Mean Uterine Artery Resistance Index Research Articles

Influence of genetic variants for birth weight on fetal growth and placental haemodynamics

ObjectiveTo determine the combined effect of 60 genetic variants (single nucleotide polymorphisms, SNPs), previously identified as being associated with birth weight, on fetal growth and placental haemodynamics throughout pregnancy.DesignProspective birth...

804: eFGR prevalence, prognosis and outcomes in a UK population dataset

Extremely early onset fetal growth restriction (eFGR; FGR < 3rd centile diagnosed prior to 28 weeks’ gestation, delivered prior to 33 weeks’ gestation) is a rare, but devastating pregnancy complication. Relatively little is known about its prevalence and prognosis, complicating counselling and management. In this study we have examined eFGR using a large national dataset combined with detailed fetal medicine measurements. Scottish national health service data (333,213 births from 2012-2017) was used to retrospectively determine prevalence and survival in eFGR. Prognostic information was derived from a single fetal medicine database of eFGR cases (n=183). Potential prognostic indicators of fetal death in-utero (FDIU) including presenting characteristics and longitudinal growth velocity were examined using logistic and mixed level regression. eFGR prevalence is 3 per 1000 pregnancies. Survival was >75% for those born after 29 weeks, and at a birthweight above 800g. Using the detailed eFGR database, sonographic factors predictive of FDIU at diagnosis (adjusted for gestation) included estimated fetal weight (EFW) (25g increment: aOR 0.71 (95% confidence interval 0.62-0.81)), umbilical artery end-diastolic flow (present compared to absent/reversed: 13.4 (3.70-48.6)) and mean uterine artery resistance index (0.1 increment: 2.05 (1.23-3.43)). A multivariate prognostic model using these factors correctly identified 43/45 cases of FDIU, with a positive likelihood ratio (LR) of 4.4 but a negative LR of 0.09. Growth velocity in pregnancies ending in FDIU was significantly slower (Figure 1), with a 50g/week increase in EFW between 24-26 weeks’ gestation associated with a 53% reduction in FDIU. This is the largest single study to date of eFGR prognosis prediction, and the first to determine eFGR prevalence in a population dataset. We have identified factors predictive of FDIU and proposed a potential model to use in clinical care which, due to its strong negative LR, would allow clinicians to reassure those with a normal result that pregnancy is likely to result in a live birth.

Maternal uterine artery Doppler in the first and second trimesters as screening method for hypertensive disorders and adverse perinatal outcomes in low-risk pregnancies.

ObjectiveTo assess the maternal demographic characteristics and uterine artery (UA) Doppler parameters at first and second trimesters of pregnancy as predictors for hypertensive disorders (HDs) and adverse perinatal outcomes.MethodsThis prospective cohort study comprised 162 singleton low-risk women undergoing routine antenatal care. The left and right UA were assessed by color and pulsed Doppler and the mean pulsatility and resistance indices as well as the presence of a bilateral protodiastolic notch were recorded at 11 to 14 and 20 to 24 weeks' gestation. Multilevel regression analysis was used to determine the effects of maternal characteristics and abnormal UA Doppler parameters on the incidence of HD, small for gestational age newborn, cesarean section rate, Apgar score <7 at 1st and 5th minute, and admission to the neonatal intensive care unit.ResultsFifteen women (9.2%) developed HD. UA mean resistance index (RI), UA mean pulsatility index, and parity were independent predictors of HD. Compared to the pregnancies with a normal UA mean RI at the first and second trimesters, pregnancies with UA mean RI >95th percentile only at the first trimester showed an increased risk for HD (odds ratio, 23.25; 95% confidence interval, 3.47 to 155.73; P<0.01). Similar result was found for UA mean pulsatility index >95th percentile (odds ratio, 9.84; 95% confidence interval, 1.05 to 92.10; P=0.05). The model including maternal age, maternal and paternal ethnicity, occupation, parity and UA mean RI increased the relative risk for HD (area under receiver operating characteristics, 0.81).ConclusionA first-trimester screening combining maternal characteristics and UA Doppler parameters is useful to predict HD in a low-risk population.

