Arteries In Normal Pregnancies Research Articles

Doppler Waveform Indices of Foetal Middle Cerebral Artery in Normal Pregnancies: Correlation with Gestational Age of 20 to 40 Weeks

Doppler Waveform Indices of Foetal Middle Cerebral Artery in Normal Pregnancies: Correlation with Gestational Age of 20 to 40 Weeks

Longitudinal assessment of spiral and uterine arteries in normal pregnancy using novel ultrasound tool.

To use superb microvascular imaging (SMI) to evaluate longitudinally spiral artery (SA) and uterine artery (UtA) vascular adaptation in normal human pregnancy, and to develop reference ranges for use at various gestational ages throughout pregnancy. The data for this study were obtained from the National Institutes of Health (NIH)-funded Human Placenta Project. Women aged 18-35 years, with a body mass index < 30 kg/m2 , without comorbidities, with a singleton gestation conceived spontaneously, and gestational age at or less than 13 + 6 weeks were eligible for inclusion. The current analysis was restricted to uncomplicated pregnancies carried to term. Exclusion criteria included maternal or neonatal complications, fetal or umbilical cord anomalies, abnormal placental implantation or delivery < 37 weeks. Women who fulfilled the inclusion criteria formed the reference population of the Human Placenta Project study. Each participant underwent eight ultrasound examinations during pregnancy. The pulsatility index (PI) of both the left and right UtA were obtained twice for each artery and the presence or absence of a notch was noted. Using SMI technology, the total number of SA imaged was recorded in a sagittal placental section at the level of cord insertion. The PI and peak systolic velocity (PSV) were also measured in a total of six SA, including two in the central portion of the placenta, two peripherally towards the uterine fundal portion, and two peripherally towards the lower uterine segment. A total of 90 women fulfilled the study criteria. Maternal UtA-PI decreased throughout the first half of pregnancy from a mean ± SD of 1.39 ± 0.50 at 12-13 weeks' gestation to 0.88 ± 0.24 at 20-21 weeks' gestation. The mean number of SA visualized in a sagittal plane of the placenta increased from 8.83 ± 2.37 in the first trimester to 16.99 ± 3.31 in the late-third trimester. The mean SA-PI was 0.57 ± 0.12 in the first trimester and decreased progressively during the second trimester, reaching a nadir of 0.40 ± 0.10 at 24-25 weeks, and remaining constant until the end of pregnancy. SA-PSV was highest in early pregnancy with a mean of 57.16 ± 14.84 cm/s at 12-13 weeks' gestation, declined to a mean of 49.38 ± 17.88 cm/s at 20-21 weeks' gestation and continued to trend downward for the remainder of pregnancy, reaching a nadir of 34.50 ± 15.08 cm/s at 36-37 weeks' gestation. A statistically significant correlation was noted between SA-PI and UtA-PI (r = 0.5633; P < 0.001). Multilevel regression models with natural cubic splines were used to create reference ranges of SA-PSV and SA-PI for given gestational ages. From early gestation, we have demonstrated the ability to image and quantify SA blood flow in normal pregnancy, and have developed reference ranges for use at various gestational ages throughout pregnancy. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First trimester placental extracellular vesicles likely contribute to the vasodilation of maternal resistance arteries in normal pregnancy

During the first trimester of pregnancy, there is a large decrease in systemic vascular resistance (SVR) which coincides temporally with increasing extrusion of extracellular vesicles (EVs) from the placenta. We hypothesized that placental EVs may be one of the mechanisms contributing to maternal vasodilation.Macro-, micro-, nano-EVs from human first trimester placenta, or control injections containing EVs derived from fresh culture media, were injected into pregnant mice at day 12.5. After 30 min or 24 h, second order resistance arteries assessed for their reactivity to various vasomodulators.Placental EVs induced an anti-constrictive, pro-vasodilatory effect in maternal resistance arteries compared to control injections after 24 h suggesting that placental EVs may contribute to the maternal vasodilation during pregnancy.

