Sequential use of letrozole and gonadotrophin in women with poor ovarian reserve: a randomized controlled trial.

Sequential use of letrozole and human menopausal gonadotrophin (HMG) was compared with HMG only in poor ovarian responders undergoing IVF. Patients (n=53) with less than four oocytes retrieved in previous IVF cycles or less than five antral follicles were randomized to either letrozole for 5days followed by HMG or HMG alone. The letrozole group had lower dosage of HMG (P<0.001), shorter duration of HMG (P<0.001) and fewer oocytes (P=0.001) when compared with controls. Live-birth rate was comparable with a lower miscarriage rate in the letrozole group (P=0.038). Serum FSH concentrations were comparable in both groups except on day 8, while oestradiol concentrations were all lower in the letrozole group from day 4 (all P<0.001). Follicular fluid concentrations of testosterone, androstenedione, FSH and anti-Müllerian hormone were higher in the letrozole group (P=0.009, P=0.001, P=0.046 and P=0.034, respectively). Compared with HMG alone, sequential use of letrozole and HMG in poor responders resulted in significantly lower total dosage and shorter duration of HMG, a comparable live-birth rate, a significantly lower miscarriage rate and a more favourable hormonal environment of follicular fluid. The management of poor ovarian responders or women with poor ovarian reserve in IVF is controversial. The use of letrozole has been studied; however, results are inconsistent. This randomized trial studied the sequential use of letrozole and gonadotrophin compared with gonadotrophin alone in poor responders undergoing IVF. The sequential use of letrozole and gonadotrophin led to a significantly lower dosage and shorter duration of gonadotrophin use, significantly fewer oocytes, comparable live-birth rate, a significantly lower miscarriage rate and a more favourable hormonal environment at a lower cost.

Changes in endometrial and subendometrial blood flow in IVF.

A good blood supply to the endometrium is usually considered as an essential requirement for implantation. Endometrial and subendometrial blood flow was evaluated on the days of human chorionic gonadotrophin (HCG) administration and embryo transfer and the percentage change in endometrial and subendometrial blood flow between these 2 days was assessed as a predictor of pregnancy during IVF treatment. A three-dimensional (3D) ultrasound examination with power Doppler was performed in 293 patients undergoing the first IVF cycle to determine endometrial thickness, endometrial volume, vascularization index, flow index and vascularization flow index of endometrial and subendometrial regions on the days of HCG and embryo transfer. Patients in non-pregnant and pregnant groups had comparable endometrial thickness, endometrial volume and 3D power Doppler flow indices of endometrial and subendometrial regions measured on either day. Percentage changes in endometrial and subendometrial 3D power Doppler flow indices were also similar. In conclusion, endometrial and subendometrial blood flow on the days of HCG and embryo transfer and the percentage change in endometrial and subendometrial blood flows between these 2 days were not predictive of pregnancy in IVF treatment.

Ovarian stromal blood flow following clomiphene citrate challenge test in infertile women.

PURPOSE: To compare ovarian stromal blood flow indices in the follicular phase and after clomiphene citrate (CC) in infertile women. METHODS: Pulsatility index (PI), resistance index (RI), and peak systolic blood flow velocity (PSV) of ovarian stromal vessels were determined by spectral Doppler analysis in the early follicular phase and on day 10 after CC. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol concentrations were determined. RESULTS: A total of 69 infertile women were included in the analysis. No significant differences in the average PI, RI, and PSV of ovarian stromal blood flow were demonstrated in the follicular phase and after CC despite a significant increase in serum estradiol concentration after CC. Serum FSH concentration was similar in the follicular phase and after CC, while serum LH concentration was significantly higher after CC. In the right ovary, ovarian stromal blood flow was absent in 13 (18.8%) patients in the follicular phase and in 6 (8.7%) patients after CC, but the difference did not reach statistical significance. In the left ovary, ovarian stromal blood flow was absent in 13 (18.8%) and 12 (17.4%) patients in the follicular phase and after CC, respectively. CONCLUSION: Ovarian stromal blood flow indices were similar in the follicular phase and after CC.

The role of endometrial blood flow measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during in vitro fertilization treatment.