Periconceptional multiple-micronutrient supplementation and placental function in rural Gambian women: a double-blind, randomized, placebo-controlled trial

Background: Maternal micronutrient deficiencies are commonly associated with clinical indicators of placental dysfunction.Objective: We tested the hypothesis that periconceptional multiple-micronutrient supplementation (MMS) affects placental function.Design: We conducted a double-blind, randomized, placebo-controlled trial of MMS in 17- to 45-y-old Gambian women who were menstruating regularly and within the previous 3 mo. Eligible subjects were pre–randomly assigned to supplementation with the UNICEF/WHO/United Nations University multiple micronutrient preparation (UNIMMAP) or placebo on recruitment and until they reached their first antenatal check-up or for 1 y if they failed to conceive. Primary outcome measures were midgestational indexes of utero-placental vascular-endothelial function [ratio of plasminogen-activator inhibitor (PAI) 1 to PAI-2 and mean uterine-artery resistance index (UtARI)] and placental active transport capacity at delivery [fetal to maternal measles antibody (MMA) ratio].Results: We recruited 1156 women who yielded 415 pregnancies, of which 376 met all of the inclusion criteria. With adjustment for gestational age at sampling, there were no differences in PAI-1 to PAI-2 or MMA ratios between trial arms, but there was a 0.02-unit reduction in UtARI between 18 and 32 wk of gestation (95% CI: −0.03, −0.00; P = 0.040) in women taking UNIMMAP.Conclusions: Placental vascular function was modifiable by periconceptional micronutrient supplementation. However, the effect was small and supplementation did not further affect other variables of placental function. This trial was registered at www.controlled-trials.com as ISRCTN 13687662.

Early pregnancy prediction of preeclampsia in nulliparous women, combining clinical risk and biomarkers: the Screening for Pregnancy Endpoints (SCOPE) international cohort study.

More than half of all cases of preeclampsia occur in healthy first-time pregnant women. Our aim was to develop a method to predict those at risk by combining clinical factors and measurements of biomarkers in women recruited to the Screening for Pregnancy Endpoints (SCOPE) study of low-risk nulliparous women. Forty-seven biomarkers identified on the basis of (1) association with preeclampsia, (2) a biological role in placentation, or (3) a role in cellular mechanisms involved in the pathogenesis of preeclampsia were measured in plasma sampled at 14 to 16 weeks' gestation from 5623 women. The cohort was randomly divided into training (n=3747) and validation (n=1876) cohorts. Preeclampsia developed in 278 (4.9%) women, of whom 28 (0.5%) developed early-onset preeclampsia. The final model for the prediction of preeclampsia included placental growth factor, mean arterial pressure, and body mass index at 14 to 16 weeks' gestation, the consumption of ≥3 pieces of fruit per day, and mean uterine artery resistance index. The area under the receiver operator curve (95% confidence interval) for this model in training and validation cohorts was 0.73 (0.70-0.77) and 0.68 (0.63-0.74), respectively. A predictive model of early-onset preeclampsia included angiogenin/placental growth factor as a ratio, mean arterial pressure, any pregnancy loss <10 weeks, and mean uterine artery resistance index (area under the receiver operator curve [95% confidence interval] in training and validation cohorts, 0.89 [0.78-1.0] and 0.78 [0.58-0.99], respectively). Neither model included pregnancy-associated plasma protein A, previously reported to predict preeclampsia in populations of mixed parity and risk. In nulliparous women, combining multiple biomarkers and clinical data provided modest prediction of preeclampsia.

Uterine artery Doppler, birth weight and timing of onset of pre-eclampsia: providing insights into the dual etiology of late-onset pre-eclampsia

To investigate the relationship between uterine artery Doppler ultrasound indices and birth weight in women with early-, intermediate- and late-onset pre-eclampsia as compared with women with uneventful pregnancy outcome. In a retrospective, observational cohort study, uterine artery Doppler assessment was carried out at 18+0 to 23+6 weeks' gestation in 26,893 women attending for routine antenatal care in a tertiary care center. The mean resistance index (RI) and its relationship to the outcome of pregnancy and birth-weight centiles were evaluated. Uterine artery RI showed a significant, negative correlation with birth weight (r= -0.20, P<0.0001). Patients with early-onset pre-eclampsia had an increased prevalence of high uterine artery mean RI, above the 90(th) centile, corresponding to an increased proportion of small-for-gestational age (SGA) neonates with a birth weight below the 10(th) centile. In late-onset pre-eclampsia, however, there was an unexpectedly higher proportion of large-for-gestational-age (LGA) neonates with a birth weight above the 90(th) centile without a concurrent increase in the prevalence of low uterine artery mean RI below the 10(th) centile. The finding of a bimodal skewed distribution of birth weight, with neonates exhibiting a higher prevalence of both LGA and SGA with late-onset pre-eclampsia, indicates that there are two types of late-onset pre-eclampsia. These findings explain the poor performance of mid-trimester uterine artery Doppler in predicting pre-eclampsia at term and provide insights into the placental origins of the early and late forms of pre-eclampsia.

