- Email: [email protected]
Doppler study of uterine hemodynamics in women with unexplained infertility
European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
Contents lists available at ScienceDirect
European Journal of Obstetrics & Gynecology and Reproductive Biology journal homepage: www.elsevier.com/locate/ejogrb
Doppler study of uterine hemodynamics in women with unexplained infertility Akmal El-Mazny *, Nermeen Abou-Salem, Hossam ElShenoufy Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Egypt
A R T I C L E I N F O
A B S T R A C T
Article history: Received 15 April 2013 Received in revised form 20 July 2013 Accepted 11 August 2013
Objective: To evaluate uterine artery blood flow using pulsed Doppler, and endometrial and subendometrial microvascularization using three-dimensional (3D) power Doppler, in women with unexplained infertility. Study design: In a prospective clinical trial at a university teaching hospital, 40 women with unexplained infertility were compared to 40 fertile parous controls. In the mid-luteal (peri-implantation) phase, the endometrial thickness and volume, uterine artery pulsatility index (PI) and resistance index (RI), endometrial and subendometrial 3D power Doppler vascularization index (VI), flow index (FI), and vascularization flow index (VFI), and serum estradiol and progesterone levels were measured in both groups. Results: The uterine artery PI (P = 0.003) and RI (P = 0.007) were significantly increased and the endometrial VI (P = 0.029), FI (P = 0.031), and VFI (P = 0.001) and subendometrial VI (P = 0.032), FI (P = 0.040), and VFI (P = 0.005) were significantly decreased in the unexplained infertility group. The endometrial thickness and volume and serum estradiol and progesterone levels, however, were not significantly different between the two groups. Conclusion: Peri-implantation endometrial perfusion is impaired in women with unexplained infertility: Doppler study of uterine hemodynamics should therefore be considered in infertility work-up. ß 2013 Elsevier Ireland Ltd. All rights reserved.
Keywords: 3D ultrasonography Doppler Endometrial perfusion.
1. Introduction Although the majority of infertile couples will be found to have an identifiable male or female factor, 15–30% will be categorized as having ‘‘unexplained infertility’’ [1]. The endometrium is considered to be a key determinant in successful implantation. Endometrial receptivity is regulated by many factors including endometrial perfusion [2]. Ultrasound examination of the endometrium is a commonly used non-invasive method of assessing endometrial receptivity during infertility treatment. Assessment of the endometrium, however, is usually limited to measurement of its thickness and description of its appearance, and these parameters may not be specific indicators of implantation [3]. Doppler ultrasound assessment of uterine blood flow appears to be more informative, but 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 (3D) power Doppler ultrasound [4].
* Corresponding author. Tel.: +20 1001454576; fax: +20 223643554. E-mail address: [email protected] (A. El-Mazny). 0301-2115/$ – see front matter ß 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejogrb.2013.08.026
The aim of this study was to evaluate uterine artery blood flow using pulsed Doppler, and endometrial and subendometrial microvascularization using 3D power Doppler, in women with unexplained infertility.
2. Materials and methods This prospective clinical trial was conducted at the Department of Obstetrics and Gynecology, Kasr El-Ainy Teaching Hospital, Faculty of Medicine, Cairo University, during the period from March 2011 to October 2012. The study protocol was approved by the Scientific Research Committee, and informed consent was obtained from all participants. The study group consisted of 40 women with primary or secondary unexplained infertility for more than 2 years. The diagnosis of unexplained infertility was based on: normal semen analysis by WHO criteria [5], documentation of ovulation by transvaginal ultrasonography and normal mid-luteal serum progesterone levels, and documentation of normal uterine cavity and bilateral tubal patency by hysterosalpingography and/or hysterolaparoscopy (if indicated). The control group consisted of 40 fertile parous women who had their last delivery during the 2 years before the study, and were requesting contraception.
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
85
Fig. 1. Virtual Organ Computer-Aided Analysis of the endometrium.
The inclusion criteria for both groups were: age from 25 to 35 years, normal regular menstrual cycle, body mass index (BMI) < 30 kg/m2, and normal pelvic examination and ultrasonography. The exclusion criteria were: history of pelvic surgery including cesarean section, history of pelvic inflammatory disease, clinical features suggestive of endometriosis, any pelvic pathology including uterine fibroids and ovarian cysts, any general disease or medication that could potentially affect pelvic blood flow, lactation, and smoking. In both groups, transvaginal ultrasound (Voluson 730; Kretz, Zipf, Austria) examinations were performed during the mid-luteal (peri-implantation) phase (day 20–22) of the cycle. At the same visit, blood samples were collected and immediately centrifuged; the sera were separated and stored at 70 8C until subsequent analysis. Serum estradiol and progesterone levels were measured using electrochemiluminescence immunoassay. Using ultrasound in the 2D mode, the endometrial thickness was measured as the thickest part in the sagittal plane (double layer). Then, color Doppler was activated and the flow velocity waveforms were obtained from the ascending main branch of the uterine artery on both sides of the internal os. Three similar
consecutive waveforms of good quality were analyzed. The right and left uterine artery pulsatility index (PI) and resistance index (RI) were calculated, and the averaged PI and RI were given. The ultrasound was then switched to the 3D mode with power Doppler. The setting conditions for this study were standardized using a frequency at 3–9 MHz, pulse repetition frequency at 0.6 kHz, gain at 4.0, and wall motion filter at low 1. The Virtual Organ Computer-Aided Analysis (VOCAL) imaging program was used to measure the endometrial volume and 3D power Doppler indices within the endometrium (Fig. 1) and the subendometrial region (Fig. 2) through the application of ‘‘shell-imaging’’ within 1 mm parallel to the originally defined myometrial–endometrial contour [6]. Vascularization index (VI) measures the ratio of the number of color voxels to the total number of voxels (%) and represents the presence of blood vessels (vascularity). Flow index (FI) measures the mean power Doppler signal intensity (0–100) and represents the average intensity of blood flow. Vascularization flow index (VFI) is calculated by multiplying VI and FI (0–100) and represents a combination of vascularity and flow intensity [7].
