Reproductive biology and IVF: ovarian stimulation and endometrial receptivity

Reproductive Outcomes of Dual Trigger versus hCG Alone in Women Undergoing In Vitro Fertilization with Fresh Embryo Transfer Cycles

Aim

To investigate the effect of the triggering method on the results of fresh embryo transfer in patients who underwent gonadotropin-releasing hormone antagonist cycles.

Methods

The study was conducted retrospectively at a university-based tertiary reproductive center. The sample consisted of a total of 295 patients, of whom 111 were in the human chorionic gonadotropin (hCG) trigger group and 184 were in the dual trigger group. The main outcome measure of this study was the live birth rate, and secondary outcomes were the implantation rate, clinical pregnancy rate, miscarriage rate, and good-quality embryo rate.

Results

Patient demographics and baseline characteristics did not significantly differ between the dual and hCG trigger groups. The results also indicated statistically nonsignificant differences between the two groups in terms of the number of oocytes retrieved (p > 0.05), the number of mature oocytes (p > 0.05), and the fertilization rate (p > 0.05). The number of good-quality embryos (p=0.002) was higher in the dual trigger group compared with the hCG trigger group. However, the rates of clinical pregnancy and live births did not significantly differ between the groups (p > 0.05).

Conclusions

Although the number of total and high-quality embryos obtained was higher in the dual trigger group, there were no significant differences between the two groups in terms of pregnancy outcomes. The fresh embryo transfer yielded similar rates of implantation and live births in both trigger groups.

Impact of growth hormone on IVF/ICSI outcomes and endometrial receptivity of patients undergoing GnRH antagonist protocol with fresh embryo transfer: a pilot study

Introduction

Gonadotropin-releasing hormone antagonist (GnRH-ant) protocol is widely used in the world for controlled ovarian hyperstimulation (COH). However, previous studies have shown that pregnancy outcomes of fresh embryo transfer with GnRH-ant protocol are not ideal. Current studies have demonstrated the value of growth hormone (GH) in improving the pregnancy outcome of elderly women and patients with diminished ovarian reserve, but no prospective studies have confirmed the efficacy of GH in fresh embryo transfer with GnRH-ant protocol, and its potential mechanism is still unclear. This study intends to evaluate the impact of GH on IVF/ICSI outcomes and endometrial receptivity of patients undergoing GnRH-ant protocol with fresh embryo transfer, and preliminarily explore the possible mechanism.

Methods

We designed a randomized controlled trial of 120 infertile patients with normal ovarian response (NOR) who will undergo IVF/ICSI from April 2023 to April 2025, at Department of Reproductive Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. The patients will be divided into the depot gonadotropin-releasing hormone agonist (GnRH-a) protocol group, GnRH-ant protocol control group, and GnRH-ant protocol plus GH intervention group at a ratio of 1:1:1 by block randomization design. Patients will be followed on enrollment day, trigger day, embryo transfer day, 7 days after oocytes pick-up, 15 days after embryo transfer, 28 days after embryo transfer, and 12 weeks of gestation. The primary outcome is the ongoing pregnancy rate. Secondary outcomes include the gonadotropin dosage, duration of COH, endometrial thickness and pattern, luteinizing hormone, estradiol, progesterone level on trigger day, numbers of retrieved oocytes, high-quality embryo rate, biochemical pregnancy rate, clinical pregnancy rate, implantation rate, ectopic pregnancy rate, early miscarriage rate, multiple pregnancy rate and incidence of moderate and severe ovarian hyperstimulation syndrome. The endometrium of certain patients will be collected and tested for endometrial receptivity.

Ethics and dissemination

The study was approved by the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology [approval number: TJ-IRB20230236; approval date: February 10, 2023]. The research results will be presented at scientific/medical conferences and published in academic journals.

Clinical trial registration

Chinese Clinical Trial Registry; identifier: ChiCTR2300069397.

An integrative analysis of endometrial steroid metabolism and transcriptome in relation to endometrial receptivity in in vitro fertilization patients

OBJECTIVE

To study the relationship between the steroid concentration in the endometrium, in serum, and the gene expression level of steroid-metabolizing enzymes in the context of endometrial receptivity in in vitro fertilization (IVF) patients.

DESIGN

Case-control study of 40 IVF patients recruited in the SCRaTCH study (NTR5342), a randomized controlled trial investigating pregnancy outcome after "endometrial scratching." Endometrial biopsies and serum were obtained from patients with a first failed IVF cycle randomized to the endometrial scratch in the midluteal phase of the natural cycle before the next fresh embryo transfer during the second IVF cycle.

SETTING

University hopsital.

PATIENTS

Twenty women with clinical pregnancy were compared with 20 women who did not conceive after fresh embryo transfer. Cases and controls were matched for primary vs. secondary infertility, embryo quality, and age.

INTERVENTION

None.

MAIN OUTCOME MEASURE(S)

Steroid concentrations in endometrial tissue homogenates and serum were measured with liquid chromatography-mass spectrometry. The endometrial transcriptome was profiled by RNA-sequencing, followed by principal component analysis and differential expression analysis. False discovery rate-adjusted and log-fold change >|0.5| were selected as the threshold for differentially expressed genes.

RESULT(S)

Estrogen levels were comparable in both serum (n = 16) and endometrium (n = 40). Androgens and 17-hydroxyprogesterone were higher in serum than that in endometrium. Although steroid levels did not vary between pregnant and nonpregnant groups, subgroup analysis of primary women with infertility showed a significantly lower estrone concentration and estrone:androstenedione ratio in serum of the pregnant group (n = 5) compared with the nonpregnant group (n = 2). Expression of 34 out of 46 genes encoding the enzymes controlling the local steroid metabolism was detected, and estrogen receptor β gene was differentially expressed between pregnant and nonpregnant women. When only the primary infertile group was considered, 28 genes were differentially expressed between pregnant and nonpregnant women, including HSD11B2, that catalyzes the conversion of cortisol into cortisone.

CONCLUSION(S)

Steroidomic and transcriptomic analyses show that steroid concentrations are regulated by the local metabolism in the endometrium. Although no differences were found in endometrial steroid concentration in the pregnant and nonpregnant IVF patients, primary women with infertility showed deviations in steroid levels and gene expression, indicating that a more homogeneous patient group is required to uncover the exact role of steroid metabolism in endometrial receptivity.

CLINICAL TRIAL REGISTRATION NUMBER

The study was registered in the Dutch trial registry (www.trialregister.nl), registration number NL5193/NTR5342, available at https://trialsearch.who.int/Trial2.aspx?TrialID=NTR6687. The date of registration is July 31, 2015. The first enrollment is on January 1, 2016.

[No improvement in live birth rate after luteal phase support by GnRH agonist]

OBJECTIVES

To evaluate the impact of adding a GnRH agonist (GnRH-a) in luteal phase support (LPS) on live birth rates in IVF/ICSI in antagonist protocols.