Reference range of uterine artery Doppler parameters between the 11th and 14th pregnancy weeks in a population sample from Northeast Brazil

To establish reference values for the first trimester uterine artery resistance index (UtA-RI) and pulsatility index (UtA-PI) in healthy singleton pregnant women from Northeast Brazil. A prospective observational cohort study including 409 consecutive singleton pregnancies undergoing routine early ultrasound screening at 11 - 14 weeks of gestation was performed. The patients responded to a questionnaire to assess maternal epidemiological characteristics. The left and right UtA-PI and UtA-RI were examined by color and pulsed Doppler by transabdominal technique and the mean UtA-PI, mean UtA-RI and the presence of bilateral protodiastolic notching were recorded. Quartile regression was used to estimate reference values. The mean ± standard deviation UtA-RI and UtA-PI were 0.7 ± 0.1 and 1.5 ± 0.5, respectively. When segregated for gestation age, mean UtA-PI was 1.6 ± 0.5 at 11 weeks, 1.5 ± 0.6 at 12 weeks, 1.4 ± 0.4 at 13 weeks and 1.3 ± 0.4 at 14 weeks' gestation and mean UtA-RI was 0.7 ± 0.1 at 11 weeks, 0.7 ± 0.1 at 12 weeks, 0.6 ± 0.1 at 13 weeks and 0.6 ± 0.1 at 14 weeks' gestation. Uterine artery bilateral notch was present in 261 (63.8%) patients. We observed that the 5th and 95th percentiles of the UtA-PI and UtA-RI uterine arteries were 0.7 and 2.3 and, 0.5 and 0.8, respectively. Normal reference range of uterine artery Doppler in healthy singleton pregnancies from Northeast Brazil was established. The 95th percentile of UtA-PI and UtA-RI values may serve as a cut-off for future prediction of pregnancy complications studies (i.e., pre-eclampsia) in Northeast Brazil.

Uterine artery resistance index in first trimester and maternal neonatal outcome

ObjectiveTo study the uterine blood flow in early pregnancy, which might provide information about maternal neonatal outcome. MethodsPilot study was undertaken by measuring uterine artery resistance index (UARI) at (10±2) weeks. ResultsOf study subjects 801 primigravida without past, present obstetric disorder, 307 (38.3%) had mean UARI above 95th centile, 494 (61.7%) below 5th centile. Mean UARI above 95th centile of women had pregnancy problems (foetal growth restriction, hypertensive disorders, placental abruption, oligohydramnios) compared to below 5th centile. Of 307 women with mean UARI above 95th percentile, hypertensive disorders occurred in 53 (17.3%) and 21 (40%) with foetal growth restriction. Of 494 with mean UARI below 5th percentile, 30 (6.1%) developed hypertensive disorders (P<0.00006), 4 (13.3%) had FGR (P<0.00006). Placental abruption, occurred in 37 (7.48%) and in 10 (2.02%) with mean UARI above 95th percentile and below 5th percentile (P<0.001) respectively. There were 143 caesarean births, statistically significantly more for foetal distress in with UARI above 95th percentile. With mean UARI above 95th centile, 296 (96.41%) had term, 11 (3.58%) preterm births. Of 67 (21.82%) caesarean births at term, 17 (25.4%) were for foetal distress, with mean UARI below 5th centile, 487 (98.58%) had term births. ConclusionsWomen with higher UARI in first trimester had more often hypertensive disorders, placental abruption, oligohydramnios, caesarean births and foetal distress.

