Changes in uterine and ovarian arterial impedance during the periovulatory period in conception and nonconception cycles

The definition of unexplained infertility: A systematic review

BACKGROUND

There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice.

OBJECTIVES

This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis.

SEARCH STRATEGY

CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language.

DATA COLLECTION AND ANALYSIS

Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range.

MAIN RESULTS

Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies.

CONCLUSIONS

This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care.

Role of low-molecular-weight heparin in altering uterine artery blood flow in recurrent spontaneous abortion: a prospective study

OBJECTIVE

This study aimed to determine the role of uterine artery blood flow (UABF) in recurrent spontaneous abortion (RSA) and to determine a viable option to promote the outcome of pregnancy.

METHODS

A total of 421 women were prospectively recruited for this research. UABF indices, including the systolic/diastolic ratio, pulsatility index and resistance index, during the midluteal phase were compared between patients with RSA and women without RSA (controls). After low-molecular-weight heparin (LMWH) was administered to patients with RSA, indices at 7, 10, and 12 weeks of gestation were compared between the two groups.

RESULTS

UABF indices during the midluteal phase were significantly higher in the RSA group than in the control group. After LMWH was administered to the RSA group, UABF indices in the first trimester were similar to those in the control group. The rate of spontaneous miscarriage was also similar between the groups after LMWH treatment.

CONCLUSIONS

Our study shows that sufficient uterine perfusion is crucial for a successful pregnancy. LMWH reduces the rate of spontaneous miscarriage in patients with RSA to a similar rate in women without RSA. LMWH might play a role in decreasing UABF resistance and increasing uterine perfusion.

Does bilateral uterine artery ligation have negative effects on ovarian reserve markers and ovarian artery blood flow in women with postpartum hemorrhage?

OBJECTIVE

Bilateral uterine artery ligation (UAL) is a fertility-preserving procedure used in women experiencing postpartum hemorrhage (PPH). However, the long-term effects of this procedure on ovarian function remain unclear. The aim of this study was to investigate whether bilateral UAL compromised ovarian reserve and ovarian blood supply.

Methods

This prospective study included 49 women aged between 21 and 36 years who had undergone a cesarean section for obstetric indications. Of these, 25 underwent uterine bilateral UAL to control intractable atonic PPH. The control group consisted of 24 women who had not undergone bilateral UAL. Standard clinical parameters, the results of color Doppler screening, and ovarian reserve markers were assessed in all participants at 6 months after surgery. The clinical parameters included age, parity, cycle history, body mass index, and previous medication and/or surgery. Color Doppler screening findings included the pulsatility index (PI) and resistance index (RI) for both the uterine and ovarian arteries. The ovarian reserve markers included day 3 follicle-stimulating hormone (FSH) levels, antral follicle count, and anti-Müllerian hormone (AMH) levels.

RESULTS

There were no significant differences in the ovarian reserve markers of day 3 FSH levels, antral follicle count, and AMH levels between the study and control groups (p>0.05 for all). In addition, no significant differences were observed in the PI and RI indices of the uterine and ovarian arteries (p>0.05 for all).

CONCLUSION

In this study, we showed that bilateral UAL had no negative effects on ovarian reserve or ovarian blood supply, so this treatment should be used as a fertility preservation technique to avoid hysterectomy in patients experiencing PPH.

A comparative analysis of arterial blood flow in unexplained infertility, tubal infertility and fertile groups

We aimed to compare ovarian (O), uterine (U) and spiral (S) artery (A) resistance of patients diagnosed as fertile, unexplained infertility (UI) and tubal factor infertility (TFI) in the peri-implantation period and independent from the impact of the treatment. UI (n = 70), TFI (n = 75) and fertile (n = 72) patients' ovarian, uterine and spiral artery pulsatility index (PI), resistance index (RI) and the endometrial thickness, serum estradiol and progesterone levels were compared. The specificity and sensitivity values were calculated according to determined cutoff values. Both TFI and control groups' UA PI values were significantly lower than the UI group's PI values. The highest UA RI values were found in UI group and the lowest values were in the control group. UI and TFI groups' OA PI/RI values were significantly higher than the control group. Both the control and TFI groups' SA PI/RI values were significantly lower than UI group's PI/RI values. UI patients' uterine and spiral arteries PI values >1.86 and >0.85, RI values >0.80 and >0.53 can be used as a valuable test showing reduced uterine perfusion. Ovarian artery PI values  >0.96 and RI values  >0.58 can be used as tests showing decreased ovarian perfusion in patients with TFI. In these patients, embryo cryopreservation can be considered.

A randomized controlled trial evaluating the effect of ethinyl estradiol during clomiphene citrate cycles among women with polycystic ovary syndrome

OBJECTIVE

To investigate the effects of low-dose ethinyl estradiol (EE) on the clinical pregnancy rate among women with polycystic ovary syndrome (PCOS) undergoing ovulation induction with clomiphene citrate (CC).

METHODS

Between March 12, 2011, and February 10, 2013, a randomized, double-blind, placebo-controlled trial was conducted at the Royan Institute Research Center, Tehran, Iran, among women with PCOS who were aged 25-30 years, were undergoing their first intrauterine insemination cycle, and had a history (≥2 years) of infertility, oligomenorrhea, or amenorrhea. Participants were randomly allocated to receive EE (0.05 mg daily for 5 days) or placebo, co-administered with CC cycles (100 mg daily for 5 days). The primary outcome was clinical pregnancy rate. Analyses were per protocol: patients who discontinued the intervention were excluded.

RESULTS

Analyses included 45 women who received CC and EE, and 50 women who received CC and placebo. The number of women who achieved a clinical pregnancy was higher among participants who received CC and EE (13 [29%]) than among those in the control group (5 [10%]; P =0 .02). No adverse effects of EE were reported.

