Maternal plasma soluble endoglin at 11-13 weeks' gestation in pre-eclampsia

OBJECTIVES

To examine the performance of screening for pre-eclampsia (PE) by a combination of maternal factors, soluble endoglin (sEng), pregnancy associated plasma protein-A (PAPP-A), placental growth factor (PlGF) and uterine artery lowest pulsatility index (L-PI) at 11-13 weeks' gestation.

METHODS

Uterine artery L-PI, sEng, PAPP-A and PlGF were measured at 11-13 weeks in 90 singleton pregnancies that subsequently developed PE, including 30 that required delivery before 34 weeks (early PE) and 60 with late PE, and 180 unaffected controls. Screening performance for PE by maternal factors, sEng, PAPP-A, PlGF and uterine artery L-PI and their combinations was determined.

RESULTS

In early PE, compared to controls, plasma sEng and uterine L-PI were significantly increased and serum PAPP-A and PlGF were decreased. In late PE, compared to controls, serum PlGF was decreased and uterine L-PI was increased but plasma sEng and serum PAPP-A were not significantly different. In screening for early PE, the detection rate for a 10% false-positive rate was 46.7% for sEng alone and 96.3% for a combination of maternal factors, sEng, PlGF and uterine artery L-PI.

CONCLUSIONS

Effective screening for early PE can be provided by a combination of maternal factors, sEng, PlGF and uterine artery L-PI at 11-13 weeks' gestation.

Effect of antihypertensive therapy with alpha-methyldopa on uterine artery Doppler in pregnancies with hypertensive disorders

OBJECTIVES

Antihypertensive drugs lower blood pressure by direct vascular effects or central vasodilatory mechanisms. Their effect on uterine artery Doppler resistance indices in hypertensive disorders of pregnancy is uncertain. This study aimed to evaluate the impact of antihypertensive therapy with alpha-methyldopa on maternal uterine artery Doppler pulsatility index (PI) and resistance index (RI) in women presenting with hypertensive disorders of pregnancy.

METHODS

This was a cross-sectional study of 51 women with pre-eclampsia, 29 with gestational hypertension and 80 matched normotensive controls. Uterine artery PI and RI were measured at recruitment (between 24 and 40 weeks' gestation) and, in the hypertensive groups, 24-48 h after starting alpha-methyldopa. Differences between mild and severe, and between early- and late-onset pre-eclampsia were compared using the Mann-Whitney test. The Wilcoxon rank sum test was used to compare measurements before and after treatment.

RESULTS

Prior to treatment, uterine artery PI and RI were significantly higher in women with pre-eclampsia compared with those with gestational hypertension and controls (P < 0.0001). The median uterine artery PI multiple of the median (MoM) was significantly higher (P < 0.0001) in early-onset than in late-onset pre-eclampsia (1.83 (range, 0.88-3.65) vs. 1.19 (range, 0.91-1.72)) and in severe compared with mild disease (2.26 (range, 2.02-3.65) vs. 1.29 (range, 0.88-2.9)). Uterine artery PI- and RI-MoMs in both pre-eclampsia and gestational hypertension, before and after 34 weeks' gestation, were not affected by alpha-methyldopa treatment.

CONCLUSIONS

Antihypertensive therapy using alpha-methyldopa in women presenting with hypertensive disorders of pregnancy has no significant effect on uterine artery resistance to blood flow, suggesting that it does not impair uteroplacental circulation in these cases.

Sonographic diagnosis of postpartum pseudoaneurysms of the uterine artery: a report of 2 cases

Two cases of post-partum uterine artery pseudoaneurysm are described, 1 after normal vaginal delivery and the other after Caesarean section. Both cases were complicated by heavy bleeding and treated with catheter embolization. A turbulent arterial-type velocity waveform with high peak velocity and forward end-diastolic flow was registered in the feeding vessel. The peak blood flow velocity was high in both cases. The resistance index in the uterine artery was lower in the affected side of the uterus. Three-dimensional angiosonography was used to calculate the volume of the lesion, demonstrate its shape, and identify the feeding vessel.

Three-dimensional vascular indices calculated using conventional power Doppler and high-definition flow imaging: are there differences?

OBJECTIVE

The purpose of this study was to determine whether there are differences in 3-dimensional (3D) vascular indices when calculated using high-definition flow imaging (HDF) and power Doppler imaging (PD).