Ultrasound examination of the endometrium is a commonly used non-invasive method to assess endometrial receptivity during in vitro fertilization (IVF) treatment. A good blood supply towards the endometrium is usually considered to be an essential requirement for implantation and therefore assessment of endometrial blood flow in IVF treatment has attracted a lot of attention in recent years. Doppler study of uterine arteries does not reflect the actual blood flow to the endometrium. Endometrial and subendometrial blood flows can be more objectively and reliably measured with three-dimensional power Doppler ultrasound. However, conflicting results are reported with regard to their role in the prediction of pregnancy in IVF treatment. Relevant studies in the literature differed in patients' characteristics, the day of ultrasound examination and the selection of the subendometrial region. As the degree of change in endometrial perfusion from the late follicular phase to the early luteal phase may be a more important determinant of endometrial receptivity, further studies should be conducted to determine the change in endometrial and subendometrial blood flows from late follicular phase to early luteal phase in order to delineate the role of endometrial and subendometrial blood flows in predicting IVF outcome.

Comparison of 2-dimensional, 3-dimensional, and vascular ultrasonographic parameters for endometrial receptivity between 2 consecutive stimulated in vitro fertilization cycles.

OBJECTIVE: We compared the ultrasonographic parameters for endometrial receptivity between 2 consecutive in vitro fertilization (IVF) cycles in the same patients. METHODS: Patients who had undergone 2 in vitro fertilization cycles between November 2002 and December 2004 were recruited. A 3-dimensional ultrasonographic examination with power Doppler imaging was performed on the day of oocyte retrieval to determine the endometrial thickness, endometrial pattern, pulsatility and resistive indices of uterine vessels, endometrial volume, vascularization index, flow index, and vascularization flow index of endometrial and subendometrial regions. RESULTS: Of 662 patients, 95 (14.4%) underwent 2 consecutive cycles using the same stimulation regimen during the study period. There were no significant differences in these ultrasonographic parameters between the first and second cycles. The intraclass correlation coefficient (ICC) for endometrial volume was significantly higher than that of other ultrasonographic parameters. The ICC for the endometrial thickness, uterine pulsatility index, and endometrial 3-dimensional power Doppler flow indices were similar. CONCLUSIONS: Ultrasonographic parameters for endometrial receptivity were comparable in the 2 consecutive stimulated cycles. The endometrial volume had the highest ICC among these ultrasonographic parameters and was most reproducible between 2 cycles.

A randomized comparison of side effects and patient convenience between Cyclogest suppositories and Endometrin tablets used for luteal phase support in IVF treatment.

OBJECTIVE: This study compared side effects and patient convenience of vaginal progesterone suppositories (Cyclogest) and vaginal progesterone tablets (Endometrin) used for luteal phase support in in vitro fertilization/embryo transfer (IVF/ET) cycles using pituitary downregulation. STUDY DESIGN: One hundred and thirty-two infertile patients were randomized on the day of ET by a computer-generated randomization list in sealed envelopes to receive either Cyclogest 400mg or Endometrin 100mg twice daily for 14 days. On days 6 and 16 after ET, they rated side effects and patient convenience into four grades: none, mild, moderate and severe by completing a questionnaire. RESULTS: No significant differences in perineal irritation were found on days 6 and 16 after ET between the two groups, although there was a trend of fewer patients with perineal irritation in the Endometrin group. Significantly more patients in the Endometrin group had difficulty of administration on day 6 after ET. There were no differences in the hormonal profile on day 6 after ET and IVF outcomes between the two groups. CONCLUSION: There was no difference in perineal irritation after the use of Cyclogest suppositories or Endometrin tablets for luteal phase support although more patients found administration of Endometrin tablets difficult.

Endometrial and subendometrial vascularity is higher in pregnant patients with livebirth following ART than in those who suffer a miscarriage.