METHODS

In total, 341 IVF/ICSI attempts are analyzed in this retrospective study. Patients were divided into two groups: A f: LPS with progesterone alone (179 attempts) between March 2019 and May 2020; B: LPS with progesterone and an injection of triptorelin (GnRH-a) 0.1mg 6 days after oocyte retrieval (162 attempts) between June 2020 and June 2021. The primary outcome was live birth rate. The secondary outcomes were miscarriage rate, pregnancy rate and ovarian hyperstimulation syndrome rate.

RESULTS

The baseline characteristic are identical between the two groups except the infertility duration (longer in the group B). There was no significant difference between the two groups in live birth rate (24.1% versus 21.2%), pregnancy rate (33.3% versus 28.1%), miscarriage rate (4.9% versus 3.4%) and no increase the SHSO rate. The multivariate regression analysis after adjustment for age, ovarian reserve and infertility duration did not reveal a significant difference in live birth rate between the two groups.

CONCLUSION

In this study, the results showed no statistically significant association with the single injection of a GnRH-a in addition to progesterone on live birth rate in luteal phase support.

Efficacy of long-term pituitary down-regulation pretreatment prior to in vitro fertilization in infertile patients with endometriosis: A meta-analysis

Controversial conclusions have been made in previous studies regarding the influence of ultra-long gonadotropin-releasing hormone agonist (GnRH-a) in the reproductive outcomes of women with endometriosis who are undergoing in vitro fertilization/ intracytoplasmic sperm injection embryo transfer (IVF/ICSI-ET). An electronic search was conducted through PubMed, Embase, Cochrane Library, Web of Science, Elsevier ScienceDirect and Medline from inception until 10 September 2022. Only randomized studies were included. After the selection process, seven articles were eventually included in the meta-analysis. The pooling of the results showed the adverse effect of ultra-long protocol in terms of live birth rate (risk ratio (RR) = 0.53, 95% confidence intervals (CI): 0.31-0.9, P=0.02) and fertilization rate (RR = 1.18, 95% CI: 1.02-1.36, P=0.02). There was no statistical significance between the ultra-long protocol and long protocol of the rest outcome Indicators. The findings of this meta-analysis suggest that ultra-long GnRH-a does not appear to improve the results of IVF/ICSI treatment outcomes in patients with endometriosis.

High anti-Müllerian hormone (AMH) is associated with increased risks of ectopic pregnancy in women undergoing fresh embryo transfer cycle, a cohort study

BACKGROUND

Ectopic pregnancy is more common amongst assisted reproduction cycles and is a cause of significant maternal morbidity. Few predictive markers exist to help identify and modify risk of ectopic pregnancy in preparing for embryo transfer. The relationship between serum and AMH and ectopic pregnancy rate is unknown.

METHODS

This was a retrospective cohort study investigating women who underwent fresh embryo transfer cycles from January 2017 to December 2019 in Peking University Third Hospital. The primary outcome was ectopic pregnancy. Restricted cubic splines with four knots for AMH concentration (0-3, 3-6, 6-12, 12-max) were used to map out the non-linear relationship between the predicted ectopic pregnancy rate and the serum AMH concentration. Log binomial regression was used to test the crude risk ratio (cRR) and the adjusted risk ratio (aRR) after adjustment for confounders with 95% confidence intervals (CI) to determine the difference across various groups.

RESULTS

A total of 13,718 cycles in women undergoing fresh embryo transfer were eligible for analysis. The ectopic pregnancy rate was 1.3% per embryo transfer cycle initiated and 3.3% per pregnancy. Serum AMH concentrations were higher amongst women with ectopic pregnancy than in women with a confirmed intrauterine pregnancy or heterotopic pregnancy or who did not become pregnant (Mean levels: 4.0 ng/ml vs 3.2 ng/ml, 1.7 ng/ml, and 2.8 ng/ml). An AMH concentration of 7 ng/ml represented the best cut-off value to predict ectopic pregnancy. The ectopic pregnancy rate was 3.4% per cycle and 7.5% per pregnancy in women with AMH levels ≥ 7 ng/ml; and 1.2% per cycle and 2.9% per pregnancy in women with AMH levels < 7 ng/ml. Serum AMH concentration ≥ 7 ng/ml was associated with an increased risk of ectopic pregnancy in all fresh embryo transfer cycles started (aRR = 2.35 (1.45, 3.58)) as well in women who became pregnant (aRR = 2.23 (1.49, 3.33).

CONCLUSIONS

Baseline AMH concentration ≥ 7 ng/ml is associated with an increased risk of ectopic pregnancy in fresh embryo transfer cycles.

The association between embryo storage time and treatment success in women undergoing freeze-all embryo transfer

OBJECTIVE

To investigate the relationship between the embryo frozen time and live birth rate (LBR) in women having a freeze-all cycle.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PATIENT(S)

Women who underwent their first vitrified-warmed cycles from January 2013 to December 2019.

INTERVENTION(S)

Embryo storage time.

MAIN OUTCOME MEASURE(S)

The primary outcome was the LBR.

RESULT(S)

A total of 14,928 women were eligible for the analysis. Women with the frozen time of transferred embryos for 2-5 months were associated with a higher LBR compared with other groups. The results were confirmed by an inverted U curve in the restricted cubic splines before as well as after adjustment for covariables, which suggested that an embryo storage time of 3-4 months was associated with the highest LBR. Subgroup analyses demonstrated that the inverted U curve relationship between embryo storage time and LBR was only observed in women with the high response. Sensitivity analyses in women with at least one good-quality embryo for transfer, in women aged <36 years at embryo transfer, or in women with double cleavage embryo transfer showed that the association remained valid. The association was weakened in women with single blastocyst transfer probably because of the small sample size in these women.

CONCLUSION(S)

An inverted U-shaped relationship was found between embryo storage time and treatment success in women with high ovarian response in freeze-all embryo transfer cycles. Prolonged storage time of >6 months was associated with reduced pregnancy rates.

Endometrial factors in the implantation failure spectrum: protocol of a MUltidisciplinary observational cohort study in women with Repeated Implantation failure and recurrent Miscarriage (MURIM Study)

INTRODUCTION

Women with repeated implantation failure (RIF) and unexplained recurrent miscarriage (RM) are proposed to be at opposite ends of the implantation spectrum, with RM representing an overly receptive endometrium (implantation of genetically aberrant or poor-quality embryos) versus RIF representing an overly selective endometrium (no implantation even with good quality embryos). In both cases, often no explanation for reproductive failure can be found and although promising add-on treatments have been introduced, therapeutic options are frequently limited to supportive care. Both RM and RIF are multifactorial and research indicates that the interplay between steroidogenesis, uterine natural killer (uNK) cells and the microbiome determine the capacity of the endometrium to be a biosensor for invading embryos. Our objective is to elucidate whether there is a difference in endometrial receptivity parameters (ie, steroid metabolism, uNK cells and the microbiome) between women aged 18-38 years with reproductive failure (RIF and RM), and fertile controls.