CONCLUSION

The combination of CC and EE seems to increase the clinical pregnancy rate among women with PCOS undergoing intrauterine insemination. ClinicalTrials.gov:NCT01219101.

Is it possible to predict a fertile cycle? Uteroovarian blood flow parameters in conception versus nonconception cycles

OBJECTIVE

To compare uterine and ovarian blood flow, measured by Doppler ultrasound, in the follicular phase of the menstrual cycle, in women who conceived to women who did not conceive during that cycle.

DESIGN

A prospective study of 192 women looking at markers of ovarian reserve between August 2000 and September 2002.

SETTING

A fertility clinic.

PATIENT(S)

A cross-section of women attending for fertility advice and treatment.

INTERVENTION(S)

Each woman was monitored during a natural cycle and then during a clomiphene challenge cycle (100 mg clomiphene given for 5 days from days 3-7 of the cycle). Doppler ultrasound scans were performed on days 3 and 12 of the natural cycle and day 11 of the clomiphene challenge cycle.

MAIN OUTCOME MEASURE(S)

Cycles in which women conceived were compared with those in which women did not conceive to see whether there were differences in uteroovarian blood flow parameters as measured by Doppler ultrasound scan in the follicular phase of the cycle.

RESULT(S)

In the 15 natural conception cycles there was an increased uterine artery peak systolic velocity at day 12 compared with 131 natural nonconception cycles (in which there was an opportunity to conceive). There were no differences in any uteroovarian blood flow parameters at day 3, and no differences in ovarian blood flow parameters (dominant follicle blood flow, dominant follicle pulsatility index), endometrial thickness or pulsatility at day 12. No differences were seen in any blood flow parameters in 10 clomiphene conception cycles compared with 116 clomiphene nonconception cycles.

CONCLUSION(S)

In the late follicular phase of natural conception cycles there is an increased uterine artery peak systolic velocity compared with nonconception cycles. This was not seen in clomiphene cycles in which conception occurred. There is very little in the literature comparing natural or clomiphene conception with nonconception cycles.

Ultrasonographic characterization of the uterine artery in the nonestrus bitch

The canine species is often used as an experimental animal model in medicine. Doppler ultrasound of uterine arteries has important clinical implications in obstetrics and gynecology in women and animal species. To our knowledge, the ultrasonographic features of uterine arteries in the bitch have not been reported. Thus, an ultrasonographic technique to locate the uterine arteries in the bitch is described in this study. A total of 11 nonspayed nonestrus bitches underwent abdominal ultrasound examination. Pulsed-wave, color and power Doppler settings were used to detect the location and characterize the flow of the uterine arteries. Mean values for systolic peak velocity, diastolic peak velocity, diastolic reversal flow and resistive index were calculated. Uterine arteries had a high pulsatility flow in all cases. Future work is needed to fully assess the clinical importance of the uterine artery flow in the bitch, as well as to study possible waveform changes at different estrus phases and throughout gestation.

A reduction in intraovarian arterial blood flow resistance after ovulation is necessary to achieve pregnancy in natural cycle

PURPOSE

Color Doppler imaging permits the accurate localization of vessels and high-frequency pulsed Doppler ultrasonography has improved the resolution of flow velocity waveforms. In this study, intraovarian arterial blood flow before and after follicle rupture in the natural cycle was examined using transvaginal color flow Doppler imaging and changes in intraovarian arterial resistance in relation to the outcome of infertility treatment was analyzed.

METHODS

In a prospective study, 227 spontaneous cycles in 118 infertile patients who were undergoing infertility treatment at the division of Reproductive Medicine in our center were recruited in this study. The impedance to flow in intraovarian vessels was measured by means of transvaginal color flow Doppler imaging during the periovulatory period in the natural cycle of all patients. The pulsatility index (PI) of intraovarian arterial blood flow and pregnancy rate was evaluated.

RESULTS

On the basis of PI values before and after follicular rupture, 227 cycles were classified into severely decreased (113 cycles) and not-severely decreased groups (114 cycles). The pregnancy rate per cycle in the severely decreased group was 18.6% (21/113), significantly higher than that in the not-severely decreased group (7/114; 6.1%, p = 0.004). The miscarriage rate was similar in the two groups.

CONCLUSIONS

A reduction in intraovarian blood vessel resistance is necessary to achieve pregnancy in a natural cycle.

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.

Assessment of endometrial perfusion with Doppler ultrasound in spontaneous and stimulated menstrual cycles

OBJECTIVE

Endometrial perfusions were measured by Doppler ultrasound to evaluate the influence of spontaneous menstrual cycles and to study the effect of clomiphene citrate.

METHODS

Flow waveforms in right and left uterine arteries were obtained by using transvaginal color Doppler ultrasonography in infertile women with 60 spontaneous menstrual cycles and 37 clomiphene citrate stimulated cycles from the follicular to the luteal phase.

RESULTS

In the spontaneous menstrual cycles, the uterine arterial blood flow increased significantly from the follicular phase to the day of ovulation and then increased markedly to about 200 approximately 230% of the follicular phase after the 6th day of ovulation. In the clomiphene citrate stimulated cycles, the uterine arterial blood flow did not change during the periovulatory period and then increased significantly to about 180 approximately 220% of the follicular phase after the 6th day of ovulation.

CONCLUSIONS

In the present study, the clomiphene citrate stimulated cycles showed lower endometrial perfusion during the periovulatory period compared with those in the spontaneous menstrual cycles. The results suggest that the assessment of endometrial perfusion with Doppler ultrasound can be used to reveal unexplained infertility problems in induced ovarian cycles.