Fig. 2. Virtual Organ Computer-Aided Analysis of the subendometrial ‘‘shell’’.
86
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
Table 1 Comparison of clinical and hormonal characteristics between unexplained infertility group and control group. Variable
Infertility group
Control group
P value
Number of patients Age (years) Gravidity (n) Parity (n) Miscarriage (n) Menstrual cycle (d) BMI (kg/m2) Estradiol (pg/ml) Progesterone (ng/ml)
40 29.41 3.15 (28.40–30.42) 1.30 1.02 (0.97–1.63) 0.90 0.81 (0.64–1.16) 0.43 0.50 (0.27–0.59) 28.08 1.33 (27.65–28.51) 24.78 2.85 (23.87–25.69) 87.53 24.32 (79.75–95.31) 20.03 5.53 (18.26–21.80)
40 30.12 3.44 (29.02–31.22) 3.03 1.42 (2.58–3.48) 2.05 0.85 (1.78–2.32) 1.13 0.79 (0.88–1.38) 27.98 1.56 (27.48–28.48) 25.30 3.07 (24.32–26.28) 90.05 25.72 (81.82–98.28) 18.50 5.25 (16.82–20.18)
0.339 <0.001 <0.001 <0.001 0.758 0.430 0.653 0.209
Values are given as mean SD (95% CI).
Table 2 Comparison of endometrial measurements and Doppler indices between unexplained infertility group and control group. Variable
Infertility group
Control group
P value
Number of patients Endometrial thickness (mm) Uterine artery PI Uterine artery RI Endometrial volume (cm3) Endometrial VI (%) Endometrial FI (0–100) Endometrial VFI (0–100) Subendometrial VI (%) Subendometrial FI (0–100) Subendometrial VFI (0–100)
40 9.69 2.90 (8.77–10.62) 2.12 0.49 (1.96–2.28) 0.89 0.23 (0.82–0.96) 4.35 1.34 (3.92–4.78) 0.53 0.18 (0.47–0.59) 25.24 8.57 (22.50–27.98) 0.25 0.06 (0.23–0.27) 1.97 0.59 (1.78–2.16) 31.18 10.23 (27.91–34.45) 0.83 0.27 (0.74–0.92)
40 9.15 3.24 (8.12–10.19) 1.81 0.42 (1.68–1.94) 0.76 0.19 (0.70–0.82) 3.98 1.29 (3.57–4.39) 0.63 0.22 (0.56–0.70) 29.55 8.98 (26.68–32.43) 0.31 0.09 (0.28–0.34) 2.27 0.64 (2.07–2.47) 36.70 13.19 (32.48–40.92) 1.02 0.31 (0.92–1.12)
0.435 0.003 0.007 0.212 0.029 0.031 0.001 0.032 0.040 0.005
Values are given as mean SD (95% CI).