METHODS AND ANALYSIS

Single-centre, observational cohort study. Endometrial biopsies, vaginal swabs and peripheral blood will be collected during the window of implantation and menstrual blood in the subsequent menstruation. The study parameters are the steroid profile (steroid levels and mRNA levels, protein expression and activity of steroid enzymes) in endometrial tissue and peripheral blood, as well as the activating or inhibitory phenotype of uNK cells based on receptor expression in menstrual blood and endometrial tissue and determination of the vaginal and endometrial microbiome using the inter spacer bacterial profiling technique.

ETHICS AND DISSEMINATION

The protocol is approved by the local medical ethical review committee at the Maastricht University Medical Centre. Findings from this study will be shared with the academic and medical community and the patient organisations to optimise and individualise medical care of patients with implantation failure and miscarriages.

TRIAL REGISTRATION NUMBER

NTR7571, registered 28 February 2019.

Live birth after letrozole as an adjunct to follicle-stimulating hormone versus follicle-stimulating hormone alone for ovarian stimulation in in vitro fertilisation cycles-study protocol for a randomised controlled trial

INTRODUCTION

In vitro fertilisation (IVF) is an effective infertility treatment but the live birth rate remains unsatisfactory. Ovarian stimulation by follicle-stimulating hormone (FSH) is routinely used in IVF and the resulting high serum estradiol levels may impair oocyte/embryo quality and endometrial receptivity. Letrozole, an aromatase inhibitor, can reduce serum estradiol levels following ovarian stimulation. We aim to test the hypothesis that co-treatment with letrozole reduces supraphysiological serum estradiol levels and improves endometrial receptivity, leading to a higher live birth rate of IVF. We are conducting a randomised controlled trial (RCT) to evaluate whether letrozole as an adjunct to FSH in IVF is superior to FSH alone in the live birth rate of fresh embryo transfer.

METHODS/DESIGN

This is an open-label randomised controlled superiority trial being performed in two assisted reproduction centres in China. Infertile women who have antral follicle count (AFC) before ovarian stimulation or on day 5 of ovarian stimulation ≥15 are randomly allocated in a 1:1 ratio to receive either letrozole and FSH or FSH alone in a GnRH antagonist protocol. Recruited women follow the standard operating procedures of the two centres. The primary outcome is the live birth rate of the fresh embryo transfer. Stimulation parameters, maternal side effects and obstetric and perinatal complications are secondary outcomes. The planned sample size is 900, i.e. 450 per group.

DISCUSSION

The present study is the first multicentre randomised study to compare the live birth rate of the fresh embryo transfer following ovarian stimulation by letrozole and FSH versus FSH alone in women with anticipated high ovarian responses.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02912988 . Registered on September 23, 2016. This trial protocol is version 2.0.

Poor ovarian response and the possible role of natural and modified natural cycles

About 20% of women undergoing in vitro fertilization struggle with poor ovarian response, indicating a poor prognosis related to low response following ovarian stimulation. Indeed, poor ovarian response, that is associated with both high cancelation rates and low live birth rates, still represents one of the most important therapeutic challenges in in vitro fertilization. In this context, natural cycle/modified natural cycle–in vitro fertilization, as a ‘milder’ approach, could be a reasonable alternative to high-dose/conventional ovarian stimulation in poor ovarian responders, with the aim to retrieve a single oocyte with better characteristics that may result in a single top-quality embryo, transferred to a more receptive endometrium. Moreover, modified natural cycle–in vitro fertilization may be cost-effective because of the reduced gonadotropin consumption. Several studies have been published during the last 20 years reporting conflicting results regarding the use of natural cycle/modified natural cycle–in vitro fertilization in women with poor ovarian response; however, while most of the studies concluded that mild stimulation regimens, including natural cycle/modified natural cycle–in vitro fertilization, have low, but acceptable success rates in this difficult group of patients, others did not replicate these findings. The aim of this narrative review is to appraise the current evidence regarding the use of natural cycle/modified natural cycle–in vitro fertilization in poor ovarian responders.

Ovarian stimulation in IVF couples with severe male factor infertility: GnRH antagonist versus long GnRH agonist

OBJECTIVE

To examine the efficacy of gonadotropin releasing hormone (GnRH) antagonist (GnRH-ant) protocol and the long GnRH agonist (GnRH-a) protocol during in vitro fertilization (IVF) therapy in patients with severe male infertile factors.

METHODS

A total of 983 women with severe male factor infertility undergoing IVF therapy from 2017 to 2020 at one center were retrospectively analyzed. Patients were divided into the GnRH-ant group (n=527) and the GnRH-a group (n=456) according to their ovarian stimulation protocols. Patient baseline characteristics, ovarian stimulation characteristics, and clinical pregnancy outcomes were compared between the groups. The live birth rate was considered the main pregnancy outcome.

RESULTS

GnRH-a group had a higher live birth rate compared with the GnRH-ant group (41.0% versus 31.3%, p=0.002). Moreover, the implantation (32.8% vs. 28.1%, p=0.033), biochemical pregnancy (52.4% versus 44.8%, p=0.017), clinical pregnancy (49.3% versus 39.7%, p=0.002) and ongoing pregnancy rates (43.2% vs. 34.9%, p=0.008) were higher in GnRH-a group. For patients with one embryo transferred, the GnRH-a group demonstrated higher live birth (37.0% vs. 19.4%, p=0.010) and ongoing pregnancy rate (38.9% vs. 24.5%, p=0.046) than the GnRH-ant group. Among patients with two embryos transferred, the live birth rate was also higher in the GnRH-a group than in the GnRH-ant group, with no statistical difference. No significant differences were observed in the biochemical abortion rate, clinical miscarriage rate, early miscarriage rate, late miscarriage rate, heterotopic pregnancy rate, twin pregnancy rate, and birth sex ratio between the two groups.

CONCLUSION

For individuals with severe male infertility undergoing IVF, the GnRH-a protocol is considered a more efficient and feasible strategy with a higher live birth rate compared to the GnRH-ant protocol, especially in single embryo transfer.

Systematic use of long-acting intramuscular progesterone in addition to oral dydrogesterone as luteal phase support for single fresh blastocyst transfer: A pilot study

OBJECTIVE

The need of luteal support after FET is no longer to be proven. Different routes of progesterone administration are available with interindividual differences in metabolization and serum progesterone levels, the latter being highly correlated with pregnancy and delivery rates. The administration of 2 different routes of progestogen significantly improves success rates in FET. The aim of the current study was to investigate the added value to combine intramuscular administration of progesterone to dydrogesterone in fresh embryo transfer.

METHODS

This is a retrospective study from prospectively collected data. Patient, aged between 18 and 43 years old, had received a fresh blastocyst transfer between January 2021 and June 2021. In the first group, all patients received only oral dydrogesterone 10mg, three times a day, beginning the evening of oocyte retrieval. In the second group, patients received, in addition to dydrogesterone, a weekly intramuscular injection of progesterone started the day of embryo transfer. Primary endpoint was ongoing pregnancy rate.

