Transvaginal Doppler study of uterine artery blood flow in in vitro fertilization-embryo transfer cycles

Drug intervention in early pregnancy after assisted reproductive technology

Implantation in humans is a complex, closely regulated, highly selective and relatively poorly understood process. Humans have the highest rate of miscarriage in mammals and various pharmacological manipulations have been used to minimize pregnancy losses in both spontaneous pregnancies and pregnancies resulting from assisted reproduction technology. The widespread application of protocols using numerous drugs in assisted reproduction treatment has led to an increasing number of pregnancies exposed to these drugs. The vast majority of these protocols have been based on data from a few observational and often retrospective clinical studies. This paper reviews the recent literature on drug interventions in early pregnancy after assisted reproduction treatment. It is concluded that there are still numerous issues about the safety of most drugs for both the women and their fetus. In many cases, the benefits are theoretical and the possible long-term side-effects are untested. There is an urgent need for more epidemiological studies and randomized controlled trials to explore the use, efficacy and side-effects of both old and new drugs in early pregnancy after assisted reproduction treatment.

Transrectal Doppler sonography of uterine blood flow during early pregnancy in mares

Transrectal color Doppler sonography was used for the noninvasive investigation of uterine blood flow in five mares. Both the left and right uterine arteries were scanned to obtain blood flow velocity waveforms during two consecutive estrous cycles and two early pregnancies in each mare. Blood flow was expressed as the time-averaged maximum velocity (TAMV) and the resistance index (RI). In all pregnancies the embryonic vesicle could be detected for the first time on Day 11 (day of ovulation: Day 0). No differences in mean TAMV and RI values of both uterine arteries were observed in comparison to the corresponding days of the estrous cycle until Day 11 of pregnancy (P>0.05). From Day 11 onwards, mean TAMV values were higher and mean RI values lower in pregnant mares than in cyclic mares (P<0.05). During the estrous cycle TAMV and RI values did not differ between the right and left uterine arteries (P>0.05). From Days 15 to 29 of pregnancy, TAMV values were consistently higher and RI values lower in the uterine artery ipsilateral to the conceptus and they had a more distinct rise and decline, respectively, compared to the contralateral uterine artery (P<0.05). The variance component estimates for the effect of mare on TAMV and RI values during pregnancy were 60 and 53%, respectively, and for the effect of day of pregnancy, they were 29 and 34%, respectively (P<0.0001). Within mares there were no significant differences between the two pregnancies with regard to blood flow (P>0.05). The results show that uterine blood supply increases in mares during the second week of pregnancy compared to cyclic mares. Furthermore there are individual variations in blood flow between mares.

Imaging the endometrium: are there predictors of uterine receptivity?

Ultrasound imaging technology brings new insight to cyclic changes in the endometrium and offers the potential to assess the probability of embryo implantation in natural and assisted reproduction cycles. However, the data reported are diverse and frequently conflict in their analysis and conclusions. This review examines imaging techniques used for endometrial evaluation, including grey-scale ultrasonography and colour-flow, power-flow, and spectral Doppler interrogation of the uterine vasculature. New techniques being used for uterine assessment, such as computer-assisted image analysis, three-dimensional ultrasonography, and magnetic resonance imaging, are also discussed. Each of these techniques is under active investigation and has the potential to provide rapid, noninvasive endometrial evaluation. Currently, there is reasonable certainty that women with heterogeneous endometrial linings of less than 6 mm will rarely conceive, and that endometrial contractions, or lack thereof, play some role in the successful establishment of pregnancy, even though this role has not yet been identified. Given the set of new imaging technologies available, it is feasible to expect that visual assessments will someday be used as predictors of uterine receptivity.

Comparison of uterine and spiral artery blood flow in women with unexplained and tubal infertility

OBJECTIVE

To evaluate the possible difference in uterine and spiral artery impedance to blood flow among women with unexplained and tubal infertility during spontaneous and gonadotropin-stimulated cycles.

METHODS

We prospectively compared uterine and spiral artery pulsatility index and peak systolic velocity in a longitudinal study in women with either unexplained infertility (n = 20) or tubal infertility (n = 18). Measurements of uterine and spiral artery impedance were taken on days 11-12, 16-17 and 21-23 of the spontaneous cycle and on days 1, 5 and 10 during gonadotropin stimulation. In addition, measurements were taken on the days of oocyte pick-up and embryo transfer.