Kynurenine Relaxes Arteries of Normotensive Women and Those With Preeclampsia.

[Figure: see text].

950: Longitudinal assessment of fetal placental arterioles and umbilical artery in normal pregnancies using novel tools

Technological limitations have hindered understanding of the physiology of fetal placental arterioles (FPA). Novel ultrasound (US) tools can now visualize and quantify microvascular flow. To our knowledge longitudinal study of FPA in pregnancy has not been done. Our objective was to determine the physiological changes in FPA across pregnancy and the response of the umbilical artery (UA) to these changes. Normal pregnant women with singletons were consented for serial US starting between 12 0/7 and 13 6/7 wks. US was performed every 2 wks until 16 wks, then every 4 wks until delivery. Visualization of FPA was achieved by novel microvascular color imaging on sagittal section of the placenta at the cord insertion level. Number of FPA visualized (FPA#), peak systolic velocity (FPA-PSV) and Pulsatility Index (FPA-PI) were obtained by averaging 6 measurements per US. Umbilical artery PI (UA-PI) was obtained at each US, starting at 15-16 wks. Women with BMI >30 kg/m2 at enrollment or who developed any complication were excluded. Pearson's correlation was used to test for associations. 83 women were included in this study with 8 US per pregnancy. Nomograms were developed for FPA# and FPA-PSV (Figure 1) and FPA-PI and UA-PI (Figure 2). Cubic polynomial models represented best fit for FPA-#, PSV and PI. Linear regression represented best fit for UA-PI. FPA-# and FPA-PSV (Figure 1) increased and FPA-PI and UA-PI (Figure 2) decreased throughout gestation. The steepest decline in slope of FPA-PI was in the 3rd trimester (Figure 2). Strong positive correlation was noted between UA-PI and FPA-PI (R 0.67, p< 0.0001). In vivo evaluation of FPA is feasible. Reduced impedance of fetal placental bed is noted in early gestation and continues throughout pregnancy with an accelerated drop in the 3rd trimester. Increased FPA-PSV is driven by reduced FPA impedance along with increased fetal cardiac output. UA Doppler change in pregnancy is primarily driven by adaptation of FPA.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

949: Noninvasive longitudinal assessment of spiral and uterine arteries in normal pregnancies using novel ultrasound tools

949: Noninvasive longitudinal assessment of spiral and uterine arteries in normal pregnancies using novel ultrasound tools

Blood flow parameters of posterior cerebral artery in normal pregnancy during middle and late stage

To study the blood flow parameters for 2 anatomical segments of posterior cerebral artery (PCA) in normal singleton fetal. Methods: The blood flow velocity parameters peak systolic velocity (PSV), end diastolic velocity (EDV), time-average maximum velocity (TAMAXV), velocity time integral (VTI) and resistance parameters systolic peak velocity and end diastolic velocity ratio (S/D), pulsatility index (PI), resistance index (RI) for 2 anatomical segments in PCA were recorded. The first segment of the PCA (PCAS1) was recorded between the origin of PCA and the proximal part of the posterior communicating artery. The second segment of the PCA (PCAS2) was recorded at the distal part of the posterior communicating artery. The blood parameters in both PCAS1 and PCAS2 were analyzed by using Pearson correlation and multiple curves fitting with gestational age (GA). Paired student's t test was performed to compare the difference in blood parameter between PCAS1 and PCAS2. Results: The blood flow velocity parameters in both PCAS1 and PCAS2 were increased with the GA (P<0.0001), with the best fitted curves of Quadratic curve (P<0.0001). There were no correlations between resistance parameters in PCA and GA (P>0.05). Resistance parameters in PCAS1 were higher than those in PCAS2 (P<0.05). Conclusion: The blood flow velocity parameters in both PCAS1 and PCAS2 are increased with GA. The resistance parameters in both PCAS1 and PCAS2 do not change with GA. Study on the velocities and resistance in these 3 arterial branches provides a more comprehensive evaluation on the process of brain circulation.