RESULTS

171 fresh single blastocyst transfers have been performed during this period. 82 patients were included in "dydrogesterone only" and 89 patients in "dydrogesterone + IM". Our two groups were comparable except for body mass index. After adjustment on BMI, our two groups were comparable regarding implantation rate, early pregnancy rate (46.1 versus 54.9, OR 1.44 [0.78; 2.67], p=0.25) miscarriage rate, ongoing pregnancy rate (30.3 versus 43.9, OR 1.85 [0.97; 3.53] p= 0.06).

CONCLUSION

Using systematically long acting intramuscular progesterone injection in addition to oral dydrogesterone as luteal phase support seems to have no significant impact on IVF outcomes when a single fresh blastocyst transfer is performed.

Optimizing estradiol level for gonadotrophin-releasing hormone antagonist initiation among patients with simple tubal factor infertility

OBJECTIVE

The aim of this study is to investigate the optimal estradiol (E₂) level on the day of gonadotropin-releasing hormone antagonist (GnRH-ant) initiation to maximize the clinical pregnancy rate (CPR) after fresh embryo transfer among patients with simple tubal factor infertility.

METHODS

A retrospective cohort study was conducted in the Reproductive Medicine Center, the Second Hospital of Hebei Medical University. A total of 1,493 IVF-ET cycles of patients diagnosed with single tubal factor infertility from August 2016 to August 2021 were included and equally allocated into five distinct groups according to the quintile serum E₂ levels on the day of GnRH-ant initiation. The five groups had similar baseline data except for antral follicle count.

RESULTS

The serum E ₂ level on GnRH-ant initiation day was determined as an independent predictor of clinical pregnancy after adjusting for confounding factors such as age, infertility duration, body mass index, cycle number, antral follicle count, and the number of transferred embryos. Through smooth curve fitting, we found that, with the increase of serum E₂ levels on the day of GnRH-ant initiation, CPR showed a trend of slight increase and then slight decrease. The maximal CPR was achieved when the serum E₂ level on GnRH-ant initiation day was 498 pg/ml. When E₂ was less than 498 pg/ml, the odds ratio (OR) of clinical pregnancy was 1.05 (95% CI: 1.00, 1.11, P = 0.0583). When E₂ was greater than 498 pg/ml, the OR of clinical pregnancy was 0.97 (95% CI: 0.95, 0.98, P = 0.0003). Furthermore, CPR remained high when E₂ was 436.8-658.6 pg/ml but declined significantly by more than 40% when E₂ was ≥ 894.4 pg/ml (P < 0.05).

CONCLUSIONS

The serum E₂ level should be considered as an adjuvant parameter for GnRH-ant initiation. The best E₂ value was 498 pg/ml, and GnRH-ant administration could be recommended to initiate when serum E₂ was 436.8-658.6 pg/ml. If GnRH-ant was initiated when serum E₂ was above 894.4 pg/ml, then the CPR after fresh embryo transfer may decline dramatically, and thus, cancellation of fresh embryo transfer and earlier initiation of GnRH-ant in future cycles should be considered.

Long-term GnRH agonist pretreatment before frozen embryo transfer improves pregnancy outcomes in women with adenomyosis

RESEARCH QUESTION

Do frozen embryo transfer (FET) cycles following long-term gonadotrophin-releasing hormone agonist (GnRHa) pretreatment have better pregnancy outcomes than fresh embryo transfer cycles with long or ultra-long GnRHa protocol in these patients?

DESIGN

This study included 537 women with adenomyosis divided into three groups: (Group A) FET cycles following long-term GnRHa pretreatment (192 patients); (Group B) fresh embryo transfer cycles with the ultra-long GnRHa protocol (241 patients); (Group C) fresh embryo transfer cycles with the long GnRHa protocol (104 patients).

RESULTS

The total gonadotrophin dose and stimulation duration were significantly lower in Group A than in Groups B and C. The implantation and live birth rates were significantly higher in Group A than in Groups B and C. In the long-term GnRHa pretreatment and FET treatment of Group A, implantation (odds ratio [OR] 1.729, 95% confidence interval [CI] 1.073-2.788, P = 0.025), clinical pregnancy (OR 1.665, 95% CI 1.032-2.686, P = 0.037) and live birth rates (OR 1.694, 95% CI 1.045-2.746, P = 0.033) increased and miscarriage rate (OR 0.203, 95% CI 0.078-0.530, P = 0.001) decreased when compared with Group C. Comparison of Groups A and B showed that with the long-term GnRHa pretreatment, FET was a protective factor for live birth rate (OR 1.350, 95% CI 1.017-1.792, P = 0.038).

CONCLUSION

FET following long-term GnRHa pretreatment has a better IVF/intracytoplasmic sperm injection outcome, and a potential benefit in terms of a lower gonadotrophin dose, and a shorter stimulation duration than fresh embryo transfer combined with a long or ultra-long GnRHa protocol.

Ovarian stimulation reduces fetal growth by dysregulating uterine natural killer cells in mice

Ovarian stimulation is associated with a higher risk of low birth weight. However, the precise mechanisms by which ovarian stimulation increases the chances of low birth weight remain unclear. In this mouse model study, in vivo developed blastocysts that were not exposed to gonadotropins were transferred into pseudopregnant females that had mated naturally (the control group), pseudopregnant females that had been administered a low dose of ovulation-stimulating hormone (the L-SO group) and pseudopregnant females that had been administered a high dose of ovulation-stimulating hormone (the H-SO group). The embryo implantation rate and fetal weight were significantly lower in the L-SO and H-SO groups than in the control group. The density of Dolichos biflorus agglutinin (DBA)⁺ uterine natural killer (uNK) cells in the decidua basalis was significantly lower in the L-SO and H-SO groups than in the control group. Ovarian stimulation also downregulated a variety of cytokines related to uNK cells that are involved in placental angiogenesis and trophoblast invasion. Collectively, our findings indicate that ovarian stimulation impairs DBA⁺ uNK cell density in the decidua basalis, which may downregulate uNK-related cytokine secretion and influence placental angiogenesis and restrict fetal growth in mice.

The influence of frozen-thawed and fresh embryo transfer on utero-placental (vascular) development: the Rotterdam Periconception cohort

STUDY QUESTION

Does frozen-thawed or fresh embryo transfer (ET) influence utero-placental (vascular) development, when studied using three-dimensional (3D) ultrasound and virtual reality imaging techniques?

SUMMARY ANSWER

In the first trimester, placental developmental parameters, that is, placental volume (PV) and utero-placental vascular volume (uPVV), were comparable between pregnancies resulting from frozen-thawed ET, fresh ET and natural conception; and in the second and the third trimester, uterine artery Doppler indices were lower in pregnancies after frozen-thawed ET compared to pregnancies after fresh ET and natural conception.

WHAT IS KNOWN ALREADY

Pregnancies after frozen-thawed ET are at risk of developing placenta-related pregnancy complications. There is strong evidence that impaired first-trimester spiral artery remodelling is involved in the pathophysiology of these complications. Studies on longitudinal placental development in pregnancies with different modes of conception, that is, after frozen-thawed ET, fresh ET or natural conception, are lacking.