Data were expressed as mean SD (95% confidence interval (CI)). Student’s t test was used to compare the relevant variables between the two groups. A two-tailed P value < 0.05 was considered statistically significant. The Statistical Package for the Social Science (SPSS Inc., Chicago, IL, USA), version 16.0, was used for data analyses. 3. Results A total of 80 women met the recruitment criteria. The study group consisted of 40 women with primary (n = 21; 52.5%) or secondary (n = 19; 47.5%) unexplained infertility for more than two years (3.75 1.06). The control group consisted of 40 fertile parous women who had their last delivery during the two years (1.55 0.50) before the study. There were no significant differences in the age (P = 0.339), duration of menstrual cycle (P = 0.758), BMI (P = 0.430), or serum estradiol (P = 0.653) and progesterone (P = 0.209) levels between the two groups. The gravidity, parity, and miscarriage rate, however, were significantly lower (P < 0.001) in the unexplained infertility group (Table 1). The endometrial thickness (P = 0.435) and volume (P = 0.212) were not significantly different between the two groups. The uterine artery PI (P = 0.003) and RI (P = 0.007) were significantly increased, however, and the endometrial VI (P = 0.029), FI (P = 0.031), and VFI (P = 0.001) and subendometrial VI (P = 0.032), FI (P = 0.040), and VFI (P = 0.005) were significantly decreased in the unexplained infertility group (Table 2). 4. Comment It has been previously demonstrated that uterine blood flow changes periodically throughout the normal ovulatory menstrual cycle [8–10]. These studies almost universally reported a gradual yet continuous increase in blood flow velocity in association with a reduction in the resistance to flow through the menstrual cycle from the early follicular phase, maximal at the mid-luteal phase during which the endometrium has been transformed from
proliferative phase to secretory phase. At this specific time period the blood supply of the uterus is rich, and implantation is most likely to occur. Our results showed that the uterine artery PI and RI were significantly increased in the unexplained infertility group. The suggestion that women with unexplained infertility may have an impaired uterine blood flow was first raised by Goswamy et al. [11]. Using transabdominal pulsed wave Doppler, they described increased uterine artery impedance in women with no apparent cause for infertility. Subsequent studies also suggested that unexplained infertility may be associated with aberrant uterine artery blood flow and intermittently absent end-diastolic flow [12,13]. In addition, Doppler investigation of uterine artery blood flow may be very important in predicting the pregnant state in IVF cycles [9]; uterine artery PI and RI were found to be significantly lower in conception than in non-conception cycles [14,15]. Steer et al. [16,17] also found that uterine artery PI has a significant correlation with biochemical markers of uterine receptivity and accurately predicts the probability of pregnancy before the time of embryo transfer (ET). Other studies [18,19], however, reported that Doppler sonography of the uterine arteries was not a reliable predictor of subsequent IVF outcome. Our results also showed that the endometrial and subendometrial VI, FI, and VFI were significantly decreased in the unexplained infertility group. This is in agreement with Raine-Fenning et al. [20] who found that the endometrial and subendometrial 3D power Doppler vascularity indices were reduced in women with unexplained subfertility in comparison to the control group throughout the menstrual cycle, though these differences were significant only during the mid-late follicular phase and early luteal phase. Several studies have also reported that the detection of endometrial and subendometrial blood flow by transvaginal color and pulsed Doppler ultrasound [21,22] or 3D power Doppler ultrasound [23,24] may be useful in prediction of endometrial receptivity and the pregnancy rate of IVF cycles, which could be helpful data in a single-ET policy [24]. Other studies, however,
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
reported that neither pulsed Doppler sonography of spiral arteries [18,19] nor measurement of endometrial and subendometrial blood flows by 3D power Doppler ultrasound [25,26] allowed a reliable prediction of subsequent IVF outcome. Our findings suggest that abnormal endometrial perfusion may have a possible role in the pathogenesis of infertility. As there were no significant differences in endometrial thickness and volume or serum estradiol and progesterone levels between the two groups, we can hypothesize that the reduction in endometrial perfusion in the infertile group is more likely to reflect an aberrant end-organ effect of ovarian hormones on endometrial blood vessels. This may be due to suboptimal endometrial angiogenesis or dynamic vascular changes such as vasoconstriction or reduced vasodilatation [20]. Based on our findings, we can recommend that Doppler study of uterine hemodynamics should be considered in infertility work-up for better diagnostic capability and treatment modalities. Women with suboptimal uterine perfusion may be offered therapies improving uterine blood flow, such as low-dose aspirin [27,28], omega-3 [28], glyceryl trinitrate, angiogenic growth factors [29], or sildenafil citrate [30]. Embryo cryopreservation and subsequent endometrial preparation can be also considered in IVF patients. In conclusion, peri-implantation endometrial perfusion is impaired in women with unexplained infertility irrespective of the endometrial measurements and hormonal levels. This finding suggests that abnormal endometrial perfusion may have a possible role in the pathogenesis of infertility. Doppler study of uterine hemodynamics should therefore be considered in infertility workup, and women with suboptimal uterine perfusion may be offered therapy aimed at improving uterine blood flow. 5. Conflict of interest None. 6. Source of support None. References [1] Practice Committee of the American Society for Reproductive Medicine. Effectiveness and treatment for unexplained infertility. Fertil Steril 2006;86:S111–4. [2] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Factors affecting endometrial and subendometrial blood flow measured by three-dimensional power Doppler ultrasound during IVF treatment. Hum Reprod 2006;21:1062–9. [3] Friedler S, Schenker JG, Herman A, Lewin A. The role of ultrasonography in the evaluation of endometrial receptivity following assisted reproductive treatments: a critical review. Hum Reprod Update 1996;2:323–35. [4] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. The role of endometrial blood flow measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during in vitro fertilization treatment. Eur J Obstet Gynecol Reprod Biol 2007;135:8–16. [5] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th ed. Geneva, Switzerland: WHO; 2010. [6] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Endometrial and subendometrial blood flow measured during early luteal phase by three-dimensional power Doppler ultrasound in excessive ovarian responders. Hum Reprod 2004; 19:924–31.
