Parallel Doppler assessment of yolk sac and intervillous circulation in normal pregnancy and missed abortion.

This study assessed yolk sac morphology and vascularity and intervillous blood flow in normal early pregnancy and missed abortion. Transvaginal colour and pulsed Doppler were used in a prospective analysis of 87 normal pregnancies and 48 missed abortions between 6 and 12 weeks gestation. The Kruskal-Wallis rank test was used to calculate the difference in yolk sac diameter and vascularity visualization rate between gestational weeks. Repeated measures analysis of variance was used for comparison of the intervillous circulation between groups. The growth of the yolk sac was considered statistically significant between gestational weeks 6 and 9, being most prominent between 9 and 10 weeks of gestation. Vascularity of the yolk sac, characterized by low velocity and absence of diastolic flow, was demonstrated in 67 per cent of normal pregnancies. Yolk sac blood flow was detected in 19 per cent of the patients with missed abortion. Doppler analysis of the intervillous circulation demonstrated decreased peak velocity of the continuous flow in patients with missed abortion for gestational weeks 11 and 12. It is concluded that progressive decrease of yolk sac vascularity coincides with visualization of more prominent colour-coded areas within the intervillous space. In patients with missed abortion, such changes do not occur.

Contrast-enhanced, three-dimensional power Doppler sonography for differentiation of adnexal masses.

OBJECTIVE: To investigate the potential usefulness of contrast-enhanced, three-dimensional power Doppler sonography in the differentiation of benign and malignant adnexal lesions. METHODS: A total of 45 patients with complex adnexal lesions of uncertain malignancy at transvaginal B mode and/or color Doppler sonography were prospectively evaluated with three-dimensional power Doppler sonography before and after injection of contrast agent. Presence of a penetrating pattern and a mixed penetrating and peripheral pattern suggested adnexal malignancy. All the results were compared with histopathology. RESULTS: There were 12 cases of ovarian malignancy and 33 benign adnexal lesions. Of the 12 ovarian cancers, seven (58. 3%) showed vascular distribution suggestive of malignancy at nonenhanced three-dimensional power Doppler sonography. After injection of contrast agent, a penetrating vascular pattern and/or a mixed penetrating and peripheral pattern were detected in all cases of ovarian malignancy. One cystadenofibroma demonstrated penetrating vessels at initial scan, whereas two benign lesions (fibroma and cystadenofibroma) were misdiagnosed as malignant at contrast-enhanced, three-dimensional power Doppler sonography. The use of a contrast agent with three-dimensional power Doppler sonography showed diagnostic efficiency (95.6%) that was superior to that of nonenhanced three-dimensional power Doppler sonography (86. 7%). CONCLUSION: Contrast-enhanced, three-dimensional power Doppler sonography provides better visualization of tumor vascularity in complex adnexal masses. If used together with three-dimensional morphologic ultrasound assessment, enhanced three-dimensional power Doppler imaging might precisely discriminate benign from malignant adnexal lesions.

Doppler assessment of the intervillous blood flow in normal and abnormal early pregnancy.

OBJECTIVE: To compare resistance index (RI) and pulsatility index (PI) in the spiral and intervillous arteries, and peak systolic velocity of the continuous intervillous flow in normal and abnormal first-trimester pregnancy. METHODS: Transvaginal color and pulsed Doppler were used in a prospective analysis of 60 normal (controls) and 54 abnormal (30 missed abortions and 24 anembryonic) pregnancies (6-12 weeks' gestation). Repeated-measures analysis of variance was used for comparison between groups. RESULTS: A gradual decrease in spiral artery RI and PI was found in women with anembryonic pregnancies. No difference in spiral artery impedance was noted in women with normal pregnancies, but there was a progressive increase in spiral artery RI and PI in women with missed abortion. A significant increase in continuous intervillous blood flow velocity was noted from the 11th week onward in the normal pregnancy group (8.0 +/- 0.9 versus 12.2 +/- 1.4 cm/second). Intervillous arterial blood flow signals did not demonstrate any difference in RI and PI with advancing gestational duration. Significantly lower PI values were obtained from the intervillous arteries in women with anembryonic pregnancy (PI 0.54 +/- 0.04) than in controls (PI 0.80 +/- 0.04) and those with missed abortions (PI 0.75 +/- 0.04). However, there was no statistically significant difference in the intervillous RI between subgroups. CONCLUSION: The new generation of sensitive Doppler units can detect intervillous flow as a continuous progressive process during the first trimester of normal and abnormal pregnancy. There is a significant difference in intervillous artery vascular impedance between normal and anembryonic pregnancies.