METHODS

Twenty-five consecutive asymptomatic premenopausal women (mean age, 31 years; range, 28-33 years) without a history of gynecologic disease who attended routine gynecologic checkups were included in the study. All women had regular menstrual cycles, and none had uterine or myometrial disease detected on basal transvaginal sonography. All women underwent 3D transvaginal sonography. In each patient, a first volume using conventional PD was obtained, immediately followed by a second volume using HDF. Volumes were stored and subsequently analyzed for calculating 3D vascular indices (vascularization index [VI], flow index [FI], and vascularization-flow index [VFI]) from the endometrium.

RESULTS

The median VI, FI, and VFI were significantly higher when calculated using HDF compared with conventional PD (P < .05).

CONCLUSIONS

Three-dimensional vascular indices calculated using HDF are higher than those calculated using conventional PD.

The relationship between unexplained elevated serum markers in triple test, uterine artery Doppler measurements and adverse pregnancy outcome

OBJECTIVE

To investigate the relationship between adverse pregnancy outcomes and unexplained elevations of second trimester maternal serum human chorionic gonadotropin (hCG), alpha fetoprotein (AFP) levels and uterine artery Doppler measurements.

METHODS

A total of 144 women between 16-20 weeks of gestation that applied to our clinic for triple test were enrolled into the study. Study group consisted of 84 pregnant women with hCG and/or AFP levels > or =2 MoM. Control group comprised of 60 pregnant women with hCG and AFP levels <2 MoM. Study group was further subdivided into 3 subgroups: Subgroup I; only AFP> or =2 MoM (n=30), subgroup II; only hCG > or =2 MoM (n=64) and subgroup III; both AFP and hCG > or =2 MoM (n=10).

RESULT

Operative delivery rate (p = 0.0017), overall complication rate (p=0.0002), bilateral early diastolic notch presence rate (p = 0.015) were high and mean birth weight was low (p=0.045) in the study group. In subgroup I patients, low birth weight [LBW] (p = 0.0008), preterm delivery (p = 0.0001), preeclampsia (p = 0.003) and preterm premature rupture of membranes [PPROM] (p = 0.012) rates were high. In subgroup II patients, only small for gestational age baby [SGA] (p = 0.016) rate was high. In subgroup III patients LBW (p = 0.009), preterm delivery (p = 0.0001) and PPROM (p = 0.01) rates were high. According to Doppler velocimetry studies, bilateral early diastolic notch presence rate was high (p = 0.015) in the study group.

CONCLUSION

Patients with high AFP levels and bilateral uterine artery diastolic notch presence, are candidates for pregnancy complications and these groups of patients should be followed up more intensively.

Uterine arteriovenous malformation diagnosed with multislice computed tomography: a case report

BACKGROUND

Arteriovenous malformations (AVMs) of the uterus are extremely rare and occur either in congenital or acquired form. The most common clinical presentation is abnormal uterine bleeding, which may be aggravated by therapeutic curettage.

CASE

A case of uterine AVM diagnosed by means of multislice computed tomography (CT). The 37-year-old woman was admitted to the emergency department complaining of hypermenorrhea that had been occurring for the last 5 years. She had undergone multiple currettages for incomplete abortions in the past. Transabdominal ultrasonography demonstrated thickening of the wall of the uterine corpus with numerous cystic lesions. Dynamic CT and CT angiography were useful for detecting and characterizing the pathology in this case. Numerous anomalous blood vessels communicating with the right and left uterine arteries were found in the wall of the uterus and in the parametrium. Uterine and ovarian arteries were enlarged, with early filling of veins on CT angiography. Whole extent of the vascular abnormality was very well depicted by the CT images and CT angiography. The diagnosis of uterine AVMs was thus made noninvasively.

CONCLUSION

This noninvasive technique elegantly demonstrates the uterine AVMs and should be performed to diagnose and to determine the true extent of the malformation, particularly when Doppler ultrasound is inconclusive.

Plasma soluble endoglin concentration in pre-eclampsia is associated with an increased impedance to flow in the maternal and fetal circulations

OBJECTIVES

To examine the relationship between abnormalities in uterine (UtA) and/or umbilical artery (UA) Doppler velocimetry and maternal plasma concentrations of soluble endoglin (sEng) in patients with pre-eclampsia (PE).

METHODS

A cross-sectional study was conducted in 135 normal pregnant women and 69 patients with PE. Patients with PE were subclassified into four groups: those who had Doppler abnormalities in both the UtA and UA, patients who had Doppler abnormalities in the UtA alone, those who had Doppler abnormalities in the UA alone, and patients without Doppler abnormalities in either vessel. Plasma concentrations of sEng were determined by enzyme-linked immunosorbent assay.

