Characteristics of uterine peristalsis in spontaneous and induced cycles

Does adjuvant letrozole reduce uterine peristalsis prior to fresh embryo transfer?

STUDY QUESTION

Does adjuvant letrozole in ovarian stimulation for in vitro fertilization (IVF) decrease the uterine peristalsis frequency (UPF) prior to fresh embryo transfer (ET)?

SUMMARY ANSWER

Adjuvant letrozole in ovarian stimulation for IVF does not reduce the UPF significantly prior to fresh ET.

WHAT IS KNOWN ALREADY

Throughout the cycle uterine peristalsis aids spermatozoa transport to the fallopian tube and may affect implantation. At fresh ET, UPF is negatively correlated with implantation and clinical pregnancy rates and is believed to be modulated by estradiol and progesterone. High levels of estradiol, from multiple follicular development, in ovarian stimulation have been reported to increase UPF, whereas progesterone is considered to be an utero-relaxant. The influence of androgens is unclear. Co-treatment with letrozole during gonadotropin ovarian stimulation limits the supra-physiological estradiol rise and may therefore reduce UPF prior to fresh ET.

STUDY DESIGN, SIZE, DURATION

This study was carried out on subjects participating in a single centre double blinded randomised controlled trial (RCT) of the impact of letrozole on follicle development and endocrine profiles, and investigated the impact of adjuvant letrozole in ovarian stimulation for IVF on UPF prior to fresh ET and the correlations of UPF with endocrine markers. Between 2016 and 2017, 39 women expected to be normal responders were randomised to co-treatment with letrozole or placebo. Of these, 33 women completed this element of the study. The study was carried out according to the Helsinki Declaration and the ICH-Good-Clinical-Practice.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible women were randomised 1:1 to adjuvant treatment with letrozole 5 mg/day or placebo in an antagonist protocol using a fixed dose of recombinant (r) FSH 150 IU/day. Final maturation was triggered with hCG 6,500 IU and luteal support with vaginal progesterone was administered from the day following oocyte aspiration. Less than one hour prior to fresh ET, six-minute duration transvaginal ultrasound recordings of the uterus in sagittal section were performed and blood samples were drawn.

MAIN RESULTS AND THE ROLE OF CHANGE

A total of 33 women completed the study (letrozole n = 17; placebo n = 16). Age, BMI and ovarian reserve markers were similar between the groups. On day of ET, serum estradiol levels were significantly suppressed in the letrozole group to a mean of 867 ± 827 pmol/L compared to 3,110 ± 1,528 pmol/L in the placebo group (P < 0.001). Mean UPF prior to fresh ET did not differ between the intervention and placebo group (3.3 ± 0.36 versus 3.5 ± 0.51 per minute respectively, P = 0.108). UPF was assessed and agreed by two observers who were blinded to adjuvant treatment. Two patients were excluded due to poor quality of the ultrasound recordings. Supra-physiological serum estradiol in the placebo group were negatively correlated with UPF (P = 0.014; R = -0.62), but the more physiological serum estradiol levels in the letrozole group showed no correlation with UPF (P = 0.567; R = 0.15). Serum progesterone levels were similar in both groups and did not show any significant correlation with UPF. Testosterone levels were significantly higher in the letrozole group (P = 0.005) and showed a non-significant trend that negatively correlated with UPF in the placebo group (P-value=0.071, R= -0.48).

LIMITATIONS, REASONS FOR CAUTION

Limitations of the study included the limited sample size and the lack of a power calculation specifically determined for this endpoint.

WIDER IMPLICATIONS OF THE FINDINGS

The supra-physiological levels of estradiol generated during ovarian stimulation were significantly suppressed in the intervention group. However, UPF prior to fresh ET was similar in both groups. Modulating the luteal phase sex steroids with adjuvant letrozole had little measured impact on UPF. Any beneficial effect of adjuvant letrozole during ovarian stimulation is unlikely to be due to significant modulation of UPF.

STUDY FUNDING/COMPETING INTEREST(S)

MDH's salary was funded by an unrestricted research grant from Gedeon Richter. The expenses of the study was funded by a scientific collaboration: ReproUnion, co-financed by the European Union, Interreg Öresund-Kattegat-Skagerrak and Ferring Pharmaceuticals. The assays for the analyses were funded by Roche Diagnostics and an unrestricted research grant from Merck Life Science AS, Denmark. The authors have no competing interests to declare regarding this study.

TRIAL REGISTRATION NUMBER

Clinicatrials.gov: NCT02939898, EudraCT no.: 2015-005683-41.