BACKGROUND: Blood flow towards the peri-implantation endometrium may have effects on miscarriage and live birth following assisted reproduction treatment, in addition to its role in implantation. METHODS: Three-dimensional ultrasound examination with power Doppler was performed on the day of oocyte retrieval in stimulated IVF cycles and on LH + 1 day in frozen thawed-embryo transfer (FET) cycles to measure endometrial thickness, endometrial pattern, uterine artery Doppler flow indices, endometrial volume, vascularization index (VI), flow index (FI), vascularization flow index (VFI) of endometrial and subendometrial regions. RESULTS: In stimulated IVF cycles, 45 (28.0%) out of 161 pregnant patients subsequently miscarried. Patients in the live birth group had significantly higher endometrial VI and VFI and subendometrial VI, FI and VFI, when compared with those in the miscarriage group. In a multiple logistic regression analysis, only endometrial VI was significantly associated with the chance of live birth with an odds ratio of 1.384 [95% confidence interval (CI) 1.025-1.869, P = 0.034]. For FET cycles, patients in the live birth group had significantly higher endometrial VFI, subendometrial VI and VFI than those in the miscarriage group. CONCLUSIONS: Endometrial and subendometrial vascularity was significantly higher in pregnant patients with live birth following stimulated IVF and FET treatment than in those who suffered a miscarriage.

Comparison of endometrial and subendometrial blood flows among patients with and without hydrosalpinx shown on scanning during in vitro fertilization treatment.

OBJECTIVE: To compare endometrial and subendometrial blood flows among patients with and without hydrosalpinx (HSP) during in vitro fertilization treatment as measured by a three-dimensional power Doppler ultrasound. DESIGN: A prospective observational study. SETTING: A tertiary assisted-reproduction unit. PATIENT(S): Twenty-one patients with HSP were compared with 42 matched controls without HSP. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Endometrial thickness, endometrial pattern, endometrial volume, pulsatility index (PI) and resistance index (RI) of uterine vessels, and the vascularization index (VI), flow index (FI), and vascularization flow index (VFI) of endometrial and subendometrial regions were measured on the day of oocyte retrieval. RESULT(S): The proportion of the non-multilayered endometrial pattern was significantly higher in the HSP group than in the non-HSP group. Patients in the HSP group had significantly lower endometrial and subendometrial VI and VFI. Endometrial thickness, endometrial volume, uterine PI, uterine RI, and endometrial and subendometrial FI were similar between the two groups. No significant differences were observed in endometrial and subendometrial VI, FI, and VFI among patients with unilateral and bilateral HSP. CONCLUSION(S): A change in endometrial pattern and a decrease in endometrial and subendometrial blood flows may be the reasons for impaired implantation in patients with HSP.

Endometrial, subendometrial, and ovarian stromal blood flow in patients treated with two different doses of recombinant human chorionic gonadotropin.

The effects of two different doses of recombinant hCG on blood flow to the uterus and ovary on the day of oocyte retrieval were studied by three-dimensional Doppler ultrasonography in 60 women during IVF treatment. There were no differences in all the indices of endometrial, subendometrial, and ovarian stromal blood flow in women who had received 250 microg or 500 microg of recombinant hCG for final oocyte maturation.

Ovarian stromal vascularity is not predictive of ovarian response and pregnancy.

The role of ovarian stromal vascularity in the prediction of the ovarian response and pregnancy in infertile women was evaluated by comparing age of women, body mass index (BMI), basal FSH concentration, antral follicle count (AFC) and ovarian stromal vascularity indices measured by three-dimensional power Doppler ultrasound. A total of 111 women in their first IVF cycle were analysed. They were aged <40 years with basal FSH concentration <10 IU/l on recruitment for IVF treatment. AFC, mean ovarian volume and mean ovarian 3D power Doppler flow indices were determined on day 2 of the treatment cycle prior to a standard regimen of ovarian stimulation. Ovarian response was represented by the number of oocytes, serum oestradiol, the duration and dosage of gonadotrophins. AFC achieved the best predictive value in relation to the number of oocytes obtained, followed by age of women and BMI. Basal FSH concentration was the only predictive factor for the duration and dosage of gonadotrophin used. Mean ovarian 3D power Doppler flow indices were not predictive of pregnancy in a multiple logistic regression analysis. Ovarian 3D power Doppler flow indices measured after pituitary down-regulation were not predictive of the ovarian response and pregnancy in the IVF treatment.

The role of endometrial and subendometrial vascularity measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during frozen-thawed embryo transfer cycles.