87
[7] Pairleitner H, Steiner H, Hasenoehrl G, Staudach A. Three-dimensional power Doppler sonography: imaging and quantifying blood flow and vascularization. Ultrasound Obstet Gynecol 1999;14:139–43. [8] Goswamy RK, Steptoe PC. Doppler ultrasound studies of the uterine artery in spontaneous ovarian cycles. Hum Reprod 1988;3:721–6. [9] Battaglia C, Larocca E, Lanzani A, Valentini M, Genazzani AR. Doppler ultrasound studies of the uterine arteries in spontaneous and IVF stimulated ovarian cycles. Gynecol Endocrinol 1990;4:245–50. [10] Zaidi J. Blood flow changes in the ovarian and uterine arteries in women with normal and polycystic ovaries. Hum Fertil (Camb) 2000;3:194–8. [11] Goswamy RK, Williams G, Steptoe PC. Decreased uterine perfusion – a cause of infertility. Hum Reprod 1988;3:955–9. [12] Kurjak A, Kupesic-Urek S, Schulman H, Zalud I. Transvaginal color flow Doppler in the assessment of ovarian and uterine blood flow in infertile women. Fertil Steril 1991;56:870–3. [13] Steer CV, Tan SL, Mason BA, Campbell S. Midluteal-phase vaginal color Doppler assessment of uterine artery impedance in a subfertile population. Fertil Steril 1994;61:53–8. [14] Cacciatore B, Simberg N, Fusaro P, Tiitinen A. Transvaginal Doppler study of uterine artery blood flow in in vitro fertilization-embryo transfer cycles. Fertil Steril 1996;66:130–4. [15] Chien LW, Lee WS, Au HK, Tzeng CR. Assessment of changes in utero-ovarian arterial impedance during the peri-implantation period by Doppler sonography in women undergoing assisted reproduction. Ultrasound Obstet Gynecol 2004;23:496–500. [16] Steer CV, Campbell S, Tan SL, et al. The use of transvaginal color flow imaging after in vitro fertilization to identify optimum uterine conditions before embryo transfer. Fertil Steril 1992;57:372–6. [17] Steer CV, Tan SL, Dillon D, Mason BA, Campbell S. Vaginal color Doppler assessment of uterine artery impedance correlates with immunohistochemical markers of endometrial receptivity required for the implantation of an embryo. Fertil Steril 1995;63:101–8. [18] Schild RL, Knobloch C, Dorn C, Fimmers R, van der Ven H, Hansmann M. Endometrial receptivity in an in vitro fertilization program as assessed by spiral artery blood flow, endometrial thickness, endometrial volume, and uterine artery blood flow. Fertil Steril 2001;75:361–6. [19] Isaksson R, Tiitinen A, Reinikainen LM, Cacciatore B. Comparison of uterine and spiral artery blood flow in women with unexplained and tubal infertility. Ultrasound Obstet Gynecol 2003;21:174–80. [20] Raine-Fenning NJ, Campbell BK, Kendall NR, Clewes JS, Johnson IR. Endometrial and subendometrial perfusion are impaired in women with unexplained subfertility. Hum Reprod 2004;19:2605–14. [21] Zaidi J, Campbell S, Pittrof R, Tan SL. Endometrial thickness, morphology, vascular penetration and velocimetry in predicting implantation in an in vitro fertilization program. Ultrasound Obstet Gynecol 1995;6:191–8. [22] Chien LW, Au HK, Chen PL, Xiao J, Tzeng CR. Assessment of uterine receptivity by the endometrial–subendometrial blood flow distribution pattern in women undergoing in vitro fertilization-embryo transfer. Fertil Steril 2002;78:245–51. [23] Wu HM, Chiang CH, Huang HY, Chao AS, Wang HS, Soong YK. Detection of the subendometrial vascularization flow index by three-dimensional ultrasound may be useful for predicting the pregnancy rate for patients undergoing in vitro fertilization-embryo transfer. Fertil Steril 2003;79:507–11. [24] Merce´ LT, Barco MJ, Bau S, Troyano J. Are endometrial parameters by threedimensional ultrasound and power Doppler angiography related to in vitro fertilization/embryo transfer outcome? Fertil Steril 2008;89:111–7. [25] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. The role of endometrial and subendometrial blood flows measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during IVF treatment. Hum Reprod 2006;21:164–70. [26] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Changes in endometrial and subendometrial blood flow in IVF. Reprod Biomed Online 2009;18:269–75. [27] Rubinstein M, Marazzi A, Polak de Fried E. Low-dose aspirin treatment improves ovarian responsiveness, uterine and ovarian blood flow velocity, implantation, and pregnancy rates in patients undergoing in vitro fertilization: a prospective, randomized, double-blind placebo-controlled assay. Fertil Steril 1999;71:825–9. [28] Lazzarin N, Vaquero E, Exacoustos C, Bertonotti E, Romanini ME, Arduini D. Low-dose aspirin and omega-3 fatty acids improve uterine artery blood flow velocity in women with recurrent miscarriage due to impaired uterine perfusion. Fertil Steril 2009;92:296–300. [29] Azrin M. Angiogenesis protein and gene delivery. Br Med Bull 2001;59:211–25. [30] Sher G, Fisch JD. Effect of vaginal sildenafil on the outcome of in vitro fertilization (IVF) after multiple IVF failures attributed to poor endometrial development. Fertil Steril 2002;78:1073–6.