Mode Switch of Ca2 + Oscillation-Mediated Uterine Peristalsis and Associated Embryo Implantation Impairments in Mouse Adenomyosis

Adenomyosis is a debilitating gynecological disease of the uterus with no medicinal cure. The tissue injury and repair hypothesis for adenomyosis suggests that uterine hyperperistalsis or dysperistalsis plays a pivotal role in establishing adenomyotic lesions. However, specific impairments in uterine peristalsis and the underlying cellular signals for these changes in adenomyosis remain elusive. Here, we report a precision-cut uterine slice preparation that preserves in vivo uterine architecture and generates peristalsis similar to that seen in the whole uterus. We found that uterine peristalsis in neonatal mice at day 14 and adult mice at day 55 presents as bursts with multiple peaks induced by intracellular Ca²⁺ oscillations. Using a mouse model of adenomyosis induced by tamoxifen, a selective estrogen receptor modulator, we discovered that uterine peristalsis and Ca²⁺ oscillations from adenomyotic uteri on days 14 and 55 become spikes (single peaks) with smaller amplitudes. The peak frequency of Ca²⁺ oscillations or peristalsis does not show a difference between control and adenomyotic mice. However, both the estimated force generated by uterine peristalsis and the total Ca²⁺ raised by Ca²⁺ oscillations are smaller in uteri from adenomyotic mice. Uteri from adenomyotic mice on day 14, but not on day 55, exhibit hyperresponsiveness to oxytocin. Embryo implantations are decreased in adenomyotic adult mice. Our results reveal a mode switch from bursts to spikes (rather than an increased peak frequency) of uterine Ca²⁺ oscillations and peristalsis and concurrent hyperresponsiveness to oxytocin in the neonatal stage are two characteristics of adenomyosis. These characteristics may contribute to embryo implantation impairments and decreased fertility in adenomyosis.

Biomechanics of the human uterus

The appropriate biomechanical function of the uterus is required for the execution of human reproduction. These functions range from aiding the transport of the embryo to the implantation site, to remodeling its tissue walls to host the placenta, to protecting the fetus during gestation, to contracting forcefully for a safe parturition and postpartum, to remodeling back to its nonpregnant condition to renew the cycle of menstruation. To serve these remarkably diverse functions, the uterus is optimally geared with evolving and contractile muscle and tissue layers that are cued by chemical, hormonal, electrical, and mechanical signals. The relationship between these highly active biological signaling mechanisms and uterine biomechanical function is not completely understood for normal reproductive processes and pathological conditions such as adenomyosis, endometriosis, infertility and preterm labor. Animal studies have illuminated the rich structural function of the uterus, particularly in pregnancy. In humans, medical imaging techniques in ultrasound and magnetic resonance have been combined with computational engineering techniques to characterize the uterus in vivo, and advanced experimental techniques have explored uterine function using ex vivo tissue samples. The collective evidence presented in this review gives an overall perspective on uterine biomechanics related to both its nonpregnant and pregnant function, highlighting open research topics in the field. Additionally, uterine disease and infertility are discussed in the context of tissue injury and repair processes and the role of computational modeling in uncovering etiologies of disease. WIREs Syst Biol Med 2017, 9:e1388. doi: 10.1002/wsbm.1388 For further resources related to this article, please visit the WIREs website.

Multiple-embryo transfer for studying very early maternal-embryo interactions in cattle

In the present paper, we highlight the need to study very early maternal-embryo interactions and discuss how these interactions can be addressed. Bovine species normally carry one or, less frequently, two embryos to term; there are very rare cases of triplets or higher-order multiple pregnancies in which all the offspring are born alive. Multiple-embryo transfer (MET) in cattle allows for the detection of endometrial responses in scenarios where single-embryo transfer would not. Although MET is non-physiological, the present study shows that at the very early embryonic stages, a uterus carrying zona-enclosed embryos does not exhibit non-physiological reactions. On the contrary, MET should be considered the sum of multiple individual effects triggered by developing embryos. We provide arguments to support our hypothesis that describe a rationale for current work with MET, and we discuss alternative hypotheses. Using cattle as a model, we describe how technical approaches to analyzing zona-enclosed early embryo-maternal interactions (i.e., transcriptomics, proteomics, and endometrial cell culture) can help identify molecular changes that may be difficult to observe when only a single embryo is present. We conclude that MET can be used for studying very early maternal-embryo interactions in vivo in monotocous species. Free Spanish abstract: A Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/150/2/R35/suppl/DC1.