RESULTS

Among patients with PE, those with abnormal UtA and UA Doppler velocimetry had the highest median plasma concentration of sEng compared with any other group (P < 0.001, Kruskal-Wallis test). Women with PE with normal Doppler velocimetry in both vessels had the lowest median plasma concentration of sEng. There was a significant relationship between plasma concentrations of sEng and mean UtA resistance index (Spearman Rho = 0.5, P < 0.001) as well as UA pulsatility index (Spearman Rho = 0.4, P = 0.002). Multiple regression analysis suggested that Doppler abnormalities in the UtA and UA as well as gestational age at blood sampling contributed to plasma sEng concentrations (P < 0.001).

CONCLUSIONS

Abnormalities of impedance to blood flow in the UtA and UA are associated with an excess of sEng in the circulation of mothers with PE. These findings suggest that the 'antiangiogenic state' in PE is partially reflected in abnormalities of Doppler velocimetry.

Flow-mediated dilatation in the differential diagnosis of preeclampsia syndrome

BACKGROUND

The preeclampsia syndrome is associated with endothelial dysfunction and the differential diagnosis between pure preeclampsia (PE) and superimposed preeclampsia (SPE) can be only be attained 12 weeks after delivery.

OBJECTIVE

To compare the assessment of endothelial function through flow-mediated dilatation in pregnant women with pure preeclampsia and superimposed preeclampsia.

METHODS

The flow-mediated dilatation of the brachial artery was carried out according to the recommendations of the International Brachial Artery Reactivity Task Force in pregnant women with preeclampsia syndrome. PE (n=14) and SPE (n=13) were diagnosed in the postpartum period according to the definitions of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy.

RESULTS

The median of the flow-mediated dilatation (FMD) in SPE (6.0%; 1.9-10.3) was decreased in comparison with the PE (13.6%;4.4-17.1), an apparently relevant difference , but not statistically significant (p = 0.08). The FMD < 10% was detected in 30.8% of the PE cases and in 69.2% of the SPE cases (p = 0.057). Significant differences could not be detected in the morphology of the uterine arteries between the PE and SPE cases through the Doppler spectrum.

CONCLUSION

The FMD of the brachial artery of patients with preeclampsia syndrome was not capable of differentiating between PE and SPE. However, the data suggest that SPE is associated with worse endothelial function I comparison to PE.

Longitudinal Doppler measurements of spiral artery blood flow in relation to uterine artery blood flow

OBJECTIVE

The purpose of this study was to examine the longitudinal relationship between Doppler flow velocity waveforms of the spiral artery (SA) and uterine artery (UA) in pregnant women.

METHODS

Ninety-seven primigravidas with uncomplicated singleton pregnancies were analyzed. Spiral artery and combined UA velocity waveforms were assessed by transabdominal color Doppler sonography at gestational ages of 11 through 13, 14 through 17, and 18 through 24 weeks; each measurement was performed twice. The pulsatility index (PI) was calculated for the left and right UA, and the results were averaged as a combined UA. In addition, the presence of UA bilateral notching was reported. Bland-Altman plots and generalized estimating equations were used to assess intraobserver variability and the longitudinal relationship between SA and UA blood velocities.

RESULTS

A total of 284 UA and 263 SA Doppler flow measurements were analyzed. Intraobserver variability rates for the SA and UA were 0.54 and 0.90, respectively. Results showed a continuous decrease of the mean PI in the SA and UA with increasing gestational age. Uterine artery bilateral notching was reported in 35%, 9%, and 3% of the cases at gestational ages of 11 through 13, 14 through 17, and 18 through 24 weeks. Generalized estimating equation analysis showed a significant correlation (r = 0.41) between the SA and UA (P < .0001).

CONCLUSIONS

Uterine artery Doppler measurements in early pregnancy seem to accurately reflect peripheral resistance of SAs. Furthermore, trophoblastic invasion seems a continuous process in the first half of pregnancy, in which early UA bilateral notching is a physiologic event.

A prospective cohort study of the value of maternal plasma concentrations of angiogenic and anti-angiogenic factors in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia

OBJECTIVE

Changes in the maternal plasma concentrations of angiogenic (placental growth factor (PlGF) and vascular endothelial growth factor (VEGF)) and anti-angiogenic factors (sEng and vascular endothelial growth factor receptor-1 (sVEGFR-1)) precede the clinical presentation of preeclampsia. This study was conducted to examine the role of maternal plasma PlGF, sEng, and sVEGFR-1 concentrations in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia.