Scoring system for prediction of ovarian endometriosis based on transvaginal color and pulsed Doppler sonography.

OBJECTIVE: To develop a new noninvasive scoring system using clinical signs and symptoms, CA-125 levels, sonographic findings, and transvaginal color and pulsed Doppler parameters for preoperative recognition of ovarian endometriosis. DESIGN: A 5-year prospective study in patients undergoing laparotomy and laparoscopy. SETTING: Department of Obstetrics and Gynecology, University of Zagreb, Sveti Duh Hospital, Zagreb, Croatia. PATIENTS: Six hundred fifty-six benign and malignant adnexal masses, among which 103 were surgically proved to be ovarian endometriosis. INTERVENTIONS: All patients undergoing laparotomy and laparoscopy were examined by transvaginal ultrasonography with color Doppler imaging. Serum levels of CA-125 were measured the day before surgery. MAIN OUTCOME MEASURE: The total score was applied in all patients with adnexal masses. RESULTS: The scoring system proved to be very useful in distinguishing ovarian endometriosis from other benign and malignant ovarian lesions, with a sensitivity of 99.02% and a specificity of 99.64%, compared with morphological scoring system's sensitivity of 83.91% and specificity of 97.12%. CONCLUSION: The new noninvasive scoring system improves significantly the ability to discriminate between endometriosis and other benign and malignant ovarian entities.

Uterine and ovarian perfusion during the periovulatory period assessed by transvaginal color Doppler.

OBJECTIVE: To measure the flow velocity of the uterine, radial, spiral, and ovarian arteries during the periovulatory period in spontaneous and induced ovarian cycles with confirmed ovulation. DESIGN: Daily measurements during the periovulatory period in 78 patients attending an infertility clinic because of the male factor in infertility. RESULTS: Uterine flow velocity in spontaneous cycles has a pulsatility index (PI) of 3.16 2 days before ovulation and starts to decrease the day before ovulation (PI = 2.22). In stimulated cycles these changes do not occur, and mean PI of 3.06 remains at that level during the periovulatory period. Clear flow velocity waveforms are obtained from the endometrium and myometrium around the time of ovulation. Data obtained from the radial arteries suggest better myometrial perfusion in patients with natural cycles. Spiral artery flow velocity in spontaneous cycles has a PI of 1.13 the day before ovulation and a nadir of 0.72 is reached the day after ovulation. On the contrary, the mean PI of the spiral artery blood flow in the group with ovulation induction rises during the day before ovulation (PI = 2.32) and reaches a nadir of 1.09 the day after ovulation. CONCLUSIONS: These data suggest the presence of better uterine receptivity during the periovulatory phase of natural cycles compared with induced ovarian cycles. Endometrial perfusion presents accurate noninvasive assay of uterine receptivity that may be used to predict implantation success rate, to reveal unexplained infertility problems, and to select patients for correction of endometrial perfusion abnormalities by an appropriate treatment.

Ovarian senescence and its significance on uterine and ovarian perfusion.

OBJECTIVE: To measure the flow velocity of the ovarian, uterine, radial, and spiral arteries in different age groups. DESIGN: Serial measurements throughout the menstrual cycle in normal cycling women with documented fertility were compared with those in postmenopausal patients with and without hormone replacement therapy (HRT). SETTING: Department of Obstetrics and Gynecology, University of Zagreb, Sveti Duh Hospital, Zagreb, Croatia. PATIENTS: Two hundred fifty patients were analyzed: 120 healthy fertile women, 85 postmenopausal patients, and 45 postmenopausal patients receiving HRT. INTERVENTIONS: All patients were examined by transvaginal color and pulsed Doppler. MAIN OUTCOME MEASURE: Changes in the resistance index of flow velocity waveforms of the ovarian, uterine, radial, and spiral arteries. RESULTS: Ovarian artery Doppler measurements in postmenopausal patients showed a significant difference when compared with the ovarian artery on the side containing dominant follicle or corpus luteum in healthy fertile group. Uterine and radial artery flow velocity analyses demonstrated significant positive correlations between the resistance index and years of menopause. In patients receiving HRT, a lowering effect occurred in the resistance index of the main uterine artery and its intramyometrial branches. Visualization of clear Doppler signals from the spiral arteries was possible in 30% of women who were menopausal for < 5 years. Increased vascular impedance was the typical finding in this vessel for this group of patients. The addition of HRT resulted in higher visualization rates of the spiral arteries and lowered resistance index values. CONCLUSIONS: There are changes in the flow velocity patterns of the ovarian, uterine, radial, and spiral arteries with age. The fact that the uterine artery resistance index does not change significantly in the first postmenopausal years strongly supports the thesis that the aging process initially affects the uterus less than the ovary. Furthermore, the uterine environment can be manipulated more easily during the menopausal years by proper hormonal stimulation.