Uterine morphology and peristalsis in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with chronic oligo-anovulation and high circulating sex hormone levels. Women with PCOS have an increased risk of developing endometrial cancer. In anovulatory women with PCOS a positive relationship between endometrial thickness and endometrial hyperplasia has been observed. Uterine peristalsis, which has been suggested to be of importance for female fertility, has not previously been studied in PCOS.

PURPOSE

To assess whether women with PCOS have altered endometrial thickness, uterine wall morphology, and peristalsis.

MATERIAL AND METHODS

In this prospective case-control study 55 women with PCOS (mean age, 29.5 years ± 4.5 SD) and 28 controls (27.6 ± 3.2) were examined using magnetic resonance imaging (MRI), assessing thickness of endometrium, junctional zone (JZ), and myometrium, and evaluating the occurrence, frequency (waves/min), strength (amplitude), pattern, and direction of peristalsis. Uterine morphology was also assessed by transvaginal ultrasonography (TVUS).

RESULTS

The endometrium was thinner in PCOS with oligo-amenorrhea compared to controls, also after adjustments for age and BMI (adjusted P = 0.043). There was no difference in thickness of the JZ or the myometrium in cases versus controls. Uterine peristalsis was less commonly observed in women with PCOS than in controls (adjusted P = 0.014).

CONCLUSION

There were no differences in myometrial morphology between PCOS and controls, but the endometrium was thinner in PCOS with oligo-amenorrhea. Based on cine MRI, uterine peristalsis was less common in PCOS than in controls.

A new method for analysis of non-pregnant uterine peristalsis using transvaginal ultrasound

OBJECTIVES

To develop an objective method for analysis of uterine peristalsis using transvaginal sonography (TVS).

METHODS

We performed computerized analysis of 2-5-min video recordings of TVS imaging of a midsagittal cross-section of the uterus during the proliferative and early secretory phases of 18 healthy volunteers aged 28-41 years. The contours of the fluid-endometrial interface (FEI) and the endometrium-myometrium interface (EMI) were detected in each frame, and the data from all frames were used to explore the dynamic motility characteristics of these interfaces at fixed distances from the fundus.

RESULTS

The mean ± SD dominant frequency of peristalsis of the EMI along the midsagittal cross-section was 0.049 ± 0.01 Hz and that of the cavity center was 0.043 ± 0.02 Hz. The maximal amplitudes of the EMI were about 1 ± 0.25 mm, located between 7 and 17 mm from the fundus. The amplitudes of the FEI were in the range 0.05-0.2 mm. The amplitude of the cavity centerline movement was 0.94 ± 0.34 mm, located at the extremes of the unperturbed curve.

CONCLUSIONS

This study provides a simple tool for analysis of uterine peristalsis characteristics using ultrasound data. This is possible at the EMI even when the FEI is invisible or incomplete, such as during the luteal phase, when an intrauterine contraceptive device is in place, and during diagnostic or medical intervention.

Effect of short-term, low-dose treatment with tamoxifen in patients with primary dysmenorrhea

Current treatment of painful periods and other symptoms related to primary dysmenorrhea (PD) is usually commenced with non-steroidal anti-inflammatory drugs or oral contraceptives, which fails in about 10% of affected patients. Tamoxifen, a selective estrogen-receptor modulator (SERM), has been demonstrated to directly inhibit uterine contractions, causing improvement in uterine blood flow. It could be considered for application in selected groups of dysmenorrheic patients, for instance carriers of breast cancer-associated antigen (BRCA) genes, breast cancer survivors or women with advanced endometriosis. Thus the aim of the present study was to investigate the effect of short-term treatment with tamoxifen on PD and PD-related symptoms, as well as its direct effect on parameters of intrauterine pressure during the painful menstruation, in a group of dysmenorrheic patients. After two cycles of administration of tamoxifen we noted a significant decrease in bleeding together with reductions in the severity of menstrual cramps, diarrhea, headache, fatigue and anxiety. In intrauterine pressure assessments, tamoxifen significantly decreased propagation of uterine contractions. In conclusion, SERMs such as tamoxifen may constitute a therapeutic option in selected groups of patients, improving dysmenorrheic symptoms. Additionally to its receptor-mediated effects, tamoxifen was shown to exert a direct influence on uterine contractile activity that may explain the decrease of menstrual pain and cramps noted in the studied group.

Diminished pregnancy rates in endometriosis due to impaired uterotubal transport assessed by hysterosalpingoscintigraphy

OBJECTIVE

To investigate uterotubal transport by means of hysterosalpingoscintigraphy (HSSG) in women with and without endometriosis.

DESIGN

A prospective observational study.