Assessment of uterine artery and aortic isthmus Doppler recordings as predictors of necrotizing enterocolitis

The purpose of this study was to evaluate whether changes of uterine arteries and aortic isthmus Doppler blood flow recordings could enhance the prediction of necrotizing enterocolitis. Doppler characteristics of the uterine artery, umbilical and middle cerebral arteries, ductus venosus, and aortic isthmus were reviewed in 123 growth-restricted fetuses who were then divided into 2 groups: with and without necrotizing enterocolitis. Twelve of 123 newborn infants (9%) expressed necrotizing enterocolitis. This group showed significant association between necrotizing enterocolitis and bilateral notching on the uterine artery (83.3% vs 29.7%; P < .001), uterine artery mean resistance index (83.3% vs 36.9%; P < .002), aortic isthmus diastolic blood flow velocity integrals (Z score: -7.32 vs -3.99; P = .028), and absent or negative "a" wave on the ductus venosus (17% vs 1.8%; P = .021). With the use of logistic regression, uterine bilateral notching could predict necrotizing enterocolitis with a sensitivity of 83.3% and a specificity of 70.3%. More than any other variable, uterine bilateral notching should be recognized as a strong risk factor for necrotizing enterocolitis.

Relation between utero‐placental and feto‐placental circulations: a longitudinal study

To explore the relation between total utero-placental (TQ(uta)) and feto-placental (Q(uv)) blood flows and establish longitudinal reference ranges for the TQ(uta)/Q(uv) ratio and the mean uterine artery and umbilical artery pulsatility (UtaPI/UAPI) and resistance index (UtaRI/UARI) ratios. Prospective longitudinal observational study. University hospital in Norway. Fifty-three low-risk pregnant women. Uterine artery and umbilical vein blood flow was measured using Doppler ultrasonography at 4-weekly intervals from 22(+0) to 39(+6) weeks of gestation. Ratios between utero-placental and feto-placental volume blood flows and between indices of uterine and umbilical artery impedance. The TQ(uta)/Q(uv) ratio had a significant association with the gestational age (p < 0.00001) and decreased with advancing gestation during the second half of pregnancy. The mean UtaPI/UAPI (p = 0.094) and mean UtaRI/UARI (p = 0.323) ratios were not significantly associated with gestational age and remained relatively constant. There was no significant association between TQ(uta) and Q(uv) (p = 0.72), mean UtaPI and UAPI (p = 0.56), or mean UtaRI and UARI (p = 0.57). The gestational-age-related changes in the utero-placental and feto-placental circulations do not appear to be affected by each other under physiological conditions. We have established longitudinal reference ranges for the utero-placental and feto-placental blood flow and impedance ratios during the second half of pregnancy.

Early-Pregnancy Multiple Serum Markers and Second-Trimester Uterine Artery Doppler in Predicting Preeclampsia

To estimate the ability of maternal serum markers and uterine artery Doppler in predicting preeclampsia. In this nested case-control study, maternal serum concentrations of cystatin C, beta2-microglobulin, serum amyloid A, C-reactive protein (CRP), and neopterin were measured, and resistance index of uterine artery blood flow was assessed in 45 women in whom preeclampsia subsequently developed and in 125 women with normal pregnancy outcome. Univariable regression analysis was performed to estimate correlations between serum markers and resistance index for the development of preeclampsia. Significant variables were identified using multiple logistic regressions. Maternal serum markers were measured at a median gestational age of 14.7 weeks (interquartile range 3.1) in control group members and 16.3 weeks (interquartile range 4.8) in the case group members, and uterine resistance index was measured at the second-trimester scan. Univariable logistic regression showed that women with subsequent preeclampsia had increased levels of cystatin C, beta2-microglobulin, neopterin, CRP, and resistance index. Cystatin C, CRP, and resistance index remained independently associated with preeclampsia when multiple logistic regression was applied. Receiver-operating characteristic curve analysis showed that a combination of markers had a better area under the curve (AUC; 0.825) than when used in isolation (cystatin C, AUC 0.725; CRP, AUC 0.634; resistance index, AUC 0.728). Sensitivity of uterine artery resistance index, cystatin C, and CRP combined for predicting preeclampsia was 69.2% for a screen-positive rate of 15%. Maternal serum cystatin C, CRP, and uterine artery mean resistance index are independent predictors of preeclampsia. There is improved prediction of preeclampsia when serum markers are combined with Doppler indices.