Three-dimensional sonography for assessment of morphology and vascularization of the fetus and placenta.

OBJECTIVE: To analyze the potential of three-dimensional power Doppler sonography in morphologic and functional assessment of the fetus and placenta. METHODS: Review of the recent literature on three-dimensional sonography in early pregnancy and in the second and third trimester. RESULTS: Three-dimensional sonography plays an important role in obstetrics predominantly for assessing fetal anatomy. Multiplanar images and rotation of the object allow systematic review of anatomic structures, such as limb buds, cerebral cavities, cord insertion, stomach, and bladder. Using this modality, volumes of the gestational sac, yolk sac, and fetal organs can be obtained easily. Three-dimensional power Doppler sonography has the potential to study the intervillous and placental circulation and evaluate the development of the embryonic and fetal cardiovascular system. CONCLUSIONS: Three-dimensional ultrasound imaging complements pathologic and histologic evaluation of the developing embryo, giving rise to the new term "three-dimensional sonoembryology." It is evident that three-dimensional ultrasonography improves the visualization of the normal and abnormal fetal anatomy giving a realistic impression of the extent of the defects. These data are useful not only for obstetricians but also for pediatricians and pediatric surgeons.

The value of transvaginal color Doppler in the assessment of pelvic inflammatory disease.

This study compares transvaginal color and pulsed Doppler (TVCD), laparoscopic and clinical findings in 102 women with proven pelvic inflammatory disease (PID). Seventy-two (72) of them had acute symptoms, 11 presented with chronic pelvic pain and 19 patients were infertility cases suspected of tubal etiology. Uterine sonographic findings were demonstrated in 72 patients (70.6%). Free fluid in the cul-de-sac was demonstrated in 39 (38.2%) patients. Ovarian enlargement as the only finding was demonstrated in 6 (5.9%) patients, 22 (21.6%) presented with tubular adnexal structure, while in 74 (72.5%) patients it was of a complex nature. Color flow was obtained in all 6 patients presenting with ovarian enlargement, in 12 (54.5%) of those presenting with tubular adnexal structure, and in 56 (75.7%) of those with complex adnexal mass. Ovarian morphology was clearly delineated from adnexal mass in 59 patients (55.9%). The ipsilateral ovarian flow was altered in 50 of them (84.7%). The mean resistance index (RI) in patients with acute symptoms was 0.53 +/- 0.09 (+/-SD). It significantly differed from those obtained in patients with chronic pelvic pain (RI = 0.71 +/- 0.07) and infertility cases (RI = 0.73 +/- 0.09). We concluded that transvaginal color Doppler is useful additional tool in diagnosis and treatment monitoring in patients with PID.

The assessment of uterine and ovarian perfusion in infertile patients.

OBJECTIVE: To evaluate ovarian and uterine perfusion in 790 infertile patients. STUDY DESIGN: Transvaginal color Doppler assessment of the ovarian and uterine circulation in infertile patients with benign pelvic lesions, uterine anomalies and ovarian or uterine dysfunction. RESULTS: Uterine anomalies were detected in 146 patients: 135 septate and 11 bicornute uteri. No alteration, in terms of resistance index (RI), was detected for main uterine arteries in patients with duplication anomalies of the uterus. Submucous fibroids were identified in 25 patients, while subserous leiomyoma were diagnosed in five patients. The mean RI for these lesions covered the value of 0.55 +/- 0.09. Endometrial polyps altered the endometrial perfusion in 26 infertile patients (RI = 0.48 +/- 0.06), while 11 avascular intrauterine synechiae were identified. Functional ovarian cysts were transitory present in 59 patients. The RI varied from 0.52 +/- 0.06 for follicular and 0.46 +/- 0.08 for corpus luteum cysts. Ovarian endometrioma were visualized in 78 infertile patients. Forty eight of them were vascularized at the level of the hilus, while 16 showed pericistic vascular location (RI ranged from 0.40 to 0.59). Dermoid cysts (n = 12) were mostly avascularized (75%), while polycystic ovaries demonstrated increased intraovarian vascularity in all the examined cases. The mean RI detected within the ovarian stroma was 0.52 +/- 0.06. In 11 patients premature menopause was predicted due to low volume of the ovary (< 2 cm3) and absence of the intraovarian vascularity. Hydrosalpynx or sactosalpynx were imaged in 154 patients. The RI varied from 0.44 in acute to 0.74 in chronic stage of the disease. CONCLUSION: Transvaginal color Doppler allows precise estimation of the functional state of the reproductive organs in infertile patients.