Contents lists available at ScienceDirect
European Journal of Obstetrics & Gynecology and Reproductive Biology journal homepage: www.elsevier.com/locate/ejogrb
Doppler study of uterine hemodynamics in women with unexplained infertility Akmal El-Mazny *, Nermeen Abou-Salem, Hossam ElShenoufy Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Egypt
A R T I C L E I N F O
A B S T R A C T
Article history: Received 15 April 2013 Received in revised form 20 July 2013 Accepted 11 August 2013
Objective: To evaluate uterine artery blood flow using pulsed Doppler, and endometrial and subendometrial microvascularization using three-dimensional (3D) power Doppler, in women with unexplained infertility. Study design: In a prospective clinical trial at a university teaching hospital, 40 women with unexplained infertility were compared to 40 fertile parous controls. In the mid-luteal (peri-implantation) phase, the endometrial thickness and volume, uterine artery pulsatility index (PI) and resistance index (RI), endometrial and subendometrial 3D power Doppler vascularization index (VI), flow index (FI), and vascularization flow index (VFI), and serum estradiol and progesterone levels were measured in both groups. Results: The uterine artery PI (P = 0.003) and RI (P = 0.007) were significantly increased and the endometrial VI (P = 0.029), FI (P = 0.031), and VFI (P = 0.001) and subendometrial VI (P = 0.032), FI (P = 0.040), and VFI (P = 0.005) were significantly decreased in the unexplained infertility group. The endometrial thickness and volume and serum estradiol and progesterone levels, however, were not significantly different between the two groups. Conclusion: Peri-implantation endometrial perfusion is impaired in women with unexplained infertility: Doppler study of uterine hemodynamics should therefore be considered in infertility work-up. ß 2013 Elsevier Ireland Ltd. All rights reserved.
Keywords: 3D ultrasonography Doppler Endometrial perfusion.
1. Introduction Although the majority of infertile couples will be found to have an identifiable male or female factor, 15–30% will be categorized as having ‘‘unexplained infertility’’ [1]. The endometrium is considered to be a key determinant in successful implantation. Endometrial receptivity is regulated by many factors including endometrial perfusion [2]. Ultrasound examination of the endometrium is a commonly used non-invasive method of assessing endometrial receptivity during infertility treatment. Assessment of the endometrium, however, is usually limited to measurement of its thickness and description of its appearance, and these parameters may not be specific indicators of implantation [3]. Doppler ultrasound assessment of uterine blood flow appears to be more informative, but 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 (3D) power Doppler ultrasound [4].
* Corresponding author. Tel.: +20 1001454576; fax: +20 223643554. E-mail address: [email protected] (A. El-Mazny). 0301-2115/$ – see front matter ß 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejogrb.2013.08.026
The aim of this study was to evaluate uterine artery blood flow using pulsed Doppler, and endometrial and subendometrial microvascularization using 3D power Doppler, in women with unexplained infertility.
2. Materials and methods This prospective clinical trial was conducted at the Department of Obstetrics and Gynecology, Kasr El-Ainy Teaching Hospital, Faculty of Medicine, Cairo University, during the period from March 2011 to October 2012. The study protocol was approved by the Scientific Research Committee, and informed consent was obtained from all participants. The study group consisted of 40 women with primary or secondary unexplained infertility for more than 2 years. The diagnosis of unexplained infertility was based on: normal semen analysis by WHO criteria [5], documentation of ovulation by transvaginal ultrasonography and normal mid-luteal serum progesterone levels, and documentation of normal uterine cavity and bilateral tubal patency by hysterosalpingography and/or hysterolaparoscopy (if indicated). The control group consisted of 40 fertile parous women who had their last delivery during the 2 years before the study, and were requesting contraception.
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
85
Fig. 1. Virtual Organ Computer-Aided Analysis of the endometrium.
The inclusion criteria for both groups were: age from 25 to 35 years, normal regular menstrual cycle, body mass index (BMI) < 30 kg/m2, and normal pelvic examination and ultrasonography. The exclusion criteria were: history of pelvic surgery including cesarean section, history of pelvic inflammatory disease, clinical features suggestive of endometriosis, any pelvic pathology including uterine fibroids and ovarian cysts, any general disease or medication that could potentially affect pelvic blood flow, lactation, and smoking. In both groups, transvaginal ultrasound (Voluson 730; Kretz, Zipf, Austria) examinations were performed during the mid-luteal (peri-implantation) phase (day 20–22) of the cycle. At the same visit, blood samples were collected and immediately centrifuged; the sera were separated and stored at 70 8C until subsequent analysis. Serum estradiol and progesterone levels were measured using electrochemiluminescence immunoassay. Using ultrasound in the 2D mode, the endometrial thickness was measured as the thickest part in the sagittal plane (double layer). Then, color Doppler was activated and the flow velocity waveforms were obtained from the ascending main branch of the uterine artery on both sides of the internal os. Three similar
consecutive waveforms of good quality were analyzed. The right and left uterine artery pulsatility index (PI) and resistance index (RI) were calculated, and the averaged PI and RI were given. The ultrasound was then switched to the 3D mode with power Doppler. The setting conditions for this study were standardized using a frequency at 3–9 MHz, pulse repetition frequency at 0.6 kHz, gain at 4.0, and wall motion filter at low 1. The Virtual Organ Computer-Aided Analysis (VOCAL) imaging program was used to measure the endometrial volume and 3D power Doppler indices within the endometrium (Fig. 1) and the subendometrial region (Fig. 2) through the application of ‘‘shell-imaging’’ within 1 mm parallel to the originally defined myometrial–endometrial contour [6]. Vascularization index (VI) measures the ratio of the number of color voxels to the total number of voxels (%) and represents the presence of blood vessels (vascularity). Flow index (FI) measures the mean power Doppler signal intensity (0–100) and represents the average intensity of blood flow. Vascularization flow index (VFI) is calculated by multiplying VI and FI (0–100) and represents a combination of vascularity and flow intensity [7].