Patterns of Change in Uterine Artery Doppler Studies Between 20 and 24 Weeks of Gestation and Pregnancy Outcomes

OBJECTIVES: To describe changes in mean uterine artery resistance index and bilateral notches between 20 and 24 weeks of gestation in healthy nulliparous women and to relate these changes to pregnancy outcome. METHODS: A total of 2,189 nulliparous participants in the Screening for Pregnancy Endpoints study had pregnancy outcomes compared between four uterine artery Doppler groups: normal at 20 and 24 weeks of gestation (group 1), normal at 20 weeks and abnormal at 24 weeks (group 2), abnormal at 20 weeks and normal at 24 weeks (group 3), and abnormal at both 20 and 24 weeks (group 4). Abnormal uterine Doppler was defined as 1) mean resistance index greater than the 90th centile; 2) bilateral notches; and 3) a combination of 1, 2, or both. The main outcomes were preeclampsia and small for gestational age (SGA) neonates (less than the 10th customized centile). RESULTS: Preeclampsia developed in 116 (5.3%) women, and 223 (10.2%) delivered SGA neonates. With abnormal Doppler defined as mean resistance index greater than the 90th centile, the rate of SGA increased across Doppler groups: group 1, 156 (8.4%); group 2, 13 (11%); group 3, 25 (19.5%); and group 4, 29 (35.4%) (P<.001). The rate of SGA was higher in group 3 compared with group 1. Preeclampsia differed among groups 1 (85 [4.6%]), 2 (9 [7.6%], 3 (7 [5.5%]), and 4 (15 [18.3%]) (P<.001). CONCLUSION: Pregnancy outcomes in women with abnormal uterine artery Doppler results at either 20 or 24 weeks were intermediate between those with normal or abnormal results at both time points. If overall test performance could be enhanced by the addition of clinical data, biomarkers, or both, we would recommend that 20 weeks is the most appropriate gestation in the second trimester to perform uterine artery Doppler studies.

Patterns of Change in Uterine Artery Doppler Studies Between 20 and 24 Weeks of Gestation and Pregnancy Outcomes

To describe changes in mean uterine artery resistance index and bilateral notches between 20 and 24 weeks of gestation in healthy nulliparous women and to relate these changes to pregnancy outcome. A total of 2,189 nulliparous participants in the Screening for Pregnancy Endpoints study had pregnancy outcomes compared between four uterine artery Doppler groups: normal at 20 and 24 weeks of gestation (group 1), normal at 20 weeks and abnormal at 24 weeks (group 2), abnormal at 20 weeks and normal at 24 weeks (group 3), and abnormal at both 20 and 24 weeks (group 4). Abnormal uterine Doppler was defined as 1) mean resistance index greater than the 90th centile; 2) bilateral notches; and 3) a combination of 1, 2, or both. The main outcomes were preeclampsia and small for gestational age (SGA) neonates (less than the 10th customized centile). Preeclampsia developed in 116 (5.3%) women, and 223 (10.2%) delivered SGA neonates. With abnormal Doppler defined as mean resistance index greater than the 90th centile, the rate of SGA increased across Doppler groups: group 1, 156 (8.4%); group 2, 13 (11%); group 3, 25 (19.5%); and group 4, 29 (35.4%) (P<.001). The rate of SGA was higher in group 3 compared with group 1. Preeclampsia differed among groups 1 (85 [4.6%]), 2 (9 [7.6%], 3 (7 [5.5%]), and 4 (15 [18.3%]) (P<.001). Pregnancy outcomes in women with abnormal uterine artery Doppler results at either 20 or 24 weeks were intermediate between those with normal or abnormal results at both time points. If overall test performance could be enhanced by the addition of clinical data, biomarkers, or both, we would recommend that 20 weeks is the most appropriate gestation in the second trimester to perform uterine artery Doppler studies. II.

First trimester uterine artery Doppler in women with previous pre‐eclampsia

To assess the role of first trimester uterine artery Doppler in pregnancies previously complicated by pre-eclampsia. Case-control study in two tertiary referral hospitals. A total of 56 singleton pregnancies in women with a previous pregnancy complicated by pre-eclampsia (Group 1). For each case, two parous controls (Group 2) and two nulliparous controls (Group 3) with normal pregnancy outcome were matched. Doppler examination of the uterine arteries at 11-14 weeks' gestation. Mean uterine artery resistance index (UtARI) and notching. Pregnancy outcome. UtARI did not vary significantly between the three groups (0.73, 0.70 and 0.71, respectively). Women in Group 1 had a significantly higher prevalence of uterine artery notching than those in Group 2 (73 vs 57%, p=0.04). In Group 1, the UtARI and prevalence of notching was not significantly increased when pregnancies were subsequently complicated by pre-eclampsia (p=0.60 and 0.61, respectively). However, in 12 pregnancies requiring delivery before 37 weeks due to pre-eclampsia, fetal growth restriction, abruption or intrauterine fetal death, the UtARI was significantly higher than in the 44 pregnancies with normal outcome (p=0.04). A combination of UtARI and notching showed sensitivities up to 75% and negative predictive values up to 88% for adverse outcome before 37 weeks. In pregnancies following a previous gestation complicated by pre-eclampsia, first trimester uterine artery Doppler findings are similar to those observed in nulliparous women. In these high-risk women, a combination of UtARI and notching can predict the risk of adverse outcome before 37 weeks.