The assessment of normal and abnormal luteal function by transvaginal color Doppler sonography.

OBJECTIVE: To evaluate intraovarian resistance index (RI) in 47 healthy fertile volunteers with ovulatory cycles, 28 patients with luteal phase defect (LPD) and four patients with luteinized unruptured follicle (LUF Sy). STUDY DESIGN: Transvaginal color Doppler assessment of the follicular and corpus luteum blood flow and plasma progesterone (P) levels were obtained in each patient. RESULTS: Significantly higher intraovarian artery RI (< 0.001) was obtained for LPD group than for controls during the luteal phase. In the control group both follicular and corpus luteum RI were significantly lower (P < 0.001) on the dominant side, while in LPD group no difference (P > 0.05) between the sides occurred. Mean P levels were significantly lower (P < 0.001) in the LPD group (6.9 +/- 2.3 ng/ml) than in controls (24.1 +/- 11.4 ng/ml). In all the LPD patients histopathology revealed delayed endometrial pattern, while normal endometrial dating was found in all the evaluated patients form the control group (n = 15). In the patients with LUF Sy (n = 4) similar RI values were obtained in the follicular and corpus luteum phase. There was no difference between the sides in terms of the intraovarian RI, while subnormal values of P were obtained in all the examined patients (14.1 +/- 6.2 ng/ml). CONCLUSIONS: Transvaginal color Doppler may predict the function capacity of the corpus luteum.

A combined Doppler and morphopathological study of ovarian tumors.

OBJECTIVE: To evaluate intratumoral blood flow in 46 patients with ovarian masses. METHODS: Transvaginal color Doppler was carried out in each patient prior to the laparoscopy or laparotomy. Tumors were analyzed according to the size, morphology, presence of the neovascularization, configuration and distribution of the tumoral blood vessels and pattern of the intratumoral blood flow. Vascular patterns of surgically removed tumors were studied microscopically. Three types of vasculature were analyzed: neovascular capillaries without media, sinusoidal thin walled spaces and normal vessels' morphology. The RI (resistance index) values were analyzed in relation to gross appearance, histological type of the tumor, existence of inflammation/necrosis area and vascularization pattern of the tumor. RESULTS: Neovascularization was found in all the malignant tumors with low RI (less than 0.42) and solid or solid cystic gross morphology. Neovascular signals were obtained in only one patient with ovarian endometrioma. Sinusoidal spaces were identified in all the malignant ovarian tumors, but also in most of the benign lesions. Normal vessel morphology was identified in 60% of malignant ovarian tumors and in all the patients with benign ovarian lesions. CONCLUSION: There is a significant correlation between Doppler and histopathological studies in terms of vascularization pattern analysis (detection of neovascular capillaries, sinusoidal spaces and normal vessels morphology). In most of the malignant ovarian tumors there were few areas of vascularization which can be analyzed non-invasively by transvaginal color and pulsed Doppler ultrasound.

First trimester malformation screening.

First trimester fetal malformation screening still represents a diagnostic challenge in modem obstetrics. Being solely dependent on ultrasound instrumentation, and the skill and experience of the operator, recently improved by introducing high frequency transvaginal approach and digital image processing. This opens a new field of ultrasound in obstetrics called sonoembriology. Until now sonoembriology in routine clinical practice resulted in numerous reports about early detection of rare anomalies and uncommon syndromes. The reported sensitivity of sonoembriology with a respect to a final pregnancy outcome was more than 60% of all malformations in total, while in combination with ultrasound screening in second trimester, increases to in excess of 80%. The commonest anomalies detected by sonoembriology are anomalies of the head and brain, heart, abdominal wall, unbilical cord, urinary tract and skeleton. There is an important role of sonoembriology in the assessment of the nuchal translucency in the screening programme for chromosomal anomalies. This changes the well-known concept "fetus as a patient" to "embryo as a patient" and opens new frontiers in fetal diagnosis and therapy.