METHODS

This longitudinal cohort study included 1622 consecutive singleton pregnant women. Plasma samples were obtained in early pregnancy (6-15 weeks) and midtrimester (20-25 weeks). Maternal plasma PlGF, sEng, and sVEGFR-1 concentrations were determined using sensitive and specific immunoassays. The primary outcome was the development of preeclampsia. Secondary outcomes included term, preterm, and early-onset preeclampsia. Receiving operating characteristic curves, sensitivity, specificity, positive and negative likelihood ratios, and multivariable logistic regression were applied. A p-value of <0.05 was considered significant.

RESULTS

(1) The prevalence of preeclampsia, term, preterm, (<37 weeks) and early-onset preeclampsia (<34 weeks) was 3.8 (62/1622), 2.5 (40/1622), 1.4 (22/1622) and 0.6% (9/1622), respectively; (2) Higher likelihood ratios were provided by ratios of midtrimester plasma concentrations of PlGF, sEng, and sVEGFR-1 than single analytes; (3) Individual angiogenic and anti-angiogenic factors did not perform well in the identification of preeclampsia as a whole; in particular, they perform poorly in the prediction of term preeclampsia; (4) In contrast, a combination of these analytes such as the PlGF/sEng ratio, its delta and slope had the best predictive performance with a sensitivity of 100%, a specificity of 98-99%, and likelihood ratios for a positive test of 57.6, 55.6 and 89.6, respectively, for predicting early-onset preeclampsia.

CONCLUSIONS

(1) The PlGF/sEng ratio and its delta and slope had an excellent predictive performance for the prediction of early-onset preeclampsia, with very high likelihood ratios for a positive test result and very low likelihood ratios for a negative test result; and (2) Although the positive likelihood ratios are high and the positive predictive values low, the number of patients needed to be closely followed is 4:1 for the PlGF/sEng ratio and 3:1 for the slope of PlGF/sEng.

Placental size and the prediction of severe early-onset intrauterine growth restriction in women with low pregnancy-associated plasma protein-A

OBJECTIVES

Screening studies for trisomy 21 demonstrate that low maternal serum pregnancy-associated plasma protein-A (PAPP-A) at 11-13 weeks' gestation is associated with stillbirth, intrauterine growth restriction (IUGR) and pre-eclampsia in chromosomally normal fetuses. However, the strength of these associations is too weak to justify screening for these placental insufficiency syndromes. Our objective was to evaluate placental size and uterine artery (UtA) Doppler imaging as second-stage screening tests for women with low PAPP-A.

METHODS

We prospectively studied 90 normal singleton pregnancies with first-trimester PAPP-A </= 0.30 multiples of the median. Maternal serum alpha-fetoprotein (AFP) at 15-18 weeks' gestation, and second-trimester placental size and UtA Doppler indices were assessed as predictors of pregnancy outcome.

RESULTS

The risks of IUGR, preterm delivery before 32 weeks' gestation and stillbirth were significantly associated with small placental size (relative risk (RR), 3.96; 95% CI, 2.21-5.98; RR, 3.96; 95% CI, 2.21-5.98; and RR, 6.44, 95% CI, 2.74-14.54, respectively) and elevated AFP (RR, 3.67; 95% CI, 1.78-7.71; RR, 2.48; 95% CI, 1.23-4.94; and RR, 5.14; 95% CI, 1.66-16.85, respectively), but not with abnormal UtA Doppler indices. The combination of elevated AFP and small placental size further increased the risk of IUGR (RR, 4.88; 95% CI, 2.88-5.31), delivery before 32 weeks' gestation (RR, 4.25; 95% CI, 2.38-4.98) and stillbirth (RR, 7.44; 95% CI, 3.04-3.75).

CONCLUSIONS

Small placental size and elevated AFP, but not UtA Doppler indices, identify women with low PAPP-A at high risk of IUGR, extreme preterm delivery and stillbirth. These additional screening tests may directly improve perinatal outcomes in women with low PAPP-A.

Role of uterine artery Doppler in interpreting low PAPP-A values in first-trimester screening for Down syndrome in pregnancies at high risk of impaired placentation

OBJECTIVES

Low maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) are associated with both increased risk of aneuploidies and impaired trophoblastic invasion, while high uterine artery (UtA) resistance is associated with impaired trophoblastic invasion but not with an increased risk of aneuploidies. The aim of this study was to determine whether high UtA resistance plays a role in explaining low PAPP-A levels in the absence of aneuploidies.