First‐trimester uterine artery Doppler indices in term and preterm pre‐eclampsia

To assess the relationship between first-trimester uterine artery Doppler measurements and the development of term and preterm pre-eclampsia. This prospective study of uterine artery Doppler findings at 11-14 weeks in 3058 singleton pregnancies included 57 and 33 cases of term and preterm pre-eclampsia, respectively. The first-trimester uterine artery resistance index (RI) was significantly higher in women who subsequently developed preterm pre-eclampsia (mean RI, 0.79) than in those with a normal outcome (mean RI, 0.70; P = 0.0001) or those who developed pre-eclampsia at term (mean RI, 0.72; P = 0.002). There were no significant differences in first-trimester mean uterine artery RI (P = 0.136) or prevalence of bilateral notches (P = 0.459) between women who had a normal pregnancy outcome and those who developed pre-eclampsia at term. The receiver-operating characteristics curves for the prediction of term and preterm pre-eclampsia by uterine artery Doppler imaging demonstrated a significant association with development of preterm pre-eclampsia (P = 0.0001; area under the curve (AUC), 0.76; 95% CI, 0.66-0.86) but not term pre-eclampsia (P = 0.25; AUC, 0.54; 95% CI, 0.46-0.63). The uterine artery Doppler data in this study suggest that preterm pre-eclampsia is strongly associated with defective invasion of the spiral arteries, in contrast to the findings in term pre-eclampsia which may be a consequence of placental deterioration at term. Our study findings support, but do not prove, a rigid separation between the etiology of early- and late-onset pre-eclampsia. Although there is a strong relationship between first-trimester uterine artery Doppler indices and the subsequent development of preterm pre-eclampsia, our data do not support its routine introduction into clinical practice.

First‐trimester uterine artery Doppler and spontaneous preterm delivery

To assess the relationship between first-trimester uterine artery Doppler measurements and spontaneous preterm delivery. This was a retrospective analysis of uterine artery Doppler findings at 11-14 weeks in 73 singleton pregnancies with spontaneous preterm labor and 2417 pregnancies delivered at term. The uterine artery mean resistance index (RI) was 0.68 (coefficient of variation 19%) and 0.69 (17%) in the preterm and term delivery groups, respectively (P = 0.35). The mean pulsatility index (PI) was 1.42 (39%) and 1.42 (46%) in the term and preterm delivery groups, respectively (P = 0.95). Bilateral diastolic notches were present in 34% of preterm deliveries and 33% of controls (P = 0.84). Restricting the analysis to the 19 pregnancies with preterm delivery before 34 weeks of gestation, no significant difference from controls was observed for RI (mean 0.71, coefficient of variation 11%, P = 0.41), PI (mean 1.56, coefficient of variation 29%, P = 0.27) or the number of bilateral notches (42%, P = 0.41). Despite pathological evidence suggesting that defective placentation is associated with spontaneous preterm delivery, first trimester uterine artery resistance, as assessed by Doppler ultrasound investigation, is not different in pregnancies subsequently complicated by preterm labor compared to pregnancies delivered at term. This finding may be explained by a late failure of trophoblast development in cases destined to deliver preterm.

Correlation between first-trimester uterine artery Doppler indices and maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein A

To assess the correlation between first-trimester uterine artery Doppler measurements and maternal serum levels of free beta-hCG and pregnancy-associated plasma protein A (PAPP-A). Observational study. Teaching hospital. Four hundred thirty-three women at 10-14 weeks of gestation. Doppler ultrasound of the uterine arteries. Fluorimetric immunoassays for free beta-hCG and PAPP-A. Uterine artery mean resistance index (RI), pulsatility index (PI), and number of early diastolic notches. Maternal serum levels of free beta-hCG and PAPP-A. There were 401 uncomplicated pregnancies. In this group, free beta-hCG and PAPP-A did not significantly correlate with uterine artery RI or PI (r values between -0.089 and 0.029, all nonsignificant). Free beta-hCG and PAPP-A levels did not significantly change with the number of notches. Uterine artery resistance and PAPP-A levels were independently correlated with birth weight. Preliminary evidence suggests that first-trimester uterine artery Doppler measurements do not correlate with maternal serum levels of free beta-hCG and PAPP-A. This may allow their combined use in multivariate screening for pregnancy complications.