[Three-dimensional ultrasonographic uterine vascularization and embryo implantation]. / Vascularisation de l'utérus en 3D et implantation.

During the last decade transvaginal color Doppler has played an important role in increasing the understanding of early human development. Although our knowledge of early pregnancy development has recently improved, little is known about the most critical period of human development: implantation. Recent advances in three-dimensional ultrasound have made studies of follicular development, ovulation and uterine receptivity more accurate. Three-dimensional ultrasound facilitates determination of the antral follicle number, ovarian volume calculation and analysis of the intensity of ovarian stromal blood flow in a short time without increasing the patient's discomfort. It is also possible to determine predictors of IVF outcome by three-dimensional ultrasound. Favorable ovarian stromal vascularity is associated with higher number of retrieved oocytes and increased pregnancy rates. The high degree of endometrial perfusion shown by color Doppler ultrasonography and on three-dimensional power Doppler histograms on the day of embryo transfer can indicate a more favorable endometrial milieu for successful in vitro fertilization. Uterine septum is the most common uterine abnormality occurring in infertile women. Three-dimensional ultrasound can be used as a screening method for detection of uterine abnormalities in patients suffering from infertility.

[Polycystic ovary syndrome--Doppler parameters]. / Policisticni ovarijski sindrom--doplerski parametri.

OBJECTIVE: To evaluate the value of transvaginal color and pulsed Doppler measurements of the uterine and ovarian arteries in infertile patients with polycystic ovarian syndrome (PCOS). STUDY DESIGN: Prospective controlled trial included forty (40) patients with PCOS and 40 healthy women. All the patients were examined by transvaginal color and pulsed Doppler on the 5th, 10th, 12th, 15th, 21st and 24th day of the menstrual cycle. The hormonal profile (estradiol (E2), luteinizing hormone (LH), follicular stimulating hormone (FSH), progesterone, testosterone and prolactin) was correlated to the Doppler results. RESULTS: The flow velocity patterns of uterine and ovarian vessels showed changes during the normal ovulatory menstrual cycle, while in the patients with PCOS these changes did not occur. The high resistance index (RI = 1.0) with reverse flow was detected in both ovarian arteries in PCOS group, and showed no cyclic changes. Ovarian stromal and hilar arterial impedance (0.54 +/- 0.05) as well as uterine artery resistance index (0.91 +/- 0.09) did not show significant changes during the menstrual cycle. CONCLUSIONS: Our study suggests that a large fraction of patients suffering from PCOS has elevated uterine artery resistance index despite normal plasma E2 levels. It can be postulated that excessive production of ovarian factor (other than E2) may increase the uterine resistance and alter the endometrial receptivity. This finding may explain why endometrial receptivity is shown to be poor in patients with PCOS. Estimation of uterine and ovarian arterial impedance values seems to have clinical impact in the management of these patients attending an in vitro fertilization program.

[Study of intervillous blood circulation using color and pulsed doppler ultrasound]. / Istrazivanje interviloznog optoka krvi s pomocu obojenog i pulzirajuceg Doplerskog ultrazvuka.

Studies of the formation and hemodynamics of intervillous circulation aroused great scientific interest in the past few years. The reason for this is development of the technology of color Doppler ultrasound, which can non-invasively in vivo follow-up changes in intervillous circulation during all three trimesters of gestation. The results of Doppler ultrasound measurements have been compared to histological and embryological findings. Different experimental findings and theories induced intensive scientific discussions about the timing of the formation of intervillous circulation, as well as about possible significance of hemodynamic changes in physiological and pathological processes in early and late gestation. In this review article we tried to acquaint the broader professional readership with this interesting subject, and to present our results and viewpoints after several years of the study of intervillous circulation with color Doppler.

[Angiogenesis of gynecologic tumors studied with color Doppler]. / Angiogeneza ginekoloskih tumora ispitana obojenim doplerom.