RESULTS

A clinical pregnancy was achieved in 8/20 (40%) women with unexplained and 6/18 (33.3%) women with tubal infertility with in-vitro fertilization treatment. There were no differences in the uterine artery pulsatility index or peak systolic velocity during the spontaneous or the in-vitro fertilization cycle between the two groups. The impedance to blood flow in the uterine or spiral artery did not differ between women conceiving with in-vitro fertilization-embryo transfer and those who did not. However, the spiral artery pulsatility index on the 5th day of gonadotropin stimulation was significantly lower among women with unexplained infertility (0.96 +/- 0.25) compared to women with tubal infertility (1.24 +/- 0.30; P < 0.05), but on the other days of gonadotropin stimulation the spiral artery pulsatility index and peak systolic velocity were similar.

CONCLUSIONS

Impaired uterine or spiral artery blood flow is not an important factor in unexplained infertility.

Cycle-to-cycle variation in utero-ovarian hemodynamic indices in ovarian stimulation and natural cycles of the same women and its effect on the outcome of assisted reproduction treatment

OBJECTIVE

To investigate the blood flow parameters between cycles of the same women to assess whether parameters predicting a successful pregnancy in a stimulation cycle could be used to determine the outcome of subsequent natural cycles.

DESIGN

A prospective study.

SETTING

Assisted reproduction unit, the University of Hong Kong.

PATIENT(S)

Fifty-eight IVF cycles and 40 natural cycles were evaluated.

INTERVENTION(S)

Assessments of the utero-ovarian pulsatility indices (PIs), resistance indices (RIs), and endometrial color signals.

RESULT(S)

In IVF cycles, the pregnancy rate (27%) was similar to that in frozen-thawed embryo transfer (FET) (28%) cycles. The utero-ovarian PIs and RIs in IVF cycles were significantly lower than those in the natural cycles. There was a significant correlation between the uterine PI in stimulation cycles and that in natural cycles. In IVF cycles, the pregnancy rate declined significantly when the uterine PI was >2.70 and the RI was >0.9. In FET cycles, no decline in pregnancy rate was seen. Conceptional FET cycles showed significantly higher uterine PI, uterine RI, and endometrial color signals compared with conceptional IVF cycles.

CONCLUSION(S)

Hemodynamic parameters in stimulation cycles are different from those in natural cycles, and the values of various parameters in predicting pregnancy are also different.

Endometrial vascularity and ongoing pregnancy after IVF

BACKGROUND

Embryo transfer is prone to failure.

AIM

To investigate whether endometrial vascularity influences in vitro fertilization (IVF) outcome.

METHODS

Total 144 patients receiving IVF (conventional or microinjection) were assessed with color and power Doppler on the day of embryo transfer: age, IVF type, number and quality of embryos, endometrial thickness and aspect, mean uterine PI, uterine notch, type of endometrial vascularity (peripheral or sub- and intra-endometrial), and pregnancy involving second trimester were recorded.

RESULTS

27 (18.7%) pregnancies were obtained. By univariate analysis, two parameters were significant: high frequency of uterine notch (P = 0.03) and peri-endometrial vascularity (P = 0.012) in the group of failures. Multivariate analysis by logistic regression clearly showed that the absence of sub- and intra-endometrial color signal decreased the chances of pregnancy eight-fold odds ratio (OR) = 0.14 [CI: 0.029-0.68].

CONCLUSION

In this limited series, the presence of sub- and intra-endometrial vascularity on the day of transfer seemed to be mandatory for obtaining an ongoing pregnancy.

[Contribution of ovarian and uterine color Doppler in medically assisted reproduction techniques (ART)]

Along the menstrual cycle and during pregnancy, small blood vessels proliferate within the uterus and the ovulating ovary. Angiogenic factors such as VEGF are involved in this phenomenon. In the ovulating ovary, neo-angiogenesis spreads progressively inside the dominant follicle wall and plays a role in the maintenance of the corpus luteum, under the influence of LH (or HCG during pregnancy). In ART, the measure of the blood flow is interesting since it correlates to the number and quality of harvested oocytes. Follicle hypoxia may impair chromosomal organization and separation within the oocyte. This neo-angiogenesis is also important in endometrium, in particular for embryo implantation. Ultrasounds with Doppler allow to estimate the endometrial receptivity, especially in IVF cycles. It is assumed that chance for ongoing pregnancy is almost zero if: endometrial thickness is < 8 mm; uterine pulsatility index (PI) is > 3. Doppler ultrasounds are a useful and even mandatory complement to standard vaginal ultrasonoghraphy in ART. It can be viewed as an indicator of the endometrial and follicular "well-being".