First trimester uterine artery Doppler abnormalities predict subsequent intrauterine growth restriction

This study was undertaken to evaluate the association between uterine artery Doppler velocimetry performed between 10 and 14 weeks gestation and intrauterine growth restriction (IUGR). Uterine artery Doppler velocimetry data were collected on 1067 women enrolled in the FASTER trial at the University of Colorado site. The data were analyzed by using univariate and multivariable logistic regression analysis. The uterine artery mean resistance index (RI) for the entire cohort was equal on the right and left sides (0.59 +/- 0.14). Of the 1067 women, 34.2% had unilateral or bilateral diastolic notches, 1 notch was observed in 23.8%, and bilateral notches in 10.4%. Women with a high uterine artery mean RI (> or = 75th percentile) were 5.5 times more likely to have IUGR (95% CI 1.6-18.7). There was no significant relationship between notching and IUGR. Elevated first trimester uterine artery mean RI is significantly associated with IUGR.

Reduced Maternal Plasma Urocortin Concentrations and Impaired Uterine Artery Blood Flow at Human Mid Pregnancy

Urocortin is a placental neuropeptide belonging to the family of corticotropin-releasing factors (CRFs), playing a role in the uteroplacental blood flow regulation through the binding to specific CRF receptors. Since CRF receptors are expressed in the uterine vascular bed of pregnant rats, and because urocortin has a relaxant effect on uterine vasculature, we evaluated mid-gestation plasma urocortin levels in women with impaired blood flow through uterine arteries. Maternal plasma urocortin was assayed by specific radioimmunoassay and uterine artery resistance index (RI) by Doppler evaluation at 22-24 weeks' gestation in 57 healthy pregnant women, of which 29 showed a monolateral or bilateral uterine artery notch. Statistical analysis was performed by one-way analysis of variance (ANOVA), followed by post-hoc Tukey test for multiple comparison and Pearson correlation coefficient test. The mean uterine artery RI was significantly (P <.001) higher in women with a notch than healthy controls. Mean +/- SEM maternal plasma urocortin levels were significantly (P <.001) lower in women with unilateral (52.03 +/- 3.25 pg/mL) or bilateral (47.01 +/- 4.16 pg/mL) uterine artery notch than in healthy control pregnant women (84.01 +/- 3.5 pg/mL). While no difference was found in urocortin levels between patients with unilateral or bilateral uterine artery notch, urocortin concentrations inversely correlated with the mean RI (Pearson r = -0.7318; 95% confidence interval -0.8334 to -0.5822; P <.0001). The present findings suggest that reduced levels of circulating urocortin are associated with increased uterine artery resistances and support the hypothesis that urocortin may regulate uterine artery tone at mid gestation.

Factor II

To evaluate whether the determination of maternal plasma Factor II:C (FII:C) and mean uterine artery resistance index may be useful to early predict pre-eclampsia in patients with gestational hypertension. Prospective study. Consecutive enrollment in a public tertiary clinical care centre. A total of 65 women with gestational hypertension at 24-26 weeks. Measurements of maternal plasma FII:C activity levels, ultrasonographic biometrical parameters and Doppler velocimetry of maternal uterine arteries. The probability of developing pre-eclampsia was the main outcome of the study and it was computed by combining the FII:C and the mean uterine artery resistance index cut-off points, chosen by receiver operating characteristic (ROC) curve analysis. F-II:C activity levels and mean uterine artery resistance index were significantly (both P < 0.01) higher in women who developed pre-eclampsia. A weak, but significant correlation (r = 0.3, P < 0.05) was found between these two parameters. FII:C activity levels at the cut-off value of 136.5% achieved a sensitivity of 61.1% and a specificity of 71.3%, while mean uterine artery resistance index (RI) at the cut-off value of 0.57 showed a sensitivity of 85.7% and a specificity of 90.2% in predicting the onset of pre-eclampsia. When both FII:C and mean uterine RI were over the cut-off points the positive predictive value was of 89%, with a 100% negative predictive value when both were below the cut-off points. F-II:C activity levels and mean uterine artery resistance index determination at mid trimester may improve the prediction of superimposed pre-eclampsia on women with early onset gestational hypertension.