SETTING

University Hospital, Department of Obstetrics and Gynaecology, Division of Reproductive Medicine and Gynaecologic Endocrinology with 350 in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) cycles and 400 intrauterine insemination (IUI) cycles/year.

POPULATION

Cases included 56 infertile women with laparoscopic proven endometriosis and patent fallopian tubes. Twenty-two women with partners suffering from male factor infertility served as controls.

METHODS

A diagnostic cycle incorporating HSSG was performed. Subsequently, patients underwent either four cycles of timed intercourse (TI) or IUI in order to achieve pregnancy. If pregnancy did not occur, IVF or ICSI was performed.

MAIN OUTCOME MEASURES

Evaluation of uterotubal transport capacity in women with endometriosis and healthy controls.

RESULTS

Patients suffering from endometriosis (group I) showed a significant reduction in physiologic uterotubal transport function: While 20 patients (36%) had ipsi- or bilateral uterotubal transport, there was pathological uterotubal transport contralateral to the dominant follicle or a complete failure of transport capacity (negative HSSG) in 36 patients (64%). In the controls (group II), transport function was significantly different: 15 of 22 patients (68%) revealed ipsi- and bilateral tubal demonstration, while 5 patients (22%) showed contralateral transport and 2 patients (10%) showed negative HSSG (P= 0.01). Twenty-three pregnancies were observed (pregnancy rate: 29%). Eleven out of 14 (79%) women with ipsi- or bilateral tubal transport function fell pregnant by means of TI or IUI. In seven of nine patients (78%) with a failure in tubal transport, pregnancy was achieved by IVF/ICSI, despite acceptable semen parameters (P= 0.01).

CONCLUSIONS

Endometriosis is significantly associated with a reduction in physiologic uterotubal transport capacity compared with controls. This resulted in diminished pregnancy rates even in women with normozoospermic partners. Therefore, IVF/ICSI may be required even when fallopian tubes are patent or semen quality is normal.

Predictive value of impaired uterine transport function assessed by negative hysterosalpingoscintigraphy (HSSG)

BACKGROUND

Hysterosalpingoscintigraphy (HSSG) has given insight into the dynamics of rapid sperm transport inside the female genital tract.

RESULTS

While there is an increase of an ipsilateral transport on the side bearing the dominant follicle in 70% of the subjects in the periovulatory phase, 15% of the patients do not demonstrate transport to the fallopian tubes (negative HSSG). In these patients the pregnancy rate achieved spontaneously or by intrauterine insemination is significantly reduced compared to the patients who showed an intact transport mechanism confirmed by positive HSSG. On the other hand, by means of assisted reproductive techniques (ART), pregnancy rates were higher in the group of patients showing negative HSSG (P < 0.0005).

CONCLUSIONS

Our data clearly indicate that HSSG is a helpful method to evaluate the integrity of the utero-tubal transport mechanism. As pregnancy rates remain low in patients with negative HSSG, this result should be considered as an indication for IVF-treatment even in patients with patent fallopian tubes and normozoospermia of the partner.

Uterine contractility and directed sperm transport assessed by hysterosalpingoscintigraphy (HSSG) and intrauterine pressure (IUP) measurement

BACKGROUND

Uterine peristalsis sustains sperm transport and can be detected by hysterosalpingoscintigraphy (HSSG). This study is the first to be designed to investigate utero-tubal transport function by HSSG and uterine contractility by intrauterine pressure measurement (IUP) consecutively on the same day in the periovulatory phase.

METHODS

Twenty-one female subjects (mean age 28.4 years) without a gynecologic history were examined sequentially by HSSG and IUP on the same day to evaluate uterine contractility in relation to the utero-tubal transport function. In HSSG, intact transport function was visualized by the rapid uptake of 99m-technetium-marked albumin aggregates through the female genital tract. In IUP, the frequency of uterine contractions (UC/min), amplitude of uterine contractions and basal pressure tone were detected via a intrauterine catheter. HSSG and IUP were embedded in cycle monitoring with measurement of LH and estradiol.

RESULTS

In HSSG, a positive transport of inert particles was assessed in 20 of 21 subjects, in 76% to the side of the dominant follicle or on both sides of the oviduct, and in 19% a strict contralateral transport could be observed. In only one subject (5%), no transport was assessed. The mean value of uterine contractions was 3.4 UC/min (SD +/- 0.7), the mean amplitude was 12.0 mmHg (SD +/- 4.25 mmHg). Basal pressure tone was 70.7 mmHg. There was a statistically significant correlation with estradiol levels: none of the subjects with less than 3 UC/min showed an estradiol level higher than 100 pg/mL; nearly every patient (one exception) with more than 3 UC/min had an estradiol level higher than 100 pg/mL (p < 0.0001, Fisher's exact test).