Measurement of endometrial tissue blood flow: a novel way to assess uterine receptivity for implantation

OBJECTIVE

To assess endometrial receptivity in terms of endometrial tissue blood flow (ETBF) measured hysterofiberscopically by laser blood-flowmetry, and to examine the technique's effectiveness in an in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) program.

DESIGN

A prospective clinical study.

SETTING(S)

IVF program in a university hospital.

PATIENT(S)

A total of 75 infertile women with normal menstrual cycles undergoing IVF/ICSI.

INTERVENTION(S)

ETBF, conventional ultrasonographic, endocrinologic, and histologic parameters for receptivity and immunoreactivity for vascular endothelial growth factor (VEGF) in endometrium were assessed between days 4 and 6 of the luteal phase in a spontaneous menstrual cycle. Then all patients underwent IVF/ICSI.

MAIN OUTCOME MEASURE(S)

Achievement of clinical pregnancy by IVF/ICSI.

RESULT(S)

ETBF, VEGF expression, and the number of embryos were significantly higher in the women who became pregnant than in those who did not. By stepwise multiple logistic regression, significant predictors of pregnancy were the number of embryos and ETBF but not conventional receptivity markers. The rate of pregnancy was significantly higher in women with ETBF values of at least 29 mL/min per 100 grams of tissue than in women with lower values (42 vs. 15% in 36 and 39 women, respectively). ETBF was significantly greater in morphologically normal than abnormal uteri. In normal uteri, ETBF was greatest in the fundus. Correspondingly, in normal uteri 85% of gestational sacs were implanted in the fundus.

CONCLUSION(S)

ETBF is superior to conventional parameters for determining endometrial receptivity for implantation.

Assessing uterine receptivity in 2001: ultrasonographic glances at the new millennium

The understanding and control of embryo implantation represents the major challenge for assisted reproductive technologies. Along with developments in basic research and efforts to optimize embryo quality, the improvement of noninvasive and reliable methods to assess uterine receptivity constitutes an important step toward meeting such a challenge. Today, ultrasound-based approaches to evaluate endometrial echogenicity and uterine perfusion and contractility are available for practical use. Increasing evidence indicates that echogenic patterns of the endometrium reflect histologic processes that are involved in the establishment of receptivity. This constitutes a possible explanation for the reported association between premature hyperechogenic patterns of the endometrium and poor implantation rates. Nevertheless, additional studies aiming at correlating further morpho-biochemical events in the endometrium with its echogenicity patterns are needed. Further, developments in vascular assessment by Doppler, Doppler-related, and vascular detection technologies will also be instrumental in monitoring and improving vascular changes that lead to uterine receptivity. Finally, data supporting the hypothesis that uterine contractility, as visualized by ultrasound, influences in vitro fertilization-embryo transfer (IVF-ET) pregnancy rates encourage further investigation on both the regulation and control of uterine contractions. This article discusses some of the advantages and limitations of ultrasonographic assessments of uterine receptivity in the perspective of the new millennium.

Uterine perfusion and hormonal pattern in patients with polycystic ovary syndrome

PURPOSE

To evaluate whether polycystic ovary syndrome (PCOS) patients with different pulsatility index (PI) of uterine artery showed differences in their hormonal pattern.

METHODS

Eighty-eight PCOS-affected patients and 15 controls were submitted to Doppler flow measurement of uterine artery; LH, FSH PRL, estradiol, and androgens concentration determination; and BMI evaluation during early follicular phase.

RESULTS

The mean PI of uterine artery of PCOS patients was significantly higher than control group (2.97 +/- 0.9 vs. 1.89 +/- 0.2 respectively). The distribution of the PI'values was significantly different in the PCOS-affected patients and in control group. The plasma levels of DHEAS and BMI were significantly higher in PCOS patients with PI > or = 3 than in PCOS patients with PI < 3.