METHODS

This was a prospective study of 116 singleton pregnancies at high risk for impaired placentation (having at least one major risk factor: prior history of pre-eclampsia, pregestational diabetes mellitus, chronic hypertension, chronic kidney disease, body mass index >30, autoimmune disorder, thrombophilia or recurrent pregnancy loss), booked for routine assessment of risk for aneuploidies by means of the first-trimester combined screening test (nuchal translucency thickness (NT) + PAPP-A + beta-human chorionic gonadotropin (beta-hCG)). Measurement of NT and the mean UtA pulsatility index (PI) were carried out at the 11 to 13 + 6-week scan. All values were calculated in multiples of the median (MoM) adjusted for gestational age. A cut-off risk of 1/270 at time of sampling was adopted to differentiate high- from low-risk groups for trisomy 21.

RESULTS

There were 108 patients deemed to be at low risk for trisomy 21 and eight at high risk. None had chromosomal defects, giving a false-positive rate for trisomy 21 of 6.9%. The greatest differences between patients at low risk and those at high risk for trisomy 21 were found in their PAPP-A (0.98 vs. 0.38 MoM, P < 0.01) and beta-hCG (1.09 vs. 1.77 MoM, P = 0.04) values. Greater NT thickness (1.02 vs. 0.90 MoM) and higher mean UtA-PI (1.05 vs. 0.96 MoM) were recorded in the high-risk group, although the differences did not reach statistical significance (P = 0.19 and 0.40, respectively). After log-transformation there were no significant correlations between mean UtA-PI and NT and between mean UtA-PI and beta-hCG. There was a significant negative linear correlation between mean UtA-PI and PAPP-A (r = -0.331; P < 0.01). After adjusting the PAPP-A values by UtA-PI, the false-positive rate for trisomy 21 decreased to 2.6%.

CONCLUSION

Mean UtA-PI at the 11 to 13 + 6-week scan may be an effect-modifier variable for PAPP-A that should be taken into account in the first-trimester combined screening for aneuploidies, at least in pregnancies at high risk for impaired placentation.

First-trimester uterine artery Doppler indices in the prediction of small-for-gestational age pregnancy and intrauterine growth restriction

OBJECTIVES

To assess the relationship of first-trimester uterine artery Doppler indices with subsequent delivery of small-for-gestational age (SGA) neonates or intrauterine growth restriction (IUGR).

METHODS

This was a prospective study in which uterine artery Doppler assessment was performed at 11-14 weeks in 3010 women with singleton pregnancies. Resistance indices (RI) and incidence of bilateral notching were compared between women with normal pregnancies (n = 2445) and those who delivered: SGA neonates (birth weight < 10th centile) (n = 377); SGA neonates who had been affected by pre-eclampsia (n = 27); IUGR neonates (birth weight < 10th centile and abnormal Doppler indices) with delivery > or = 37 weeks (n = 62); and IUGR neonates requiring preterm delivery (delivery < 37 weeks) (n = 36).

RESULTS

The first-trimester uterine artery mean RI and prevalence of bilateral notching were significantly higher in women destined to deliver SGA neonates than in women with normal pregnancies (median uterine artery RI, 0.74 vs. 0.70, P < 0.001; prevalence of bilateral notches, 56% vs. 43%, P < 0.001). The areas under the receiver-operating characteristics curves for the prediction of SGA without pre-eclampsia, IUGR, preterm IUGR and SGA with pre-eclampsia were 0.602, 0.687, 0.776 and 0.708, respectively. There was a statistically significant inverse relationship between mean uterine artery RI and gestational age at delivery in the SGA pregnancies without pre-eclampsia (R = - 0.329, P = 0.01).

CONCLUSIONS

There is a significant relationship between first-trimester uterine artery Doppler RI and the subsequent development of SGA. The sensitivity of first-trimester uterine artery Doppler is greater for SGA with pre-eclampsia than it is for IUGR alone. This could be because these two entities may have different underlying placental abnormalities that are detected variably on first-trimester uterine artery Doppler evaluation.

Mid-trimester maternal serum markers in predicting adverse pregnancy outcome

OBJECTIVE

In a prospective study, we investigated the association between mid-trimester maternal serum AFP (ms-AFP), maternal serum hCG (ms-hCG) levels and adverse pregnancy outcome in a South-Western Greek population.