Fig. 2. Virtual Organ Computer-Aided Analysis of the subendometrial ‘‘shell’’.
86
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
Table 1 Comparison of clinical and hormonal characteristics between unexplained infertility group and control group. Variable
Infertility group
Control group
P value
Number of patients Age (years) Gravidity (n) Parity (n) Miscarriage (n) Menstrual cycle (d) BMI (kg/m2) Estradiol (pg/ml) Progesterone (ng/ml)
40 29.41 3.15 (28.40–30.42) 1.30 1.02 (0.97–1.63) 0.90 0.81 (0.64–1.16) 0.43 0.50 (0.27–0.59) 28.08 1.33 (27.65–28.51) 24.78 2.85 (23.87–25.69) 87.53 24.32 (79.75–95.31) 20.03 5.53 (18.26–21.80)
40 30.12 3.44 (29.02–31.22) 3.03 1.42 (2.58–3.48) 2.05 0.85 (1.78–2.32) 1.13 0.79 (0.88–1.38) 27.98 1.56 (27.48–28.48) 25.30 3.07 (24.32–26.28) 90.05 25.72 (81.82–98.28) 18.50 5.25 (16.82–20.18)
0.339 <0.001 <0.001 <0.001 0.758 0.430 0.653 0.209
Values are given as mean SD (95% CI).
Table 2 Comparison of endometrial measurements and Doppler indices between unexplained infertility group and control group. Variable
Infertility group
Control group
P value
Number of patients Endometrial thickness (mm) Uterine artery PI Uterine artery RI Endometrial volume (cm3) Endometrial VI (%) Endometrial FI (0–100) Endometrial VFI (0–100) Subendometrial VI (%) Subendometrial FI (0–100) Subendometrial VFI (0–100)
40 9.69 2.90 (8.77–10.62) 2.12 0.49 (1.96–2.28) 0.89 0.23 (0.82–0.96) 4.35 1.34 (3.92–4.78) 0.53 0.18 (0.47–0.59) 25.24 8.57 (22.50–27.98) 0.25 0.06 (0.23–0.27) 1.97 0.59 (1.78–2.16) 31.18 10.23 (27.91–34.45) 0.83 0.27 (0.74–0.92)
40 9.15 3.24 (8.12–10.19) 1.81 0.42 (1.68–1.94) 0.76 0.19 (0.70–0.82) 3.98 1.29 (3.57–4.39) 0.63 0.22 (0.56–0.70) 29.55 8.98 (26.68–32.43) 0.31 0.09 (0.28–0.34) 2.27 0.64 (2.07–2.47) 36.70 13.19 (32.48–40.92) 1.02 0.31 (0.92–1.12)
0.435 0.003 0.007 0.212 0.029 0.031 0.001 0.032 0.040 0.005
Values are given as mean SD (95% CI).
Data were expressed as mean SD (95% confidence interval (CI)). Student’s t test was used to compare the relevant variables between the two groups. A two-tailed P value < 0.05 was considered statistically significant. The Statistical Package for the Social Science (SPSS Inc., Chicago, IL, USA), version 16.0, was used for data analyses. 3. Results A total of 80 women met the recruitment criteria. The study group consisted of 40 women with primary (n = 21; 52.5%) or secondary (n = 19; 47.5%) unexplained infertility for more than two years (3.75 1.06). The control group consisted of 40 fertile parous women who had their last delivery during the two years (1.55 0.50) before the study. There were no significant differences in the age (P = 0.339), duration of menstrual cycle (P = 0.758), BMI (P = 0.430), or serum estradiol (P = 0.653) and progesterone (P = 0.209) levels between the two groups. The gravidity, parity, and miscarriage rate, however, were significantly lower (P < 0.001) in the unexplained infertility group (Table 1). The endometrial thickness (P = 0.435) and volume (P = 0.212) were not significantly different between the two groups. The uterine artery PI (P = 0.003) and RI (P = 0.007) were significantly increased, however, and the endometrial VI (P = 0.029), FI (P = 0.031), and VFI (P = 0.001) and subendometrial VI (P = 0.032), FI (P = 0.040), and VFI (P = 0.005) were significantly decreased in the unexplained infertility group (Table 2). 4. Comment It has been previously demonstrated that uterine blood flow changes periodically throughout the normal ovulatory menstrual cycle [8–10]. These studies almost universally reported a gradual yet continuous increase in blood flow velocity in association with a reduction in the resistance to flow through the menstrual cycle from the early follicular phase, maximal at the mid-luteal phase during which the endometrium has been transformed from
proliferative phase to secretory phase. At this specific time period the blood supply of the uterus is rich, and implantation is most likely to occur. Our results showed that the uterine artery PI and RI were significantly increased in the unexplained infertility group. The suggestion that women with unexplained infertility may have an impaired uterine blood flow was first raised by Goswamy et al. [11]. Using transabdominal pulsed wave Doppler, they described increased uterine artery impedance in women with no apparent cause for infertility. Subsequent studies also suggested that unexplained infertility may be associated with aberrant uterine artery blood flow and intermittently absent end-diastolic flow [12,13]. In addition, Doppler investigation of uterine artery blood flow may