CONCLUSION

High resistance in the uterine artery is present in PCOS patients, but a wide range PI values of uterine artery is present. BMI and DHEAS seem to be factors interfering with uterine perfusion.

Haemodynamic evaluation of tubal and male factors of infertility in natural and ovarian stimulation cycles

PURPOSE

To determine the haemodynamic parameters in women with tubal and male factors of infertility and to investigate the effect of ovarian stimulation on the blood flow indices of the uterine and ovarian arteries.

METHODS

Prospective evaluation of the pulsitility index (PI) and resistance index (RI) of the uterine and ovarian arteries in the tubal and male factors of infertility was done. Comparisons were made between the natural and ovarian stimulation cycles.

RESULTS

In natural cycles, uterine PI was 3.55 +/- 1.39 and RI was 0.95 +/- 0.05 in tubal infertility. These were significantly lower (uterine PI = 4.13 +/- 0.08; uterine RI = 0.99 +/- 0.06) than the corresponding indices in patients with male factor infertility. After ovarian stimulation in tubal factor, uterine PI and RI were 2.62 +/- 0.73 and 0.88 +/- 0.08 and were similar (PI = 2.55 +/- 0.62, RI = 0.87 +/- 0.06) to male factor infertility.

CONCLUSIONS

The data points to measurable differences in the uterine PI and RI between the tubal infertility and male infertility in the natural cycles. These differences were abolished after ovarian stimulation.

Endometrial receptivity in an in vitro fertilization program as assessed by spiral artery blood flow, endometrial thickness, endometrial volume, and uterine artery blood flow

OBJECTIVE

To investigate the role of sonographic parameters in assessing endometrial receptivity in an in vitro fertilization (IVF) program.

DESIGN

Prospective clinical study.

SETTING

University setting.

PATIENT(S)

One hundred thirty-five patients in our IVF program, selected prospectively on the day of oocyte retrieval.

INTERVENTION(S)

Transvaginal ultrasound examination was performed before oocyte collection.

MAIN OUTCOME MEASURE(S)

Association between implantation rate and spiral artery blood flow (primary outcome measure) and between implantation rate and endometrial measurements as well as uterine artery blood flow (secondary outcome measures).

RESULT(S)

Overall implantation rate was 23.7% per cycle. Subendometrial blood flow was detected in 113 (83.7%) cases, with pregnancy occurring in 21.2%. Mean spiral artery pulsatility index values were 1.12 +/- 0.28 and 1.21 +/- 0.27 for nonconception and conception cycles, respectively. Nondetectable spiral artery blood flow was not associated with a lower implantation rate. Neither endometrial thickness nor endometrial volume was correlated with the likelihood of successful implantation. Minimum endometrial thickness and volume associated with pregnancy were 6.9 mm and 1.59 mL, respectively.

CONCLUSION(S)

Neither Doppler sonography of the spiral or uterine arteries nor measurement of the endometrial thickness or volume allowed a reliable prediction of subsequent IVF outcome.

Effect of an in vitro fertilization program on serum CA 125, tumor-associated trypsin inhibitor, free beta-subunit of human chorionic gonadotropin, and common alpha-subunit of glycoprotein hormones

OBJECTIVE

To investigate the impact of an IVF program on serum levels of tumor markers CA 125, tumor-associated trypsin inhibitor, free hCG beta-subunit, and free glycoprotein hormone alpha-subunit.

DESIGN

A prospective controlled clinical study.

SETTING

Outpatient university infertility clinic.

PATIENT(S)

Seventy-one infertile patients (with tubal occlusion, pelvic endometriosis, or unexplained infertility) undergoing IVF and nine control women with regular menstrual cycles.

INTERVENTION(S)

Serial blood sampling before, during, and after IVF, or during one ovulatory menstrual cycle in the controls.

MAIN OUTCOME MEASURE(S)

Serum levels of CA 125, tumor-associated trypsin inhibitor, hCG-beta, and glycoprotein hormone-alpha.