BACKGROUND: A good blood supply to the endometrium is usually considered as an essential requirement for implantation. OBJECTIVE: The aim of this study was to evaluate the role of endometrial and subendometrial vascularity in the prediction of pregnancy during frozen-thawed embryo transfer (FET) cycles. METHODS: Women undergoing FET in natural or clomiphene-induced cycles after the first stimulated IVF treatment were recruited. A three-dimensional (3D) ultrasound examination with power Doppler was performed 1 day after the LH surge to determine endometrial thickness, endometrial pattern, pulsatility index (PI) and resistance index (RI) of uterine vessels, endometrial volume, vascularization index, flow index and vascularization flow index of endometrial and subendometrial regions. RESULTS: Women in the pregnant group were significantly younger and used less gonadotrophins in their stimulated cycle. Endometrial thickness, endometrial volume, endometrial pattern, uterine PI, uterine RI, endometrial and subendometrial 3D power Doppler flow indices were similar between the nonpregnant and the pregnant groups. The age of women was the only predictive factor for pregnancy. Receiver operating characteristic curve analysis revealed that the area under the curve was around 0.5 for all ultrasound parameters for endometrial receptivity. CONCLUSION: Vascularity of endometrial and subendometrial layers measured by 3D power Doppler ultrasound is not a good predictor of pregnancy in FET cycles if measured at one time point only.

The role of endometrial and subendometrial blood flows measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during IVF treatment.

BACKGROUND: A good blood supply towards the endometrium is usually considered to be an essential requirement for implantation. We aimed to evaluate the role of endometrial and subendometrial blood flows in the prediction of pregnancy during IVF treatment. METHODS: Patients undergoing the first IVF cycle were recruited. A three-dimensional (3D) ultrasound examination with power Doppler was performed on the day of oocyte retrieval to determine endometrial thickness, endometrial pattern, pulsatility index (PI) and resistance index (RI) of uterine vessels, endometrial volume, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) of endometrial and subendometrial regions. RESULTS: Uterine RI, endometrial VI and VFI were significantly lower in the pregnant group than the non-pregnant group. There was a non-significant trend of higher implantation and pregnancy rates in patients with absent endometrial or subendometrial blood flow. The number of embryos replaced and endometrial VI were the only two predictive factors for pregnancy. Receiver operator characteristic curve analysis revealed that the area under the curve was approximately 0.5 for all ultrasound parameters for endometrial receptivity. CONCLUSION: Endometrial and subendometrial blood flows measured by 3D power Doppler ultrasound were not good predictors of pregnancy if they were measured at one time-point during IVF treatment.

Factors affecting endometrial and subendometrial blood flow measured by three-dimensional power Doppler ultrasound during IVF treatment.

BACKGROUND: No information exists in the literature regarding the factors affecting the blood flow towards the endometrial and subendometrial regions during IVF treatment. METHODS: We examined the effect of women's age, their smoking habits, their type of infertility (i.e. primary or secondary) and parity, causes of infertility and serum estradiol (E2) concentration on endometrial and subendometrial blood flows as measured by a three-dimensional (3D) power Doppler ultrasound during IVF treatment. All patients received a standard long protocol of ovarian stimulation and serum E2 concentration was determined on the day of hCG. 3D ultrasound examination with power Doppler was performed on the day of oocyte collection to determine vascularization index (VI), flow index (FI) and vascularization flow index (VFI) of endometrial and subendometrial regions. RESULTS: The age of women, their smoking habits, their types of infertility and parity and causes of infertility had no effect on the endometrial and subendometrial 3D power Doppler flow indices. There was a negative correlation between serum E(2) concentration and endometrial FI (r = -0.109; P = 0.006). CONCLUSIONS: Endometrial blood flow in IVF treatment was negatively affected by serum E2 concentration only.

Ovarian stromal blood flow in the prediction of ovarian response during in vitro fertilization treatment.

BACKGROUND: This study evaluated the role of ovarian stromal blood flow in the prediction of the ovarian response of infertile women by comparing age of women, body mass index (BMI), basal FSH concentration, antral follicle count (AFC) and ovarian stromal blood flow indices measured by power Doppler in two-dimensional ultrasound. Patients were aged <40 years with basal FSH <10 IU/l on recruitment for IVF treatment. METHODS: All received a standard regimen of ovarian stimulation in their first IVF cycle. AFC, pulsatility index, resistance index and peak systolic blood flow velocity of ovarian stromal vessels were determined on the second day of the treatment cycle prior to ovarian stimulation. Ovarian response was represented by the number of oocytes, serum oestradiol, and the duration and dosage of gonadotrophins. RESULTS: A total of 136 women were included in the analysis. Basal FSH concentration achieved the best predictive value in relation to the number of oocytes obtained, followed by AFC and BMI. AFC was the only predictive factor of serum oestradiol concentration on the day of HCG while BMI was predictive of the gonadotrophin dosage. CONCLUSION: Ovarian stromal blood flow indices measured by power Doppler ultrasound had no predictive value for the ovarian response.