be very important in predicting the pregnant state in IVF cycles [9]; uterine artery PI and RI were found to be significantly lower in conception than in non-conception cycles [14,15]. Steer et al. [16,17] also found that uterine artery PI has a significant correlation with biochemical markers of uterine receptivity and accurately predicts the probability of pregnancy before the time of embryo transfer (ET). Other studies [18,19], however, reported that Doppler sonography of the uterine arteries was not a reliable predictor of subsequent IVF outcome. Our results also showed that the endometrial and subendometrial VI, FI, and VFI were significantly decreased in the unexplained infertility group. This is in agreement with Raine-Fenning et al. [20] who found that the endometrial and subendometrial 3D power Doppler vascularity indices were reduced in women with unexplained subfertility in comparison to the control group throughout the menstrual cycle, though these differences were significant only during the mid-late follicular phase and early luteal phase. Several studies have also reported that the detection of endometrial and subendometrial blood flow by transvaginal color and pulsed Doppler ultrasound [21,22] or 3D power Doppler ultrasound [23,24] may be useful in prediction of endometrial receptivity and the pregnancy rate of IVF cycles, which could be helpful data in a single-ET policy [24]. Other studies, however,
A. El-Mazny et al. / European Journal of Obstetrics & Gynecology and Reproductive Biology 171 (2013) 84–87
reported that neither pulsed Doppler sonography of spiral arteries [18,19] nor measurement of endometrial and subendometrial blood flows by 3D power Doppler ultrasound [25,26] allowed a reliable prediction of subsequent IVF outcome. Our findings suggest that abnormal endometrial perfusion may have a possible role in the pathogenesis of infertility. As there were no significant differences in endometrial thickness and volume or serum estradiol and progesterone levels between the two groups, we can hypothesize that the reduction in endometrial perfusion in the infertile group is more likely to reflect an aberrant end-organ effect of ovarian hormones on endometrial blood vessels. This may be due to suboptimal endometrial angiogenesis or dynamic vascular changes such as vasoconstriction or reduced vasodilatation [20]. Based on our findings, we can recommend that Doppler study of uterine hemodynamics should be considered in infertility work-up for better diagnostic capability and treatment modalities. Women with suboptimal uterine perfusion may be offered therapies improving uterine blood flow, such as low-dose aspirin [27,28], omega-3 [28], glyceryl trinitrate, angiogenic growth factors [29], or sildenafil citrate [30]. Embryo cryopreservation and subsequent endometrial preparation can be also considered in IVF patients. In conclusion, peri-implantation endometrial perfusion is impaired in women with unexplained infertility irrespective of the endometrial measurements and hormonal levels. This finding suggests that abnormal endometrial perfusion may have a possible role in the pathogenesis of infertility. Doppler study of uterine hemodynamics should therefore be considered in infertility workup, and women with suboptimal uterine perfusion may be offered therapy aimed at improving uterine blood flow. 5. Conflict of interest None. 6. Source of support None. References [1] Practice Committee of the American Society for Reproductive Medicine. Effectiveness and treatment for unexplained infertility. Fertil Steril 2006;86:S111–4. [2] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Factors affecting endometrial and subendometrial blood flow measured by three-dimensional power Doppler ultrasound during IVF treatment. Hum Reprod 2006;21:1062–9. [3] Friedler S, Schenker JG, Herman A, Lewin A. The role of ultrasonography in the evaluation of endometrial receptivity following assisted reproductive treatments: a critical review. Hum Reprod Update 1996;2:323–35. [4] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. The role of endometrial blood flow measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during in vitro fertilization treatment. Eur J Obstet Gynecol Reprod Biol 2007;135:8–16. [5] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th ed. Geneva, Switzerland: WHO; 2010. [6] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Endometrial and subendometrial blood flow measured during early luteal phase by three-dimensional power Doppler ultrasound in excessive ovarian responders. Hum Reprod 2004; 19:924–31.