RESULT(S)

Before IVF, all tumor markers were within the normal range except for CA 125, which was elevated in patients with endometriosis. IVF led to significant increases in CA 125 and glycoprotein hormone-alpha that differed from the changes seen during normal menstrual cycles. The luteal phase increase in CA 125 correlated with levels of E(2) and P and the number of follicles. Two months after IVF, levels of CA 125 were 12% higher than levels before treatment. Tumor-associated trypsin inhibitor and hCG-beta revealed no cyclicity.

CONCLUSION(S)

An IVF regimen increased the release of CA 125 and glycoprotein hormone-alpha. The CA 125 elevation after IVF implies a persistent effect of ovarian hyperstimulation on CA 125 release.

Prediction of pregnancy rate of in vitro fertilization and embryo transfer in women aged 40 and over with basal uterine artery pulsatility index

PURPOSE

The purpose was to determine the effect of basal uterine perfusion on the pregnancy rates of in vitro fertilization and embryo transfer (IVF-ET) in women aged 40 and above.

METHODS

A total of 47 patient aged 40 and over underwent IVF-ET. The conception cycles and the nonconception cycles were compared.

RESULTS

Of the 47 patients, 4 patients were pregnant (8.5%). The mean age, basal follicle stimulating hormone (FSH), basal estradiol (E2) level, antral follicle count (AFC), number of ampoules of gonadotropin used, E2 levels and endometrial thickness on the day of human chorionic gonadotropin (hCG) administration, number of retrieved and fertilized oocytes, and number of transferred embryos were not statistically significant between the conception and nonconception cycles. However, the basal uterine artery pulsatility index (UA PI) was significantly lower in the conception cycles (P < 0.001). The receiver operating characteristics (ROC) curve analysis for basal FSH, AFC, and basal UA PI in predicting the pregnancy rate of IVF in patients aged > or = 40 were demonstrated. The best prediction rate was achieved by a pulsatility index cutoff of < 2.0 for a receptive uterus.

CONCLUSIONS

Increased uterine perfusion in the early follicular phase enhanced the pregnancy rate of IVF in women aged 40 and above. It is therefore essential that patients aged > or = 40 with poor basal uterine perfusion should be identified early in the early follicular phase of the menstrual cycle to apply appropriate intervention to improve the uterine circulation for the subsequent chance of pregnancy.

Predicting the histologic dating of an endometrial biopsy specimen with the use of Doppler ultrasonography and hormone measurements in patients undergoing spontaneous ovulatory cycles

OBJECTIVE

To examine the relation between uterine blood flow and endometrial thickness on transvaginal Doppler ultrasonography, serum E2 and progesterone levels, and the histologic dating of an endometrial biopsy specimen obtained in the midluteal phase of a spontaneous cycle.

DESIGN

Prospective clinical study.

SETTING

A tertiary care infertility center.

PATIENT(S)

One hundred fifty-nine patients with normal menstrual cycles.

INTERVENTION(S)

Transvaginal Doppler ultrasonographic evaluation of uterine blood flow and endometrial thickness, determination of serum concentrations of E2 and progesterone, and endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Resistance index, pulsatility index, serum E2 and progesterone levels, endometrial thickness, and histologic dating of the endometrium.

RESULT(S)

One hundred thirteen (71%) of the endometrial biopsy specimens showed complete secretory transformation and thus were classified as "in phase," and 46 (29%) of the specimens lacked some or all of the criteria for secretory transformation and thus were classified as "out of phase." There was no statistically significant difference between the in phase and out of phase groups with regard to patient age, endometrial thickness, serum hormone levels, or resistance index. The pulsatility index was significantly higher in the in phase group. The overall predictive value of the studied parameters was only 64% (sensitivity, 57%; specificity, 66%).

CONCLUSION(S)

Doppler ultrasonographic evaluation of uterine blood flow and measurement of hormone concentrations cannot be used to predict the histologic dating of an endometrial biopsy specimen obtained in the midluteal phase of a spontaneous cycle.

Effect of chronic administration of cabergoline on uterine perfusion in women with polycystic ovary syndrome

OBJECTIVE

To confirm whether patients with polycystic ovary syndrome (PCOS) have a reduction in uterine perfusion and to verify whether chronic administration of cabergoline can decrease this high vascular resistance.

DESIGN

Prospective randomized trial.

SETTING

Endocrinological Centre of the Department of Obstetrics and Gynecology, University of Cagliari, Cagliari, Italy.