STUDY, DESIGN, SIZE, DURATION

Women with singleton pregnancies were included before 10 weeks of gestation, between January 2017 and July 2018, as a subcohort of the ongoing Rotterdam Periconception cohort. Results were partially validated in 722 women from the total cohort, which was conducted from November 2010 onwards.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 214 women, of whom 32 conceived after frozen-thawed ET, 56 conceived after fresh ET and 126 conceived naturally, were selected. PV and uPVV measurements were obtained at 7, 9 and 11 weeks of gestation by transvaginal 3D (power Doppler) ultrasound. The uterine artery pulsatility index (UtA-PI) and resistance index (UtA-RI) were measured transvaginally at 7, 9, 11 and 13 weeks and abdominally at 22 and 32 weeks of gestation by pulsed wave Doppler ultrasound. In the validation cohort, the PV was measured in 722 women. Associations between mode of conception and placental development were studied using linear mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

First-trimester parameters of placental development, that is, PV, uPVV, UtA-PI and UtA-RI, were comparable between pregnancies after frozen-thawed and fresh ET and naturally conceived pregnancies. In our validation cohort, comparable results were found for PV. However, the second- and third-trimester UtA-PI and UtA-RI in pregnancies after frozen-thawed ET were significantly lower than in pregnancies after fresh ET (β_UtA-PI −0.158 (95% CI: −0.268, −0.048), P = 0.005; β_UtA-RI −0.052 (95% CI: −0.089, −0.015), P = 0.006). The second- and third-trimester uterine artery indices in pregnancies after fresh ET were comparable to those in pregnancies after natural conception.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is the lack of power to optimally detect differences in placental development and placenta-related pregnancy outcomes between pregnancies after different modes of conception. Moreover, our population was selected from a tertiary hospital and included a relatively limited number of pregnancies. Therefore, external validity of the results should be confirmed in a larger sample size.

WIDER IMPLICATIONS OF THE FINDINGS

These findings indicate no significant impact of conception mode on early placental development and a beneficial impact for frozen-thawed ET on the second- and third-trimester Doppler indices. This suggests that frozen-thawed ET may not be as detrimental for placental perfusion as previous research has demonstrated. As the number of clinics applying the ‘freeze-all strategy’ increases, future research should focus on establishing the optimal uterine environment, with regards to hormonal preparation, prior to ET to reduce placental-related pregnancy complications after frozen-thawed ET.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the Erasmus MC Medical Research Advisor Committee’s ‘Health Care Efficiency Research’ program and the department of Obstetrics and Gynaecology of the Erasmus MC, University Medical Center, Rotterdam, The Netherlands. JSEL reports grants and personal fees from Ferring, personal fees from Titus Healthcare, grants and personal fees from Ansh Labs, grants from NIH, grants from Dutch Heart Association and grants from ZonMW outside the submitted work. None of the other authors have a conflict of interest.

TRIAL REGISTRATION NUMBER

Registered at the Dutch Trial Register (NTR6684).

Prenatal growth trajectories and birth outcomes after frozen-thawed extended culture embryo transfer and fresh embryo transfer: the Rotterdam Periconception Cohort

RESEARCH QUESTION

Are there differences in prenatal growth trajectories and birth outcomes between singleton pregnancies conceived after IVF treatment with frozen-thawed extended culture embryo transfer at day 5, fresh embryo transfer at day 3 or naturally conceived pregnancies?

DESIGN

From a prospective hospital-based cohort, 859 singleton pregnancies were selected, including 133 conceived after IVF with frozen-thawed embryo transfer, 276 after fresh embryo transfer, and 450 naturally conceived pregnancies. Longitudinal 3D ultrasound scans were performed at 7, 9 and 11 weeks of gestation for offline crown-rump length (CRL) and embryonic volume measurements. Second trimester estimated fetal weight was based on growth parameters obtained during the routine fetal anomaly scan at 20 weeks of gestation. Birth outcome data were collected from medical records.

RESULTS

No differences regarding embryonic growth trajectories were observed between frozen-thawed and fresh embryo transfer. Birthweight percentiles after fresh embryo transfer were lower than after frozen-thawed embryo transfer (38.0 versus 48.0; P = 0.046, respectively). The prevalence of non-iatrogenic preterm birth (PTB) was significantly lower in pregnancies resulting from fresh embryo transfer compared with frozen-thawed embryo transfer (4.7% versus 10.9%; P = 0.026, respectively). Compared with naturally conceived pregnancies, birthweight percentiles and percentage of non-iatrogenic PTB were significantly lower in pregnancies after fresh embryo transfer and gestational age at birth was significantly higher.

CONCLUSIONS

This study shows that embryonic growth is comparable between singleton pregnancies conceived after fresh and frozen-thawed embryo transfer. The lower relative birthweight and PTB rate in pregnancies after fresh embryo transfer than after frozen-thawed embryo transfer and naturally conceived pregnancies warrants further investigation.

A systematic review of clinical efficacy of frozen-thawed embryos and fresh embryos in in-vitro fertilization cycles

BACKGROUND

Frozen-thawed embryo (FTE) and fresh embryo (FE) transfer are two common strategies in vitro fertilization (IVF), while the results and findings still vary among studies.

METHODS

We searched multiple databases for relevant studies comparing the clinical effects of FTE and FE. Meta-analyses were conducted with Review Manager 5.0 to assess the efficacy among included articles. We also analyzed the risk of bias for the reports.

RESULTS

Nine studies eventually met the inclusion criteria from 2010 to 2018, and 11396 patients were included. The meta-analyses indicated no significant difference in biochemical pregnancy, clinical pregnancy and ongoing pregnancy rates. Meanwhile, the implantation rate and live birth rate in frozen-thawed embryos were much higher than those of fresh embryo. The birth weight in the frozen-thawed ET group was greater than that of the FE group, and the low birth weight rate in FTE was lower than FE group.

CONCLUSION

Our findings suggested a trend toward favouring frozen-thawed FTE might be a preferred transfer strategy for patients with IVF.