Innervation of the placenta and uterus: Competition between cytotrophoblasts and nerves?

In normal pregnancy, invasion of the uterus by trophoblasts is followed by dramatic elimination of the rich uterine innervation present in the non-pregnant state, and by remodeling of maternal spiral arteries. In general, the healthy survival of vascular smooth muscle requires innervation, but whether denervation plays a role in stripping of vascular smooth muscle from spiral arteries in normal pregnancy has not been explored. We propose that the temporal and spatial association of trophoblast invasion with denervation in pregnancy may involve competitive interaction between the invading trophoblast and persisting neurons. We suggest feasible experiments to explore the possible effects of such trophoblast-nerve competition on spiral artery remodeling.

Doppler Flow Velocity Indices (RI, PI, S/D &amp; PSV) of Fetal Middle Cerebral Artery in Normal Pregnancies: Correlation with Gestational Age of 20 to 40 Weeks

This observational type of descriptive study was carried out in the Department of Radiology and Imaging, BIRDEM selecting 70 Bangladeshi pregnant babies with the aim to find out the normogram of foetal middle cerebral artery Doppler flow velocity indices and correlation between Doppler flow velocity indices [Resistance Index (RI), Pulsatility Index (PI), Systolic/Diastolic ratio (S/D) &amp; Peak Systolic Velocity (PSV)] of foetal middle cerebral artery and gestational age in normal pregnancies of 20 to 40 weeks. It was observed that RI, PI and S/D were decreased with the advance of gestational age but PSV was increases with the advance of gestational age. Statistical analyses showed there were significant difference between mean PSV, RI and PI before and after 25 weeks of gestation. No significant difference was found between mean S/D before and after 25 weeks of gestation. It was observed from Correlation analysis between Doppler indices with independent gestational age that all the Doppler indices of foetal middle cerebra artery was positively correlated with the whole gestation period. The statistical analysis showed only PSV and RI were significantly correlated with the gestational age. Simple regression analysis between dependent Doppler index with independent gestational age before and after 25 weeks revealed that all the Doppler indices had positive relationship with the corresponding gestational age but relationship between PSV and PI (before 25 weeks) with their corresponding gestational ages were only statistically significant.DOI: http://dx.doi.org/10.3329/birdem.v2i2.12306 Birdem Med J 2012; 2(2) 77-80

Reference Values for Blood Flow Velocity in the Uterine Artery in Normal Pregnancies from 18 Weeks to 42 Weeks of Gestation Calculated by Automatic Doppler Waveform Analysis

The goal of the present study was to establish new Doppler reference ranges for maternal heart rate, intensity-weighted mean blood flow velocities (Vmean) and impedance indices (PI, RI) for the uterine artery by automated waveform analysis. A cross-sectional prospective study of 921 low-risk pregnancies was performed at 18-42 weeks of gestation. Uterine blood flow velocities were derived with pulsed-wave color Doppler. Measurements were carried out 1 to 2cm above the crossing of the uterine and external iliac arteries. Reference ranges for the individual measuring parameters were constructed based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle. A significant increase in intensity-weighted mean uterine blood flow velocities was observed at 18-42 weeks of gestation (Vmean=43cm/s to 50cm/s (p<0.001)). Reference curves for the pulsatility and resistance indices (PI, RI) significantly decreased with progressing gestation (PI: 18 weeks: 0.89; 42 weeks: 0.65 and RI: 18 weeks: 0.45; 42 weeks: 0.35). No significant PI and RI differences were observed when different placental locations were compared. The maternal heart rate decreased from 88 bpm to 77 bpm. Normal ranges for blood flow velocities and impedance indices in the uterine artery were established by Doppler ultrasound antenatal examinations of a large population of low-risk pregnancies. The data are proposed as reference curves to allow the early diagnosis of maternal and fetal risks.