Angiogenesis is obligatory event in solid tumors growth. Weak muscular layer in the newly formed tumoral vessels results in decreased resistance to blood flow and characteristic Doppler signal. The number and arrangement of the blood vessels differ between benign and malignant lesions as well. Parameters mentioned above enable a precise ultrasound differential diagnosis between benign and malignant tumors. Malignant uterine tumors are better perfused and have lower resistance to blood flow than benign ones. Benign lesions with secondary changes (necrosis) may have lowered resistance indices. The finding of pathological perfusion makes the diagnosis of endometrial carcinoma also very accurate. High sensitivity of the transvaginal color Doppler in detecting newly formed blood vessels in an early stages of ovarian cancer may establish this technique as a screening method for this still very high lethality disease.

[Tumoral angiogenesis--hot topic in science again]. / Tumorska angiogeneza--ponovno vruca znanstvena tema.

Angiogenesis is the formation of new capillary blood vessels. It has a very important role not only in physiological conditions but in the process of malignant tumors growth. Weak muscular layer, chaotical branching and irregular shape, are the characteristics of newly formed tumorous vessels. The number and arrangement of blood vessels differ between benign and malignant tumors. Latest data suggesting that drugs inhibiting angiogenesis can stop growth of malignant tumors made the research on tumorous angiogenesis a hot topic recently. Although reliable in differentiating benign from malignant tumors, two-dimensional ultrasound with color and pulsed Doppler, can not make spatial image of vascular architecture. Three-dimensional (3D) ultrasound with color Doppler allows the investigator to have a three-dimensional architectural picture of tumorous vascular network, and according to the findings it is possible to detect malignant tumors even in doubtful cases.

Early ovarian cancer: 3-D power Doppler.

Transvaginal sonography plays an important role in the assessment of the morphology of ovarian lesions. However, the accuracy of the technique is limited due to the significant number of false-positive results. Color Doppler imaging and pulsed Doppler spectral analysis enable evaluation of ovarian tumor blood flow, analysis of the distribution of blood vessels, and quantitative measurement of blood flow velocity waveforms. These parameters increase the sensitivity and specificity of ultrasound evaluation of ovarian tumors. Unfortunately, there is no consensus as to which Doppler parameters and cutoff values are the most predictive of malignancy. Three-dimensional (3-D) power Doppler ultrasound provides a new tool to evaluate features of tumor vascularity. Three-dimensional ultrasound and 3-D power Doppler imaging in patients with "positive" findings on standard ultrasound tests, which encompass annual gray-scale transvaginal sonography followed by transvaginal color Doppler ultrasound in selected cases, represent a novel approach for early and accurate detection of ovarian cancer through screening. Combined evaluations of morphology and neovascularity by 3-D power Doppler ultrasound may improve early detection of ovarian carcinoma. Contrast-enhanced 3-D power Doppler sonography facilitates visualization of adnexal tumor vessels, which may aid in differentiating benign from malignant adnexal lesions.

The first three weeks assessed by transvaginal color Doppler.

Transvaginal color Doppler has made possible to study ovarian and uterine perfusion in non-pregnant and pregnant patients, thus advancing the understanding of the early human development. RI of follicular blood flow starts decreasing prior to ovulation reaching its nadir at ovulation. It is considered that apart from hormonal factors the angiogenesis is also involved. The mature corpus luteum shows increased blood flow velocity in relation to preovulatory follicle. Comparing RI values of luteal blood flow of normal and ectopic pregnancy no difference was found. But in threatened, incomplete and missed abortions the resistance and pulsatility indices were significantly higher than in normal pregnancy. The follow up of the luteal flow might have a prognostic value in a group of patients with threatened abortion. In women with spontaneous cycles the day preceding the ovulation impedance to uterine flow velocity starts decreasing. Alterations in flow velocity patterns of the radial and spiral arteries in spontaneous ovulatory cycles are paralleling blood flow dynamics of the uterine arteries. In stimulated cycles RI increases the day before ovulation in both the uterine arteries and their branches. It seems that endometrial perfusion presents more accurate noninvasive assay of uterine receptivity than uterine artery perfusion alone. Endometrial receptivity is maximum during the time of peak luteal function during which implantation is most likely to occur. During the pregnancy impedance to blood flow decrease from the main uterine to the spiral arteries as well as with the advancing gestational age. The spiral arteries in pregnancy become the vessels with completely different haemodynamic characteristics in relation to other arteries of uteroplacental circulation. Color Doppler adds new information on perfusion and pathophysiological changes connected with the ectopic trophoblast implantation.