Expression of E-Cadherin in Pig-Tailed Monkey (Macaca nemestrina) Endometrium after Controlled Ovarian Hyperstimulation

An increase of steroid hormones in controlled ovarian hyperstimulation (COH) procedures is reducing the success rate in assisted reproductive technology (ART), and this includes the pregnancy rate and/or implantation rate. Research has found that the decrease in the success rate occurred due to the decreased expression of the protein that is needed to prepare the endometrium so that the embryo could attach. The aim of the study was to analyse the changes in E-chaderin expression due to COH and its relations with increased level of steroid hormones as one of the proteins in the endometrium. There were 13 samples of stored biological tissue from Macaca nemestrina endometrial tissue; came from one group of natural cycles as the control group (n = 4) and three groups of stimulated cycles. The first stimulated cycle group was injected by a 30 IU dose of rFSH (n = 2). The second stimulated cycle group was injected by a 50 IU dose of rFSH (n = 4). The third stimulated cycle group was injected by a 70 IU dose of rFSH (n = 3). The expression of E-cadherin was measured by the immunohistochemistry (IHC) technique. Estradiol (E2) and progesterone (P4) levels were assessed using ELISA and have already been done. The IHC staining expression of E-cadherin was found in the cytoplasm of glandular epithelium. Immunostaining measurement used the H_SCORE. We found that the expression of E-cadherin within the group was not significantly different (p value: 0.178). Similarly, both the correlation between the estradiol level with E-cadherin and the correlation between the progesterone level with E-cadherin were not significantly different (p value: 0.872 and p value: 0.836). The conclusion is that the level of E-Cadherin expression in the endometrium that were taken in themiddle secretion phase not affected by the dose regimen that given. In addition, the level of expression is not influenced by the increase of serum E2 and P4 levels.

Placentation in Equids

This chapter focuses on the early stages of placental development in horses and their relatives in the genus Equus and highlights unique features of equid reproductive biology. The equine placenta is classified as a noninvasive, epitheliochorial type. However, equids have evolved a minor component of invasive trophoblast, the chorionic girdle and endometrial cups, which links the equine placenta with the highly invasive hemochorial placentae of rodents and, particularly, with the primate placenta. Two types of fetus-to-mother signaling in equine pregnancy are mediated by the invasive equine trophoblast cells. First, endocrinological signaling mediated by equine chorionic gonadotrophin (eCG) drives maternal progesterone production to support the equine conceptus between days 40 and 100 of gestation. Only in primates and equids does the placenta produce a gonadotrophin, but the evolutionary paths taken by these two groups of mammals to produce this placental signal were very different. Second, florid expression of paternal major histocompatibility complex (MHC) class I molecules by invading chorionic girdle cells stimulates strong maternal anti-fetal antibody responses that may play a role in the development of immunological tolerance that protects the conceptus from destruction by the maternal immune system. In humans, invasive extravillous trophoblasts also express MHC class I molecules, but the loci involved, and their likely function, are different from those of the horse. Comparison of the cellular and molecular events in these disparate species provides outstanding examples of convergent evolution and co-option in mammalian pregnancy and highlights how studies of the equine placenta have produced new insights into reproductive strategies.

GnRH Antagonist Protocol With Cessation of Cetrorelix on Trigger Day Improves Embryological Outcomes for Patients With Sufficient Ovarian Reserve

OBJECTIVE

To evaluate the efficiency and validity of cessation of cetrorelix on trigger day during gonadotropin releasing hormone antagonist (GnRH-ant)-controlled ovarian stimulation of in vitro fertilization (IVF) cycles.

METHODS

In this retrospective study, a total of 1271 patients undergoing initial IVF cycles following the GnRH-ant protocol were enrolled; 832 patients received cetrorelix on trigger day (Group A) and 439 patients ceased cetrorelix on trigger day (Group B). We compared demographic characteristics, embryological and clinical outcomes between the two groups. A Poisson regression model was used to identify factors that significantly affected embryological outcomes. Patients were further divided into subgroups according to anti-Mullerian hormone (AMH) and age, to assess associations between ceasing cetrorelix on trigger day and embryological outcomes.

RESULTS

There was a significant improvement on embryological outcomes in patients who ceased cetrorelix on trigger day, and there were no significant differences in clinical outcomes or preovulation rates between the two groups. Furthermore, for patients with 1.1 ≤ AMH ≤ 4.7 ng/ml, all embryological outcomes were significantly higher in Group B compared with Group A. For patients with AMH > 4.7 ng/ml, the number of oocytes retrieved, fertilization rate (2PN) of IVF cycles and proportion of day 3 good quality embryos were all significantly higher in Group B. For patients with age < 35 years, all the embryological outcomes, besides the number of available embryos, were significantly higher in Group B than in Group A. There were no differences in embryological outcomes between the two groups when patients were stratified based on age > 35 years or AMH < 1.1 ng/ml.

CONCLUSION

GnRH-ant protocol with cessation of cetrorelix on trigger day improved embryological outcomes for young patients or patients with sufficient ovarian reserve, and was effective at preventing preovulation.

Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction

Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.

Effects of waiting time between failed fresh cycle embryo transfer and the next frozen embryo transfer on pregnancy outcomes in assisted reproductive technology

OBJECTIVE

To explore how waiting time after failed fresh cycle embryo transfer affects the pregnancy outcomes of the next frozen embryo transfer (FET).

METHODS

A retrospective analysis was carried out on the data of women who had received at least one FET after a failed fresh embryo transfer between January 2013 to December 2019. The women were grouped based on the "time" of the first FET, referring to the period between a failed fresh embryo transfer and the beginning of the next cycle of FET. This time is divided into two classes: immediate (<90 days after the failed fresh embryo transfer) and delayed (≥90 days after failed fresh embryo transfer). The following parameters were investigated: clinical pregnancy rate; biochemical pregnancy rate; ectopic pregnancy rate; and non-pregnancy rate.

RESULTS

A total of 293 cases of fresh embryo transfer cycles were included. No significant differences in the number of obtained oocytes, total number of FET, and the total amount of gonadotropin were seen between the immediate and delayed fresh embryo transfer groups. The pregnancy outcomes of the two groups were similar.

CONCLUSION

The duration of waiting time between failed fresh embryo transfer and the next FET does not affect pregnancy outcomes.

Perinatal and maternal outcomes after frozen versus fresh embryo transfer cycles in women of advanced maternal age

OBJECTIVE

The delay of childbearing in women has become a worldwide issue in recent decades. The application of assisted reproductive technology in women of advanced maternal age (AMA) is increasing. Evidence on the safety and outcomes of frozen embryo transfer (FET) compared with fresh embryo transfer (ET) in AMA women is still lacking. Therefore, the objective of the present study was to compare perinatal and maternal outcomes after autologous FET and fresh ET cycles in women of AMA.

STUDY DESIGN

A retrospective study of 1663 FET and 3964 fresh ET cycles in reproductive medical centers from 2009 to 2014. Women who aged ≥35 years and had clinical pregnancies after autologous frozen or fresh ET were included. The main perinatal outcomes included birth weight, gestational age, rates of preterm birth, macrosomia, low birth weight (LBW), and very low birth weight. The main maternal outcomes included rates of hypertensive disorders of pregnancy, gestational diabetes mellitus, and preterm premature rupture of the membranes.

RESULTS

Women who underwent FET had an increased risk of hypertensive disorders of pregnancy [1.1 % vs. 0.4 %, adjusted OR (95 % CI): 2.76 (1.39-5.51); p = 0.004]. Singletons born after FET had significantly higher mean birth weight (3388.78 ± 538.47 vs. 3316.19 ± 549.08; p = 0.001). Furthermore, increased risk of macrosomia [13.5 % vs. 10.4 %, adjusted OR (95 % CI): 1.35 (1.07-1.71); p = 0.013] and decreased risk of LBW [3.6 % vs. 5.3 %, adjusted OR (95 % CI): 0.67 (0.45-1.00); p = 0.048] were found in singletons born after FET.