CONCLUSIONS

Intact periovulatory utero-tubal transport function can be documented by HSSG and is caused by directed uterine contractility, measured consecutively by IUP. Uterine contractility is influenced by rising estradiol levels. Directed uterine contractility and intact utero-tubal transport function are considered necessary for intact sperm transport, mainly to the side bearing the dominant follicle to maximize fertility.

Comparison of changes in uterine contraction frequency after ovulation in the menstrual cycle and in in vitro fertilization cycles

OBJECTIVE

To compare changes in uterine contraction (UC) frequency occurring after ovulation in the menstrual cycle and in IVF and to clarify UC anomalies encountered in IVF.

DESIGN

Prospective crossover trial.

SETTING

University infertility clinic.

PATIENT(S)

Six women seeking IVF for male factor infertility having regular menstrual cycles were studied during the menstrual cycle and IVF.

INTERVENTION(S)

Identification of LH surge in the menstrual cycle. Measurement of plasma E(2) and P levels and assessment of UC frequency by direct ultrasound visualization on the day of LH surge in the menstrual cycle and the day of hCG administration in IVF and every 2 days thereafter for 6 days.

MAIN OUTCOME MEASURE(S)

Uterine contraction (UC) frequency and plasma E(2) and P levels.

RESULT(S)

UC frequency was similar on the day of LH surge (5/minute) and hCG administration (5.3/minute). Establishment of uteroquiescence was more prompt in the menstrual cycle than in IVF, with lower UC frequency 4 days after LH surge compared with 4 days after hCG, while E(2) and P levels were higher in IVF. Six days after LH surge/hCG administration, UC frequency was low in the menstrual cycle and in IVF.

CONCLUSION(S)

High UC frequency in IVF at the time of ET results from delayed establishment of uteroquiescence after ovulation in IVF as compared with the menstrual cycle. In IVF, low UC frequency 6 days after hCG may contribute to the higher pregnancy rates observed with blastocyst transfers.

The usefulness of ultrasound guidance in frozen-thawed embryo transfer: a prospective randomized clinical trial

BACKGROUND

Recent randomized controlled trials have shown that implantation and pregnancy rates were improved with ultrasound-guided embryo transfer compared with clinical touch in fresh IVF cycles associated with supraphysiological ovarian steroid levels. However, the usefulness of ultrasound guidance in frozen-thawed embryo transfer where potential hormonal influences are lacking has not been appropriately investigated.

METHODS

A total of 184 consecutive patients undergoing thawed embryo transfer cycles with hormone replacement under pituitary suppression were randomized by computer-generated randomization table to two study groups: 93 had ultrasound-guided (group 1) and 91 had clinical touch (group 2) embryo transfer.

RESULTS

There was equal distribution between the two study groups with respect to the main demographic and baseline characteristics of the patients as well as the characteristics of both prior IVF cycles from which embryos were generated and cryopreserved-thawed embryo transfer cycles. However, both pregnancy and implantation rates in group 1 (34.4 and 19.8% respectively) were significantly higher than the corresponding values (19.7 and 11.9%) in group 2.

CONCLUSIONS

Ultrasound guidance in frozen-thawed embryo transfer significantly increases pregnancy and implantation rates.

The mechanism of hydrosalpinx in embryo implantation

BACKGROUND

Hydrosalpinx adversely affects embryo implantation and contributes to poor implantation rates post embryo transfer. Embryo transport depends on concomitant intrauterine fluid motion induced by uterine wall motility, the result of spontaneous myometrial contractions towards the fundus.

METHODS AND RESULTS

The uterine dynamics of five patients with hydrosalpinx were recorded and analysed by image-processing techniques: the frequency was higher while the amplitudes and passive widths were lower compared with healthy volunteers. The existing peristaltic activity should have induced intrauterine fluid flow; however, the recordings failed to show the expected transport of fluid bolus. This observation was supported by mathematical simulations based on the hypothesis that fluid accumulation in the Fallopian tube of a patient with hydrosalpinx increases tubal pressure and thereby induces a pressure gradient between the fundus and the cervix. This pressure gradient acts adversely to the cervix-to-fundus intrauterine peristalsis and generates reflux currents that may thrust embryos away from the implantation site.

CONCLUSIONS

The reflux phenomenon could explain the reduced implantation rate associated with hydrosalpinx. Resolution of the issue of whether the removal of a Fallopian tube with hydrosalpinx should be undertaken for improving IVF pregnancy rates should be accompanied by prospective randomized clinical trials.