Doppler Velocimetry of the Ophthalmic Artery in Normal Pregnancy

This study aimed at analyzing the correlation between ophthalmic Doppler indices and gestational age (GA) in healthy patients with singleton pregnancies. Intraobserver reproducibility and right-to-left eye correlation were also evaluated. Healthy pregnant women (n = 289) at 20 to 40 weeks' GA were evaluated. The resistive index (RI), pulsatility index (PI), and peak ratio (PR) were determined by 2 measurements in each eye. Comparisons were performed first between the 2 measurements in each eye and later between the right and left eyes. Spearman rank correlation was used to analyze the relationship of the RI, PI, and PR with GA. Linear regression analysis was also performed. No significant differences were found between the values obtained for the first and the second measurements in each eye and those for the RI, PI, and PR in the right and left eyes. There was a significant decrease in RI and PI values with advancing GA, however (rho = -0.264 and -0.1192, respectively), with low R(2) values for both. Thus, only a small proportion of the variations observed in the RI and PI was associated with changes in GA. No significant difference was found between the PR values with regard to GA intervals. Doppler velocimetry is a reproducible technique for evaluation of the RI, PI, and PR in the ophthalmic artery. Unilateral analysis of these indices can be used. Linear regression analysis indicated that other factors were associated with a decrease in the RI and PI values with advancing GA. No significant change was observed in the PR values throughout normal pregnancy.

PLAC1 mRNA in Maternal Blood Correlates with Doppler Waveform in Uterine Arteries in Normal Pregnancies at the Second and Third Trimester

Doppler analysis of the uterine arteries is currently used for pre-eclampsia (PE) screening. PLAC1 is a trophoblast-specific gene, and it is known that in normal pregnancies, trophoblastic cells are released into the maternal circulation, where specific trophoblastic mRNA can be detected. In PE, as in women who eventually develop PE, an abnormal passage of fetal and placental cells is also present. In this study, we aimed to verify whether, in normal pregnancies, Doppler waveform of the uterine arteries correlates with PLAC1 mRNA concentrations. Thirteen cases of normal pregnancies at 37 weeks' gestation (23-41) were enrolled in the study. PLAC1 mRNA was extracted from 2 mL of blood by ABI PRISM 6100 nucleic acid Prep Station (Applied Biosystems, Foster City, CA) and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed by a PE 5700 Sequence detection system. Bulk RNA from normal placental tissue was used as the reference curve, and the amount of PLAC1 mRNA in the study samples was then expressed as the "relative amount" of weight of placental tissue (ng/mL). The uterine arterial mean resistance index (RI) and presence/absence of a dicrote waveform were calculated by using a 5 MHz transabdominal probe (Tecnos, ESAOTE) at the uterine cervico-corporal junction. Doppler measurement was performed on the same day as blood collection. The median of the means of uterine arterial RI was 0.52 (0.39-0.68). RI of uterine arteries and PLAC1 mRNA were significantly correlated in a log-linear regression (R(2) = 0.483, P = 0.024). Our data support that in normal pregnancy, the passage of trophoblast material into the maternal circulation is correlated with the quantitative measurement of uterine hemodynamics.

Circulating Angiogenic Factors and Abnormal Uterine Artery Doppler Velocimetry in the Second Trimester