Comparison of ovarian stromal blood flow between fertile women with normal ovaries and infertile women with polycystic ovary syndrome.

BACKGROUND: Conflicting information exists in the literature with respect to ovarian stromal blood flow in women with polycystic ovary syndrome (PCOS). We compared the ovarian stromal blood flow and serum vascular endothelial growth factor (VEGF) concentration between fertile women with normal ovaries and infertile women with PCOS. METHODS: In the second to fourth day of the menstrual period, they underwent transvaginal scanning with three-dimensional (3D) power Doppler to determine total antral follicle count (AFC), total ovarian volume, total ovarian vascularization index (VI), flow index (VFI) and vascularization flow index (VFI). Serum FSH, LH and VEGF concentrations were also checked. RESULTS: 107 fertile controls and 32 PCOS women were recruited. Fertile controls and PCOS women had similar total ovarian VI/FI/VFI after controlling for age of the woman, although PCOS women had significantly higher total AFC, total ovarian volume and serum LH concentration than fertile controls. Total ovarian VI/FI/VFI were significantly higher in normal weight (BMI < 25 kg/m2) PCOS women than their overweight (> or = 25 kg/m2) counterparts. CONCLUSIONS: Fertile controls and PCOS women had similar total ovarian 3D power Doppler flow indices. Normal weight PCOS women had significantly higher total ovarian 3D power Doppler flow indices than their overweight counterparts.

Antral follicle count and FSH concentration after clomiphene citrate challenge test in the prediction of ovarian response during IVF treatment.

BACKGROUND: We compared: (i) antral follicle count (AFC) in the early follicular phase, after the clomiphene citrate challenge test (CCCT) and before ovarian stimulation following pituitary down-regulation; and (ii) age of women, body mass index, basal and stimulated serum FSH concentrations and AFC in predicting the ovarian response of infertile women aged <40 years with basal FSH <10 IU/l on recruitment in their first IVF cycle. METHODS: Two months prior to the treatment cycle, AFC and basal FSH concentration were determined on day 2-3 of a spontaneous period and on day 10 after CCCT. All women received a standard stimulation regimen. Ovarian response was represented by the number of oocytes, serum estradiol, the duration and dosage of gonadotrophins. RESULTS: There was no significant difference between basal, stimulated and down-regulated AFC. AFC achieved the best predictive value in relation to the number of oocytes, followed by combined FSH concentration (sum of the two FSH concentrations) and age of women. Both basal AFC and combined FSH concentration were predictive factors of serum estradiol concentration, whereas stimulated FSH concentration was predictive of the total dosage of gonadotrophins. CONCLUSION: Combined FSH concentration after CCCT provides additional information in predicting ovarian response.

A randomized double-blind controlled study of the efficacy of laser-assisted hatching on implantation and pregnancy rates of frozen-thawed embryo transfer at the cleavage stage.

BACKGROUND: Assisted hatching (AH) in fresh embryo transfer (ET) cycles increases the implantation and pregnancy rates, especially in women with a poor prognosis, repeated implantation failures and in older women. Little information exists in the literature regarding the role of AH in frozen-thawed embryo transfer (FET) cycles. METHODS: Embryos were cryopreserved at the cleavage stage. On the day of FET, 160 patients were randomized according to a computer-generated randomization list in sealed envelopes into the AH group and the control group. The patients and the clinicians were blinded to the group assigned. In the AH group, the outer half of the zona pellucida over a quarter of the diameter of zona was removed using a 1480 nm non-contact laser. RESULTS: The two groups were comparable in terms of demographic characteristics, ovarian response of the stimulated cycle and quality of fresh and frozen-thawed embryos. No differences in implantation, pregnancy and multiple pregnancy rates were found between the two groups. There was a non-significant trend of a higher implantation rate in the AH group when the zona thickness was > or = 16 mm. CONCLUSION: Laser AH did not improve the implantation rate of FET cycles and should not be performed routinely in all frozen-thawed embryos at the cleavage stage.