CONCLUSIONS

Perinatal risks of AMA patients are higher in FET than in fresh ET, including higher birth weight, risks of macrosomia in singleton births, and hypertensive disorders of pregnancy.

A visualized clinical model predicting good quality blastocyst development in the first IVF/ICSI cycle

RESEARCH QUESTION

Is it possible to establish a visualized clinical model predicting good quality blastocyst (GQB) formation for patients in their first IVF/intracytoplasmic sperm injection (ICSI) cycle?

DESIGN

A total of 4783 patients in their first IVF/ICSI cycle between January 2015 and December 2019 were retrospectively included and randomly divided into the training set (n = 3826) and the testing set (n = 957) in an 8:2 ratio. The least absolute shrinkage and selection operator (LASSO) regression was adopted to select the most critical predictors for GQB formation to construct a visualized nomogram model based on the data of patients in the training set. Receiver operating characteristic and calibration curves were used to evaluate the predictive accuracy and discriminative ability. The performance of the model was also validated on independent data from patients treated in the testing set.

RESULTS

Maternal age, maternal serum anti-Müllerian hormone (MsAMH) concentration and the number of oocytes retrieved were highlighted as critical predictors of GQB development and were incorporated into the nomogram model. Based on the area under the curve (AUC) values, the predictive ability for ≥1, ≥3 and ≥5 GQB were 0.831, 0.734 and 0.748, respectively. The calibration curve also showed high concordance between the observed and predicted results. The AUC for predicting ≥1, ≥3 and ≥5 GQB in the testing set were 0.805, 0.695 and 0.707, respectively, which were similar to those for the training set.

CONCLUSIONS

The visualized nomogram model provides great predictive value for GQB development in patients in their first IVF/ICSI cycle and can be used to improve clinical counselling.

Association between the number of top-quality blastocysts and live births after single blastocyst transfer in the first fresh or vitrified-warmed IVF/ICSI cycle

RESEARCH QUESTION

Is there an association between the total number of top-quality blastocysts (TQB) developed in the first IVF/intracytoplasmic sperm injection cycle (ICSI) and live births after a single blastocyst transfer (SBT)?

DESIGN

Pregnancy outcomes from 1336 infertile women who had undergone their first IVF/ICSI treatment and accepted a first-time embryo transfer with a single fresh or vitrified-warmed blastocyst between January 2016 and August 2018 were assessed retrospectively. The restricted cubic splines method was used to evaluate the association between the number of TQB, and ongoing pregnancies and live births.

RESULTS

A significant non-linear functional form was found between the number of TQB and the ongoing pregnancies and live births (P < 0.05). The odds of an ongoing pregnancy or live birth were similar, at about 11% or higher for each additional TQB up to five TQB (odds ratio [OR] 1.11; 95% confidence interval [CI] 1.01-1.21). After this, pregnancy outcomes nearly plateaued, indicating that the number of TQB was not related to pregnancy when it was greater than five.

CONCLUSIONS

The quantity of TQB available for transfer or cryopreservation can provide important predictors for pregnancy and live birth after the first embryo transfer cycle with a single blastocyst. This valuable information may assist with the future application of SBT.

Luteal Phase Support in IVF: Comparison Between Evidence-Based Medicine and Real-Life Practices

Background: Luteal phase support (LPS) in assisted reproduction cycles has been widely investigated in recent years. Although progesterone represents the preferential product for luteal phase supplementation in cycles with fresh embryo transfer, there is ongoing debate as to when to start, which is the best route, dosage and duration, and whether there is a place for additional agents. Nevertheless, fertility specialists do not always adhere to evidence-based recommendations in their clinical practice. The aim of this worldwide web-based survey is to document the currently used protocols for luteal phase support and appraisal tendencies of drug prescription behavior and to compare these to the existing evidence-based literature. Material and Methods: A questionnaire was developed and sent by secure e-mail to 1,480 clinicians involved in ART worldwide. One hundred and forty-eighth clinicians from 34 countries returned completed questionnaires. Results: Progesterone support is usually started on the day of oocyte retrieval. Eighty percent of clinicians applied the administration of vaginal progesterone only. Intramuscular progesterone was prescribed by 6%, while oral progestin or subcutaneous progesterone were each prescribed by 5% of clinicians, respectively. Progesterone was administered until 8-10 weeks' gestation by 35% and 12 weeks by 52% of respondents. Conclusions: Vaginal administration was the preferred route for luteal phase support. The reported emerging use of the oral route confirms the expected shift in clinical practice as a result of recent evidence showing a reassuring safety score of oral progestins. In spite of the lack of evidence supporting the continuation of luteal support until 12 weeks' gestation, this practice was adhered to by more than half of the clinicians surveyed, highlighting the difference between evidence-based medicine and real-life practices.

Administration effects of single-dose GnRH agonist for luteal support in females undertaking IVF/ICSI cycles: A meta-analysis of randomized controlled trials

The aim of the present meta-analysis was to evaluate the effects of the addition of single-dose gonadotropin-releasing hormone agonist (GnRHa) for luteal support on pregnancy outcomes in females partaking in in vitro fertilization or intracytoplasmic sperm injection cycles. In total, the studies were hand-searched from six electronic databases to compare the pregnancy outcomes between single-dose GnRHa administered as luteal phase support (GnRHa group) and regular luteal support (control group). In the GnRHa group, single-dose GnRH agonist were administered at 5/6 days after IVF/ICSI procedures. In the control group, single-dose GnRH agonist was not added during luteal phase support. Only randomized controlled trials were included. Sensitivity analysis was performed using Revman 5.3 software; the high heterogeneity identified in the present analysis was primarily caused by one study included. Following exclusion of this particular study, the meta-analysis results indicated significantly higher rates of ongoing pregnancy or live birth per transfer (P=0.002), clinical pregnancy per transfer (CPR; P=0.001) and multiple pregnancy per pregnancy (P=0.020) in the GnRHa group compared with those in the control group. Meta-analysis of a subgroup of trials with long-acting GnRH-a ovarian treatment protocols indicated that the rate of ongoing pregnancy or live birth (P=0.080), CPR (P=0.090) and multiple pregnancy per pregnancy (P=0.140) were not significantly different between the two groups. However, the results from trials that had used a multi-dose GnRH antagonist ovarian treatment protocol indicated a significantly higher ongoing pregnancy or live birth rate per transfer (P=0.010), CPR per transfer (P<0.0001) and multiple pregnancy rate per pregnancy (P=0.003) compared with those in the control group. The present results suggested that administration of single-dose GnRH agonist in the luteal phase may be an ideal choice for patients undergoing IVF/ICSI therapy.

