypertension/PE in UAS 3-4, the woman had no risk factor.

CONCLUSION

Routine 2nd trimester UtAd is useful in all pregnancies as it can identify additional patients without a pre-existing risk who generally would not be eligible for intense surveillance but still develop PE or SGA later. Further, due to the high NPV, UtAd qualifies as a rule-out tool for adverse outcome even in high-risk pregnancies. To standardise its interpretation, UAS with a cut-off at 2 seems to be a suitable tool for an unselected population. In case of UAS 3-4 a more intense surveillance program should be offered.

Prediction by uterine artery Doppler screening of small-for-gestational-age neonates at 19-24 weeks' gestation

OBJECTIVE

Small-for-gestational-age (SGA) neonates are at increased risk of perinatal mortality and morbidity. We aimed to investigate the performance of uterine artery pulsatility index (UtA-PI) at 19-24 weeks' gestation to predict the delivery of a SGA neonate in a Chinese population.

METHODS

This was a retrospective cohort study using data obtained between January 2010 and June 2018. Doppler ultrasonography was performed at 19-24 weeks' gestation. SGA was defined as birth weight below the 10th centile according to the INTERGROWTH-21st fetal growth standards. The performance of UtA-PI to predict the delivery of a SGA neonate was assessed using receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

We included 6964 singleton pregnancies, of which 748 (11%) delivered a SGA neonate, including 115 (15%) women with preterm delivery. Increased UtA-PI was associated with an elevated risk of SGA, both in neonates delivered at or after 37 weeks' gestation (term SGA) and those delivered before 37 weeks (preterm SGA). The areas under the ROC curve (AUCs) for UtA-PI were 64.4% (95% CI, 61.5-67.3%) and 75.8% (95% CI, 69.3-82.3%) for term and preterm SGA, respectively. The performance of combined screening by maternal demographic/clinical characteristics and estimated fetal weight in the detection of term and preterm SGA was improved significantly by the addition of UtA-PI, although the increase in AUC was modest (2.4% for term SGA and 4.9% for preterm SGA).

CONCLUSIONS

This is the first Chinese study to evaluate the role of UtA-PI at 19-24 weeks' gestation in the prediction of the delivery of a neonate with SGA. The addition of UtA-PI to traditional risk factors improved the screening performance for SGA, and this improvement was greater in predicting preterm SGA compared with term SGA. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Association Between Serum Matrix Metalloproteinase-2 Levels and Mean Doppler Pulsatility Index of Uterine Arteries in Patients with Preeclampsia

Background: Мatrix metalloproteinase-2 (MMP-2) is an enzye from the gelatinases family involved mainly in collagen degradation. It is also known as a key regulator of normal vascular remodelling during a healthy pregnancy. Failure of regulation of MMP-2 has been associated with abnormal vasodilation, placentation, uterine expansion and development of preeclampsia (PE). Aims: (1) determine serum MMP-2 levels in women with PE and healthy pregnancy, (2) evaluate mean uterine arteries Doppler pulsatility index (UtA PI) and (3) investigate the a possible association between these parameters.

Materials and methods: This was a case-control study. Fifty-five women with PE (mean age 24.9 ± 6 years) and a control group of 35 women with normal pregnancies (mean age 24.7 ± 5.4 years) were examined. An enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of MMP-2. Mean UtA PI were evaluated by Doppler velocimetry.

Results: Serum ММР-2 levels in preeclampsia were significantly higher than in women with normal pregnancy 11.7 (9.1÷15.5) vs. 7.7 ng/ml (6.5÷13.4) (p = 0.016). Mean UtA PI was significantly higher in preeclampsia than in healthy pregnant women: 1.12 (0.82÷1.5) vs. 0.75 (0.69÷0.85); (p = 0.024). ММР-2 correlated with UtA PI (r = 0.214; p = 0.043). Cutoff value at 14 ng/ml for MMP-2 was found to discriminate between PE and healthy pregnancy.

Conclusion: Our data showed an association between serum MMP-2 and Mean UtA PI. We suggest that MMP-2 could have a potential imply on maternal uterine arteries’ structure, favoring their constriction, increased resistance and abnormal uterine vascular remodeling. Further studies are warranted to clarify whether determination of MMP-2 cutoff value might contribute in the diagnosic work-out strategy for PE.