Endometrial and subendometrial blood flow measured by three-dimensional power Doppler ultrasound in patients with small intramural uterine fibroids during IVF treatment.

BACKGROUND: The impact of intramural fibroids on the success of IVF treatment is controversial and the mechanisms leading to poor treatment outcomes remain unknown. We compared endometrial and subendometrial blood flow between women with and without intramural fibroids during IVF treatment. METHODS: Three-dimensional (3D) ultrasound examination with power Doppler was performed on the day of oocyte retrieval in 50 patients with intramural fibroids not distorting the uterine cavity and in 50 matched controls to measure endometrial thickness, uterine pulsatility index (PI)/resistance index (RI), endometrial volume and vascularization index (VI)/flow index (FI)/vascularization flow index (VFI) of endometrial and subendometrial regions. Smokers, patients with serum estradiol concentrations > or =20,000 pmol/l on the day of HCG and previous history of myomectomy were excluded. RESULTS: Endometrial thickness and pattern, averaged uterine PI and RI and endometrial and subendometrial VI/FI/VFI were similar between the fibroid group and the control group. There was no correlation between the total volume of fibroids and endometrial and subendometrial 3D power Doppler flow indices in the fibroid group. CONCLUSION: Endometrial and subendometrial 3D power Doppler flow indices were similar in patients with and without small intramural fibroids.

A prospective randomised comparison of sublingual and vaginal misoprostol in second trimester termination of pregnancy.

OBJECTIVE: To compare the efficacy, side effects and acceptability of sublingual and vaginal misoprostol for second trimester medical abortion. DESIGN: Prospective randomised controlled trial. SETTING: Tertiary referral unit and a teaching hospital. POPULATION: Two hundred and twenty-four women at 12 to 20 weeks of gestation. METHODS: The women were randomised to receive either sublingual or vaginal misoprostol 400 microg every 3 hours for a maximum of five doses. The course of misoprostol was repeated if the woman did not abort within 24 hours. MAIN OUTCOME MEASURES: The success rate at 48 hours, induction-to-abortion interval and the side effects. RESULTS: There was no significant difference in the success rate at 48 hours (sublingual: 91%; vaginal: 95%). However, the success rate at 24 hours was significantly higher in the vaginal group (85%) compared with the sublingual group (64%). There was no difference in the median induction-to-abortion interval (sublingual: 13.8 hours; vaginal: 12.0 hours). Significantly more women in the sublingual group preferred the route to which they were assigned when compared with the vaginal group. The incidence of fever was also less in the sublingual group. CONCLUSION: The use of vaginal misoprostol for second trimester medical abortion resulted in a higher success rate than sublingual misoprostol at 24 hours but the abortion rate was similar at 48 hours. Vaginal misoprostol should be the regimen of choice but sublingual misoprostol is also an effective alternative.

Comparison of endometrial and subendometrial blood flow measured by three-dimensional power Doppler ultrasound between stimulated and natural cycles in the same patients.

BACKGROUND: Low implantation rates in stimulated IVF cycles may be related to suboptimal endometrial perfusion. Endometrial and subendometrial blood flow was compared between stimulated and natural cycles in the same patients undergoing IVF. METHODS: Three-dimensional (3D) ultrasound examination with power Doppler was performed in stimulated and natural cycles of 67 consecutive patients to measure endometrial thickness, uterine artery pulsatility index/resistance index, endometrial volume, vascularization index (VI)/flow index (FI)/vascularization flow index (VFI) of endometrial and subendometrial regions. RESULTS: Endometrial and subendometrial blood flow was absent in four (6.0%) patients in the stimulated cycle and two (3.0%) patients in the natural cycle. Endometrial and subendometrial VI/FI/VFI were significantly lower in stimulated cycles than those in natural cycles. The median (95% CI) decreases in endometrial VI/FI/VFI were 35.8% (-2.5, 216.8), 5.0% (0.1, 12.3) and 48.4% (2.5, 315.3) respectively whereas the corresponding decreases in the subendometrial region were 66.6% (-0.2, 220.5), 4.3% (0.8, 16.2) and 76.3% (41.0, 303.4) respectively. CONCLUSION: Endometrial and subendometrial blood flow was significantly lower in the stimulated cycle than that in the natural cycle.