87
[7] Pairleitner H, Steiner H, Hasenoehrl G, Staudach A. Three-dimensional power Doppler sonography: imaging and quantifying blood flow and vascularization. Ultrasound Obstet Gynecol 1999;14:139–43. [8] Goswamy RK, Steptoe PC. Doppler ultrasound studies of the uterine artery in spontaneous ovarian cycles. Hum Reprod 1988;3:721–6. [9] Battaglia C, Larocca E, Lanzani A, Valentini M, Genazzani AR. Doppler ultrasound studies of the uterine arteries in spontaneous and IVF stimulated ovarian cycles. Gynecol Endocrinol 1990;4:245–50. [10] Zaidi J. Blood flow changes in the ovarian and uterine arteries in women with normal and polycystic ovaries. Hum Fertil (Camb) 2000;3:194–8. [11] Goswamy RK, Williams G, Steptoe PC. Decreased uterine perfusion – a cause of infertility. Hum Reprod 1988;3:955–9. [12] Kurjak A, Kupesic-Urek S, Schulman H, Zalud I. Transvaginal color flow Doppler in the assessment of ovarian and uterine blood flow in infertile women. Fertil Steril 1991;56:870–3. [13] Steer CV, Tan SL, Mason BA, Campbell S. Midluteal-phase vaginal color Doppler assessment of uterine artery impedance in a subfertile population. Fertil Steril 1994;61:53–8. [14] Cacciatore B, Simberg N, Fusaro P, Tiitinen A. Transvaginal Doppler study of uterine artery blood flow in in vitro fertilization-embryo transfer cycles. Fertil Steril 1996;66:130–4. [15] Chien LW, Lee WS, Au HK, Tzeng CR. Assessment of changes in utero-ovarian arterial impedance during the peri-implantation period by Doppler sonography in women undergoing assisted reproduction. Ultrasound Obstet Gynecol 2004;23:496–500. [16] Steer CV, Campbell S, Tan SL, et al. The use of transvaginal color flow imaging after in vitro fertilization to identify optimum uterine conditions before embryo transfer. Fertil Steril 1992;57:372–6. [17] Steer CV, Tan SL, Dillon D, Mason BA, Campbell S. Vaginal color Doppler assessment of uterine artery impedance correlates with immunohistochemical markers of endometrial receptivity required for the implantation of an embryo. Fertil Steril 1995;63:101–8. [18] Schild RL, Knobloch C, Dorn C, Fimmers R, van der Ven H, Hansmann M. Endometrial receptivity in an in vitro fertilization program as assessed by spiral artery blood flow, endometrial thickness, endometrial volume, and uterine artery blood flow. Fertil Steril 2001;75:361–6. [19] Isaksson R, Tiitinen A, Reinikainen LM, Cacciatore B. Comparison of uterine and spiral artery blood flow in women with unexplained and tubal infertility. Ultrasound Obstet Gynecol 2003;21:174–80. [20] Raine-Fenning NJ, Campbell BK, Kendall NR, Clewes JS, Johnson IR. Endometrial and subendometrial perfusion are impaired in women with unexplained subfertility. Hum Reprod 2004;19:2605–14. [21] Zaidi J, Campbell S, Pittrof R, Tan SL. Endometrial thickness, morphology, vascular penetration and velocimetry in predicting implantation in an in vitro fertilization program. Ultrasound Obstet Gynecol 1995;6:191–8. [22] Chien LW, Au HK, Chen PL, Xiao J, Tzeng CR. Assessment of uterine receptivity by the endometrial–subendometrial blood flow distribution pattern in women undergoing in vitro fertilization-embryo transfer. Fertil Steril 2002;78:245–51. [23] Wu HM, Chiang CH, Huang HY, Chao AS, Wang HS, Soong YK. Detection of the subendometrial vascularization flow index by three-dimensional ultrasound may be useful for predicting the pregnancy rate for patients undergoing in vitro fertilization-embryo transfer. Fertil Steril 2003;79:507–11. [24] Merce´ LT, Barco MJ, Bau S, Troyano J. Are endometrial parameters by threedimensional ultrasound and power Doppler angiography related to in vitro fertilization/embryo transfer outcome? Fertil Steril 2008;89:111–7. [25] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. The role of endometrial and subendometrial blood flows measured by three-dimensional power Doppler ultrasound in the prediction of pregnancy during IVF treatment. Hum Reprod 2006;21:164–70. [26] Ng EH, Chan CC, Tang OS, Yeung WS, Ho PC. Changes in endometrial and subendometrial blood flow in IVF. Reprod Biomed Online 2009;18:269–75. [27] Rubinstein M, Marazzi A, Polak de Fried E. Low-dose aspirin treatment improves ovarian responsiveness, uterine and ovarian blood flow velocity, implantation, and pregnancy rates in patients undergoing in vitro fertilization: a prospective, randomized, double-blind placebo-controlled assay. Fertil Steril 1999;71:825–9. [28] Lazzarin N, Vaquero E, Exacoustos C, Bertonotti E, Romanini ME, Arduini D. Low-dose aspirin and omega-3 fatty acids improve uterine artery blood flow velocity in women with recurrent miscarriage due to impaired uterine perfusion. Fertil Steril 2009;92:296–300. [29] Azrin M. Angiogenesis protein and gene delivery. Br Med Bull 2001;59:211–25. [30] Sher G, Fisch JD. Effect of vaginal sildenafil on the outcome of in vitro fertilization (IVF) after multiple IVF failures attributed to poor endometrial development. Fertil Steril 2002;78:1073–6.