PATIENT(S)

Thirty patients were enrolled in the study: 20 affected by PCOS and 10 healthy controls. Patients with PCOS were randomly assigned to one of two treatments for 3 months: oral administration of cabergoline (0.5 mg) every week or oral administration of placebo every week.

INTERVENTION(S)

All patients underwent transvaginal ultrasonography associated with Doppler flow measurement of the uterine artery, and serum hormone concentrations were determined during the early follicular phase. In women with PCOS, Doppler flow measurement and hormonal assessment were repeated in the early follicular phase of the third month of treatment.

MAIN OUTCOME MEASURE(S)

Pulsatility index of the uterine artery before and during treatment.

RESULT(S)

The mean pulsatility index of the uterine artery in patients with PCOS was significantly higher than that of the control group (3.29+/-0.5 and 2.01+/-0.2, respectively). Patients with PCOS treated with cabergoline showed a significant increase in uterine perfusion, with a pulsatility index of 3.14+/-0.6 before and 2.39+/-0.5 during the treatment. No difference was found in patients with PCOS treated with placebo.

CONCLUSION(S)

Patients with PCOS have high resistance in the uterine arteries, but chronic administration of cabergoline can increase uterine perfusion.

Transrectal color Doppler sonography of the A. uterina in cyclic mares

Color Doppler ultrasound was used transrectally in 6 mares to locate both the left and right Aa. uterinae and to obtain flow velocity waveforms at defined times (Days 0, 5, 10, 15 and 20) during 4 estrous cycles. Blood flow reflected by the resistance index (RI) was determined for both arteries on 120 occasions. As there was no significant difference and a high correlation in the RI values between the left and right arteries (paired Student's t-test, correlation coefficient r > 0.94; P < 0.05), the average RI value was used for subsequent analyses. There were correlations between RI values, mares and day of estrous cycle (P < 0.0001). The mean RI was higher (P < 0.05) in the 2 multiparous mares (age, 12 to 13 yr) than in the 4 younger maiden mares (age, 6 to 10 yr). During the estrous cycle mean RI values on Day 0 (day of ovulation) and Day 10 were higher (P < 0.05) than on Days 5, 15 and 20, whereas between estrous cycles within mares no differences (P > 0.05) could be measured. The results suggest that transrectal Color Doppler sonography is a noninvasive method for examining differences in impedance to uterine blood flow between different mares and cycle periods.

Evidence of interplay between plasma endothelin-1 and 17 beta-estradiol in regulation of uterine blood flow and endometrial growth in infertile women

OBJECTIVE

To determine the effects of gonadotropin-induced ovarian stimulation on the plasma levels of endothelin-1 as well as on uterine blood flow and endometrial thickness.

DESIGN

Controlled cross-over clinical study.

SETTING

Academic research environment.

PATIENT(S)

Eighteen volunteer infertile women (31.4 +/- 2.5 years, mean +/- SE) participating in an IVF-ET program.

INTERVENTION(S)

Transvaginal Doppler ultrasound was performed and blood samples were collected 4 days after the LH surge in a spontaneous cycle and 4 days after hCG administration in a subsequent gonadotropin-stimulated cycle.

MAIN OUTCOME MEASURE(S)

Plasma levels of E2, P, and endothelin-1; uterine artery pulsatility index; and endometrial thickness.

RESULT(S)

Stimulated cycles were associated with significantly higher E2 levels (101.0 +/- 10.2 versus 723.5 +/- 57.3 pg/mL [conversion Factor to SI unit, 3.671]; spontaneous versus stimulated), thicker endometrium (9.2 +/- 2.5 versus 11.4 +/- 2.9 mm), and lower endothelin-1 levels (2.5 +/- 0.1 versus 2.1 +/- 0.1 pg/mL [conversion factor to SI unit, 0.4]) and pulsatility index (3.22 +/- 0.12 versus 2.63 +/- 0.08) than spontaneous cycles. Endothelin-1 correlated negatively with E2 (r = -0.38), but not with P or pulsatility index. Differences in endothelin-1 and endometrial thickness between spontaneous and stimulated cycles correlated negatively (r = -0.56) with each other.

CONCLUSION

Our results suggest an inhibitory role for E2 in the release of endothelin-1, which could be a factor in the regulation of uterine and endometrial blood flow.