MATERIALS AND METHODS

126 healthy Greek women with spontaneous pregnancies were investigated for ms-AFP and ms-hCG levels between the 13th and 24th weeks of gestation and followed for adverse pregnancy outcome. Abnormal outcomes were considered as ms-AFP levels or ms-hCG levels > 2.0 multiples of the median value for gestation (MoM). Statistical analysis was performed by Pearson's chi-square test.

RESULTS

Elevated ms-AFP levels were detected in a total of 25 out of the 126 women studied (19.84%). Elevated ms-hCG levels were detected in a total of ten of the 126 women studied (7.93%). Elevated ms-AFP and ms-hCG levels were detected in a total of four of the 126 women studied (3.17%).

CONCLUSION

Multiparameter testing of placental function in the mid-trimester (uterine artery Doppler, placental morphology, ms-AFP and ms-hCG screening) may allow us to identify women with increased risk of developing severe placental insufficiency and pregnancy complications.

[Uterine artery comes directly from ovarine artery: a case report]

The patient is a 48-year-old woman. She came to our hospital because of consistent colporrhagia for one month. Her first menstrual came when she was 17 years old, her last menstrual period (LMP) was on March 23, 2005. When she came to our hospital, she looked weak and anemic. Temperature (T): 36.6 degrees C; pulse(P): 80 counts per minute; respire(R): 19 counts per minute; blood pressure (BP): 130/90 mmHg(1 mmHg=0.133 kPa). Physical examination showed that her vagina was smooth, there was some lifeblood in it; the cervical was hypertrophy; the womb was anteposition; there was no pressure pain; the two side adjuncts were normal. The laboratory examination showed that the white blood cell (WBC) was 3.40 x 10(9)/L the red blood cell (RBC) 3.14 x 10(12)/L the hemoglobin (HGB) 88.0 g/L and the platelet (PLT) 206 x10(9) L. B ultrasound showed that the womb was uniformity aggrandizement. The pathology showed that the endometrium was glandular hyperplasia. The final diagnosis was dysfunction womb hemeorrhage. After the uterine curettage and hormonal regulation, there remained some hemorrhage. The ovarine arterial embolization (OAE) was operated on June 30, 2005. The angiography showed the two side internal lliac arteries had no uterine artery. The two side ovarian arteries were stout. The balance stage showed that the womb's blood supply came from ovarian artery. The consistent colporrhagia stopped after the OAE with gelatin sponge through 3.0F SP microcatheter. After 18 months' follow up survey, the woman's menstrual halted, and she was satisfied with it.

[Normal reference values of the pulsatility index from the uterine and umbilical arteries during pregnancy]

OBJECTIVE

To establish the normal reference values of the pulsatility index in the uterine (UtA PI) and umbilical (UmA PI) arteries during pregnancy.

PATIENTS AND METHODS

A total of 2081 normal pregnancies with normal growth fetuses were evaluated with pulsed Doppler ultrasound (US) between 20 and 40 weeks of gestation (WG). Both, UtA and UmA, were located with color Doppler US and PI measured in 5 consecutive and uniform cardiac cycles. In the uterine arteries, mean PI from the left and right arteries (Mean UtAPI) was calculated and the prevalence of unilateral or bilateral "notch" documented. Normal reference values for each gestational week were constructed, and reproducibility analyzed.

RESULTS

There was a negative correlation between the gestational age and PI values from both arteries (Mean UtAPI = 1.57 + -0.02 X WG, r2= 0.07; PI UmA = 1.56 + -0.02 X WG, r2= 0.15). The prevalence of unilateral and bilateral "notch" in the uterine arteries was (median) 5% (range 3-10%), and 17% (range 4-23%), respectively. Reproducibility analysis for calculation of the Mean UtAPI showed an intraclass and interclass correlation coefficients of 0.87 (95% confidence intervals [CI] 0.74 - 0.93) and 0.78 (95% CI 0.59-0.88), respectively, and for UmAPI, 0.97 (95% CI 0.93-0.98) and 0.94 (95% Cl 0.88-0.97), respectively. Agreement analysis between observers for the calculation of the Mean UtAPI showed a mean difference of 0.01 (SD, 0.13) (95% limits of agreement [95% LA] -0.27-0.28) and for the UmAPI mean difference of 0.04 (SD 0.16) (95% LA, -0.29 - 0.36).

CONCLUSION

The reference values here obtained of the mean UtA PI and UmAPI can be applied in the clinical surveillance of normal and complicated pregnancies.