A Review of Roles of Uterine Artery Doppler in Pregnancy Complications

The invasion of trophoblasts into the uterine decidua and decidual vessels is critical for the formation of placenta. The defects of placentation are related to the etiologies of preeclampsia (PE), fetal growth restriction (FGR), and small-for-gestational age (SGA) neonates. It is possible to predict significant vascular events during pregnancy through uterine artery Doppler (UAD). From the implantation stage to the end of pregnancy, detecting changes in uterine and placental blood vessels can provide a favorable diagnostic instrument for pregnancy complications. This review aims to collect literature about the roles of UAD in pregnancy complications. We consider all relevant articles in English from January 1, 1983 to October 30, 2021. Predicting pregnancy complications in advance allows practitioners to carry out timely interventions to avoid or lessen the harm to mothers and neonates. Administering low-dose aspirin daily before 16 weeks of pregnancy can significantly reduce the incidence of pregnancy complications. From early pregnancy to late pregnancy, UAD can combine with other maternal factors, biochemical indicators, and fetal measurement data to identify high-risk population. The identification of high-risk groups can also lessen maternal mortality. Besides, through moderate risk stratification, stringent monitoring for high-risk pregnant women can be implemented, decreasing the incidence of adversities.

Doppler ultrasound in pregnancy - quality requirements of DEGUM and clinical application (part 2)

This second part on Doppler sonography in prenatal medicine and obstetrics reviews its clinical applications. While this has not become the initially anticipated screening tool, it is used for the diagnosis and surveillance of a variety of fetal pathologies. For example, the sonography-based determination of uterine artery blood flow indices is an important parameter for the first trimester multimodal preeclampsia risk assessment, increasing accuracy and providing indication for the prophylactic treatment with aspirin. It also has significant implications for the diagnosis and surveillance of growth-restricted fetuses in the second and third trimesters through Doppler-sonographic analysis of umbilical artery, middle cerebral artery and ductus venosus. Here, especially the hemodynamics of the ductus venosus provides a critical criterium for birth management of severe, early-onset FGR before 34 + 0 weeks of gestation. Further, determination of maximum blood flow velocity of the middle cerebral artery is a central parameter in fetal diagnosis of anemia which has been significantly improved by this analysis. However, it is important to note that the mentioned improvements can only be achieved through highest methodological quality. Importantly, all these analyses are also applied to twins and higher order multiples. Here, for the differential diagnosis of specific complications such as TTTS, TAPS and TRAP, the application of Doppler sonography has become indispensable. To conclude, the successful application of Doppler sonography requires both exact methodology and precise pathophysiological interpretation of the data.

Failure of Decidualization and Maternal Immune Tolerance Underlies Uterovascular Resistance in Intra Uterine Growth Restriction

Failure of uterine vascular transformation is associated with pregnancy complications including Intra Uterine Growth Restriction (IUGR). The decidua and its immune cell populations play a key role in the earliest stages of this process. Here we investigate the hypothesis that abnormal decidualization and failure of maternal immune tolerance in the second trimester may underlie the uteroplacental pathology of IUGR. Placental bed biopsies were obtained from women undergoing elective caesarian delivery of a healthy term pregnancy, an IUGR pregnancy or a pregnancy complicated by both IUGR and preeclampsia. Decidual tissues were also collected from second trimester terminations from women with either normal or high uterine artery Doppler pulsatile index (PI). Immunohistochemical image analysis and flow cytometry were used to quantify vascular remodeling, decidual leukocytes and decidual status in cases vs. controls. Biopsies from pregnancies complicated by severe IUGR with a high uterine artery pulsatile index (PI) displayed a lack of: myometrial vascular transformation, interstitial, and endovascular extravillous trophoblast (EVT) invasion, and a lower number of maternal leukocytes. Apoptotic mural EVT were observed in association with mature dendritic cells and T cells in the IUGR samples. Second trimester pregnancies with high uterine artery PI displayed a higher incidence of small for gestational age fetuses; a skewed decidual immunology with higher numbers of; CD8 T cells, mature CD83 dendritic cells and lymphatic vessels that were packed with decidual leukocytes. The decidual stromal cells (DSCs) failed to differentiate into the large secretory DSC in these cases, remaining small and cuboidal and expressing lower levels of the nuclear progesterone receptor isoform B, and DSC markers Insulin Growth Factor Binding protein-1 (IGFBP-1) and CD10 as compared to controls. This study shows that defective progesterone mediated decidualization and a hostile maternal immune response against the invading endovascular EVT contribute to the failure of uterovascular remodeling in IUGR pregnancies.