Objective: Circulating angiogenic growth factors (such as vascular endothelial growth factor [VEGF] and placental growth factor [PlGF]) and their interaction may be associated with vascular remodeling of spiral arteries in normal pregnancy. Soluble Flt-1, an antagonist of both VEGF and PlGF, has been shown to be increased, while PlGF is decreased in women prior to the onset of preeclampsia. The purpose of this study was to compare maternal soluble Flt-1 and PlGF levels in the second trimester with a marker of abnormal placentation, abnormal uterine artery Doppler (UAD). Method: A prospective cohort of women, 16 to 24 weeks estimated gestational age (EGA), with singleton pregnancies, underwent UAD and phlebotomy. Maternal soluble Flt-1 and free PlGF were measured by ELISA in samples from women with abnormal UAD with a group, controlled for EGA, with normal UAD. Mann-Whitney Rank-Sum test was used to compare maternal serum levels of both soluble Flt-1 and PlGF between women with abnormal uterine artery Doppler versus women with normal uterine artery Doppler. Results: Of the 222 study subjects enrolled, 34 (15%) had abnormal UAD. The mean EGA at enrollment of subjects in each group was 18 weeks. There was no difference in PlGF between subjects with abnormal UAD (median, 191 pg/mL; range, 187 to 337 pg/mL) versus controls (median, 171 pg/mL; range, 169 to 289 pg/mL) (p = 0.59) or soluble Flt-1 (median, 780 pg/mL; range, 280 to 3200 pg/mL) or between subjects with abnormal UAD versus controls (median, 720 pg/mL; range, 220 to 1980 pg/mL) (p = 0.36). Conclusion: Concentrations of maternal soluble Flt-1 and free PlGF in the second trimester do not appear to be altered in women with abnormal UAD. This suggests that these biochemical markers are independent of the increased placental resistance seen with abnormal uterine artery Doppler.

Doppler sonography of the uterine and the cubital arteries in normal pregnancies, preeclampsia and intrauterine growth restriction: evidence for a systemic vessel involvement

The decrease in uterine resistance during normal pregnancy is known to be related to invading trophoblast cells which derive from placental tissue. Uterine and peripheral resistance is elevated in preeclampsia. The aim of the present study was to prospectively examine uterine and peripheral resistance in pregnancies complicated by preeclampsia (PE), fetal intrauterine growth restriction (IUGR) and pregnancy induced hypertension (PIH). Sixty-seven women with normal pregnancies, 17 with PE, 12 with IUGR underwent Doppler sonographic investigation of the uterine and the cubital arteries. The Pulsatility Index (PI) was calculated for each vessel. Statistical analysis was performed and a P-value <0.05 was considered significant. Patients with preeclampsia and IUGR showed a significant higher resistance at the placental (mean PI 1.267 and 1.063), nonplacental (mean PI 1.631 and 1.124) and cubital artery (mean PI 3,777 and 3.995) compared to the normal pregnancy group (mean PI 0.678; 0.859 and 2.95 respectively). Mean birth weight in the PE group was 1409 g, in the IUGR group 1649 g and 3419 g in the normal pregnancy group. Pregnancies with IUGR are associated with elevated peripheral resistance in the maternal arterial system as seen in pregnancies with preeclampsia. Our findings encourage to further investigate the maternal vascular system in high risk pregnancies.

The mechanism of EDHF-mediated responses in subcutaneous small arteries from healthy pregnant women.

We studied the importance of endothelium-derived hyperpolarizing factor (EDHF) vs. nitric oxide (NO) and prostacyclin (PGI(2)) in bradykinin (BK)-induced relaxation in isolated small subcutaneous arteries from normal pregnant women. We also explored the contribution of cytochrome P-450 (CYP450) product of arachidonic acid (AA) metabolism, hydrogen peroxide (H(2)O(2)), and gap junctions that have been suggested to be involved in EDHF-mediated responses. Isolated arteries obtained from subcutaneous fat biopsies of normal pregnant women (n = 30) undergoing planned cesarean section were mounted in a wire-myography system. In norepinephrine-constricted vessels, incubation with N(G)-nitro-L-arginine methyl ester (L-NAME) resulted in a significant reduction in relaxation to BK. Simultaneous incubation with L-NAME and indomethacin failed to modify this response further. BK-mediated dilatation in the presence of K(+)-modified solution was decreased to similar level as obtained after incubation with L-NAME. Incubation with L-NAME abolished BK-induced responses in K(+)-modified solution. Sulfaphenazole, a specific inhibitor of CYP450 epoxygenase, and catalase (an enzyme that decomposes H(2)O(2)) did not affect the EDHF-mediated relaxation because concentration-response curves to BK were similar in arteries after incubation with L-NAME vs. L-NAME + sulfaphenazole and L-NAME + catalase. The inhibitor of gap junctions, 18 alpha-glycyrrhetinic acid, significantly reduced BK-mediated relaxation both without and with incubation with L-NAME. We found that both NO and EDHF, but not PGI(2), are involved in the endothelium-dependent dilatation to BK. BK-induced relaxation is almost equally mediated by NO and EDHF. CYP450 epoxygenase metabolites of AA or H(2)O(2) do not account for EDHF-mediated response; however, gap junctions are involved in the EDHF-mediated responses to BK in subcutaneous small arteries in normal pregnancy.