Doppler evaluation of umbilical artery during normal gestation in sheep

Throughout gestation, changes in foetal umbilical cord Doppler parameters in ewes were detected. Doppler ultrasonography of the umbilical artery was performed weekly starting at 18 weeks before parturition until birth. In the foetal umbilical artery (UA), systolic peak velocity (SPV), end diastolic velocity (EDV), increased (p for within-subjects effect <0.001) while pulsatility index (PI) resistance index (RI) decreased (p for within-subjects effect <0.001) with the progress of pregnancy. A linear trend was found on all patterns (p < 0.001). In particular, the EDV values increased significantly (p < 0.05) with respect to previous weeks, at weeks 16, 11, 10, 7, and 1 before parturition. The SPV values increased significantly (p < 0.05), with respect to previous observations, at weeks 11, 10, and 7 before parturition. Finally, the PI and RI decreased significantly (p < 0.05) only at week 7 before parturition. The increased velocities and reduced resistance index suggest a progressive increment in blood flow to the foetus towards the end of pregnancy. Foetal and utero-placental vascular parameters can be reliably evaluated using high-frequency ultrasound.

Correlation Between Fetal Weight Gain and Birth Weight with Blood Flow in the Uterine Arteries Calculated with the PixelFlux Technique

Introduction

The aim was to investigate correlations between fetal weight gain/day and birthweight with blood flow estimates in the uterine arteries calculated with the PixelFlux technique and with measurements from TAmax. We also aimed to examine the agreement between estimates using the two methods.

Material and methods

We conducted a prospective observational pilot study in pregnancy week 24-25 in women with risk pregnancies referred to the fetal medical centre at St. Olavs Hospital, Trondheim, Norway from March 2016 to June 2016. Blood flow in the uterine arteries was calculated using time-averaged peak velocity (TAmax) and the PixelFlux technique. PixelFlux is a method based on pixelwise calculation of spatially angle-corrected velocities and areas of all pixels inside a vessel during a heart cycle.

Results

The mean flow calculated from PixelFlux and TAmax was 811 ml/minute and 787 ml/minute, respectively. The intra-class correlation coefficient was 0.83 (95% CI 0.72-0.90) and limits of agreement were -441 ml/minute (95% CI -558 to -324 ml/minute) to 489 ml/minute (95% CI 372 to 606 ml/minute). We observed a significant correlation between mean flow calculated from PixelFlux and birthweight (r=0.41; p<0.01) and between flow calculated from PixelFlux and weight gain/day (r=0.33; p=0.02). Calculation based on TAmax was significant correlated to birthweight (r=0.34; p=0.02), but not to weight-gain/day. Pulsatile index was not correlated to flow, birthweight or fetal weight-gain/day.

Conclusions

We found significant correlations between estimated blood flow in the uterine arteries using the PixelFlux technique with fetal weight-gain/day and with birthweight. Estimates from two methods showed good agreement.

Identification of patients at risk for preeclampsia with the use of uterine artery Doppler velocimetry and copeptin

PURPOSE

To investigate the relationship between maternal copeptin levels and uterine artery Doppler examination and progress of preeclampsia.

MATERIALS AND METHODS

A cross-sectional study was designed with women those were screened at 20 + 0 - 24+  6 weeks' gestation between May 2014 and August 2014. The obstetric records of all normotensive women were examined. Uterine artery Doppler velocimetry results and serum copeptin levels were measured. The patients were divided into two groups according to normal (n = 67) and abnormal uterine artery Doppler (n = 21) findings.

RESULTS

Maternal age was significantly lower in group 1 (n = 21, 23.9%) than in group 2 (n= 67, 76.1%) (p < 0.05). We found no differences in maternal characteristics, birth weight, gestational age at delivery and copeptin levels between the two groups. Maternal serum copeptin levels were higher in women who subsequently developed preeclampsia. There was also a significant correlation between copeptin levels and the presence of preeclampsia. (p = 0.002).

CONCLUSIONS

Copeptin levels are significantly higher in patients who develop preeclampsia.

Predictive accuracy of the first trimester Doppler scan: a meta-study

AIM

To determine sensitivity and cut-off indices of the uterine artery Doppler (UAD) in prediction of preeclampsia and fetal growth restriction (FGR).

METHODS

Seventy-six studies published in 1995-2014, present 298,329 prenatal Doppler screenings performed in nullipara in the first and early second trimesters of singleton pregnancies. The sample is stratified into four groups based on the Doppler sensitivity and specificity indices pertaining to the major clinical endpoints of the cohort.

RESULTS

The FGR diagnostic specificity (r = 0.728) and bilateral notching index (r = 0.803) correlations indicate that the UAD accuracy depends on the placental bed and the screening mode.

CONCLUSIONS

Predictive sensitivity of the UAD increases after 16 weeks + 3 days (115 days) of gestation. The best predictive parameter of preeclampsia and FGR is the placental side uterine artery resistance index which confers to the highest means when the placenta is on the midline (OR 0.9).