P096: Ultrasonic fetal and placental tissue characterisation and the role of Doppler ultrasound in lung maturity

The aim of this study is to known the relationship between the gestational age and quantitative assessment of ultrasonic signs of placental tissue, fetal lungs and liver tissue and to correlate Doppler parameters from main stems of the pulmonary arteries for determining fetal lung maturity in normal pregnancy and pregnancy with preeclampsia and diabetes. The placenta, fetal lungs and fetal liver in 300 normal pregnancies, 150 preeclamptic pregnancies and 150 diabetic pregnancy were examined by ultrasound at 30–41 weeks of gestation. The coefficients of variation (the standard deviation divided by the mean value) were used to characterise the tissue in different groups during pregnancy. Doppler velocimetry was performed in the main stems of pulmonary arteries in normal pregnancies and pregnancies with preeclampsia and diabetes. The coefficients of variation in mature foetuses were greater than 29% for placentas in-vivo, greater than 34% for placentas in-vitro, greater than 28% for liver tissue and greater than 30% for lung tissue. Placental, lung and liver tissue of diabetic pregnancy tended to have lower coefficients of variation throughout their pregnancies. We found in mature foetuses mean peak systolic velocity higher than 40 cm/sec. and PI lower than 3.00. In mature foetuses with preeclampsia we found higher mean peak systolic velocity in comparing with normotensive patients, but in mature foetuses with diabetes we found lower peak systolic velocity in comparing with normotensive patients. The coefficient of variation values for placentas in-vivo and in-vitro, and fetal lungs and liver increase during pregnancy in normal and preeclamptic patients with increasing gestational age and decrease in diabetic patients. The mean peak systolic velocity in pulmonary arteries increase during pregnancy in normal and preeclamptic patients and decrease in diabetic patients.

The role of gap junctions in mediating endothelium‐dependent responses to bradykinin in myometrial small arteries isolated from pregnant women

Endothelium-dependent responses were assessed in myometrial small arteries isolated from pregnant women, using pressure myography. Responses to bradykinin were unaffected by the combined presence of the nitric oxide synthase (NOS) inhibitor, N-nitro-L-arginine methyl ester (L-NAME, 100 micro M) and the cyclo-oxygenase inhibitor, indomethacin (10 micro M). The additional presence of clotrimazole (50 micro M) attenuated, but did not abolish, vasodilator responses to bradykinin. Raising extracellular [K(+)] (by between 1 and 15 mM) did not evoke a vasodilator response, nor did the cannabinoids, anandamide and methanandamide. Responses to bradykinin were attenuated in the presence of the gap junction inhibitors 18-alpha-glycyrrhetinic acid (18-alpha GA, 100 micro M), carbenoxolone (100 micro M) and palmitoleic acid (50 micro M). SR141716A, the CB(1) receptor antagonist attenuated responses to bradykinin, but only at high concentrations (10 micro M). These results suggest that gap junctional communication is involved in the nitric oxide (NO)- and prostanoid-independent vasodilator responses to bradykinin in myometrial small arteries in normal pregnancy.

Differential mechanisms of endothelium-dependent vasodilator responses in human myometrial small arteries in normal pregnancy and pre-eclampsia

Differential mechanisms of endothelium-dependent vasodilator responses in human myometrial small arteries in normal pregnancy and pre-eclampsia

Differential mechanisms of endothelium-dependent vasodilator responses in human myometrial small arteries in normal pregnancy and pre-eclampsia.

Pre-eclampsia is a pregnancy-specific disorder associated with hypertension and proteinuria, characterized by alterations in endothelial cell function. In the present study we have compared responses to the endothelium-dependent vasodilator, bradykinin, in small myometrial arteries from normal pregnant and non-pregnant women and women with pre-eclampsia, in order to assess the relative contributions of nitric oxide, endothelium-derived hyperpolarizing factor (EDHF) and prostanoids in mediating endothelium-dependent vasodilatation. Bradykinin-induced concentration-dependent relaxation in arteries isolated from the three subject groups did not differ with regard to sensitivity or maximum response. Responses to bradykinin in all three groups were unaffected by cyclo-oxygenase inhibition alone, and were similarly unaffected by partial depolarization. The nitric oxide synthase (NOS) inhibitor, N-nitro-l-arginine methyl ester, significantly attenuated the responses to bradykinin in arteries from non-pregnant women and almost abolished responses in arteries from women with pre-eclampsia. However, in arteries from normal pregnant women, bradykinin-induced responses were maintained in the presence of NOS inhibition. Inhibition of NOS combined with partial depolarization abolished responses to bradykinin in these vessels. These results support the suggestion that, in the absence of NO, an EDHF can mediate vasodilator responses to bradykinin during normal pregnancy, an effect not apparent in arteries from non-pregnant women or women with pre-eclampsia. The up-regulation of EDHF-type function may represent a vascular adaptation to normal pregnancy that is absent in pre-eclampsia, and this might contribute to the clinical features of the disease.

Investigation of intraplacental villous arteries by doppler flow imaging in growth-restricted fetuses

Objective: The purposes of our study were to assess the ability of color and power Doppler sonography to depict the blood flow in the intraplacental villous arteries and to evaluate whether the blood flow of intraplacental villous arteries in a normal pregnancy is different from that in a pregnancy that is associated with intrauterine growth restriction. Study Design: Eighty-five women with uncomplicated pregnancy and 16 women with intrauterine growth-restricted fetuses between 27 and 38 weeks of gestation were examined by color and power Doppler imaging. The blood flow of intraplacental villous arteries was analyzed comparatively. The pulsatility index and peak systolic velocity were measured. Results: A unit of 1 intraplacental villous artery-1 and its branches were seen as 1 cotyledon by color and power Doppler imaging. The cotyledon was easily identified and counted. Each cotyledon contained only 1 intraplacental villous artery-1. This method can visualize the intraplacental villous artery-1 to intraplacental villous artery-4 in normal pregnancies. The terminal villous arteries beyond intraplacental villous artery-4 were not imaged. The number of detectable intraplacental villous artery-1 in 1 placenta in intrauterine growth restriction was significantly lower than that in normal pregnancy. The number of detectable branches in intrauterine growth restriction was also significantly lower than in normal pregnancy. No intraplacental villous artery-4 blood flow was found in women with intrauterine growth restriction. In examined arteries, pulsatility index decreased and peak systolic velocity increased significantly with advancing gestational age (P <.02). At any given gestational age, pulsatility index and peak systolic velocity in the peripheral arteries were significantly lower than those in the upstream arteries in normal pregnancy (P <.001). The pulsatility index value of each intraplacental villous artery was also lower than that of the umbilical artery in the women with intrauterine growth restriction (P <.05). There were no differences in pulsatility index in each artery between the groups, although there were a few high pulsatility index values in intrauterine growth restriction. Conclusion: Color Doppler and power flow sonography are valuable tools for the detection of the blood flow of intraplacental villous arteries. The decrease in the number of detectable intraplacental villous artery-1 and branches was associated with intrauterine growth retardation. (Am J Obstet Gynecol 2002;186:297-302.)