The stimulation protocol in poor responder IVF; a minimal or high-dose stimulation? - A meta-analysis

Background To determine whether a minimal stimulation (MS) or high-dose stimulation (HDS) protocol is a better option for patients classified as poor ovarian responders (POR) in terms of reproductive and pregnancy outcomes. Materials and methods A database search for evaluation of the study outcome by using meta-analysis method was carried out. The primary outcome was the clinical pregnancy (CP) rate for each of two groups, namely, the MS and HDS groups. The secondary outcomes were the gonadotropin dose used, duration of stimulation, cancellation rate, number of oocytes retrieved, number of fertilized oocytes, number of embryos transferred and live birth rates. Results Across five databases, 4670 potential studies for further screening were selected. But ultimately only six studies, three RCTs and three retrospective or case control studies were selected that meet the Bologna criteria for POR. In all there were 624 cycles. Our meta-analysis indicated that the CP rates, cycle cancellation rates, durations of stimulation, numbers of oocytes fertilized and numbers of embryos transferred were not statistically significant. Clearly, the number of oocytes retrieved in the MS group was significantly lower than in the HDS group, while the HDS group consumed significantly higher doses of gonadotropins than the MS group. The live birth rates were significantly higher in the MS group than in the HDS group. Conclusion MS should be the first-line protocol for managing POR because the live birth rate is significantly higher, even with fewer oocytes retrieved.

The greater incidence of small-for-gestational-age newborns after gonadotropin-stimulated in vitro fertilization with a supraphysiological estradiol level on ovulation trigger day

Introduction

Reproductive scientists have postulated various risk factors for lower birthweight following conventional gonadotropin‐stimulated in vitro fertilization compared with spontaneously conceived children: parental factors (age, health, duration of subfertility and smoking habits); ovarian stimulation; laboratory procedures; the number of oocytes retrieved and the number of embryos transferred. Our aim was to investigate the impact of gonadotropin stimulation and serum estradiol level on the risk of a newborn being small‐for‐gestational‐age.

Material and methods

We conducted a cohort study (2010‐2016) of singletons (n = 155) born either after conventional gonadotropin‐stimulated in vitro fertilization (using ≥150 IU/d human gonadotropin for stimulation) or after natural cycle in vitro fertilization without any stimulation. We analyzed perinatal outcomes using birthweight percentiles, adjusted for gestational age and sex.

Results

The proportion of small‐for‐gestational‐age was 11.8% following conventional gonadotropin‐stimulated in vitro fertilization and 2.9% after natural cycle in vitro fertilization (P = 0.058). The odds of small‐for‐gestational‐age were significantly higher with supraphysiological estradiol levels in maternal serum on ovulation trigger day (unadjusted odds ratio 4.58; 95% confidence interval 1.35‐15.55; P = 0.015). It remained significant after adjusting for maternal height, age and body mass index (adjusted odds ratio 3.83; 95% confidence interval 1.06‐13.82; P = 0.041).

Conclusions

We found an associated risk of children being born small‐for‐gestational‐age after conventional gonadotropin‐stimulated in vitro fertilization compared with natural cycle in vitro fertilization. This higher risk is significantly associated with supraphysiological estradiol levels. We propose a reduction in the dosage of gonadotropin to minimize the risk of small‐for‐gestational‐age and future health consequences.

Clinically significant intra-day variability of serum progesterone levels during the final day of oocyte maturation: a prospective study with repeated measurements

STUDY QUESTION

Is there significant variability in progesterone levels during the final day of oocyte maturation in women undergoing ovarian stimulation?

SUMMARY ANSWER

Progesterone levels drop from the basal level up to 44% during the final day of oocyte maturation in women undergoing ovarian stimulation.

WHAT IS KNOWN ALREADY

It has been suggested that elevated progesterone levels on the final day of ovarian stimulation may be related to poorer outcomes in in vitro fertilization fresh cycles due to a negative impact on the endometrium. However, despite conflicting results regarding the actual effect of progesterone on pregnancy rates and the lack of a well-established cut off, currently many IVF patients have their embryo transfer deferred when progesterone values surpass a threshold of 1.5 ng/ml on the day of ovulation triggering.

STUDY DESIGN, SIZE, DURATION

This was a prospective cohort study conducted in 22 oocyte donors of a university-affiliated fertility centre between November 2017 and January 2018. We calculated the sample size to detect a difference of 15% between the first and last progesterone measurements with a 5% false-positive rate in a two-sided test with 80% statistical power and a 95% confidence interval (CI).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Progesterone circulating levels were evaluated at four different times during the final day of oocyte maturation (08:00, 12:00, 16:00 and 20:00) before ovulation triggering in healthy oocyte donors. A flexible antagonist protocol was used, and ovarian stimulation was achieved with recombinant follicle-stimulating hormone (FSH) in all cases. The pairwise percentage differences in progesterone levels for each patient were calculated. Univariate linear regression analysis was adopted in order to evaluate variables associated with progesterone levels on the first measurement. The intra-day variability of progesterone was analysed using mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean serum progesterone values at 08:00, 12:00, 16:00 and 20:00 were 1.75 ng/ml, 1.40 ng/ml, 1.06 ng/ml and 0.97 ng/ml. The progesterone difference between 08:00 and 20:00 was 0.77 (95% CI, 0.56–0.99), which is equivalent to a 44% decline in the mean progesterone values between the first (08:00) and the last determination (20:00; P < 0.001). Among those patients with basal (08:00) progesterone levels >1.5 ng/ml (n = 10), 70% (n = 7) showed levels reduced to <1.5 ng/ml on the last determination of the day (20:00). A mixed model analysis revealed that the progesterone reduction during the day was significantly associated with time and total recombinant FSH dose administered.

LIMITATIONS, REASONS FOR CAUTION

Only young healthy oocyte donors stimulated with an antagonist protocol using recombinant FSH were included. Extrapolation to the general IVF population, with different stimulation protocols and gonadotropins, needs to be confirmed.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that a single progesterone determination on the final day of oocyte maturation is not reliable enough to make clinical decisions due to the enormous variation in progesterone during the day. Further studies are needed to better define the impact of the follicular progesterone rise on the endometrium of IVF cycles.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was granted from Fundació Santiago Dexeus Font. N.P.P. received unrestricted grants and/or lectures fees from Roche Diagnostics, MSD, Merck, Ferring Pharmaceuticals, IBSA, Theramex and BESINS International, not associated with the current study. The remaining authors have no competing interests.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT03366025.

Clinical pregnancy (CP) and live birth (LB) increase significantly with each additional fertilized oocyte up to nine, and CP and LB decline after that: an analysis of 15,803 first fresh in vitro fertilization cycles from the Society for Assisted Reproductive Technology registry

OBJECTIVE

To study the association between the total number of fertilized oocytes available and pregnancy outcomes in first fresh IVF cycles with a single blastocyst transfer.

DESIGN

Retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 15,803 patients from SART reporting fertility clinics.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Primary outcomes were clinical pregnancy (CP), live birth (LB), and miscarriage rates. Logistic regression was used to investigate the association between the number of fertilized eggs and each outcome.

RESULT(S)

The median number of total oocytes was 15, and the median number of fertilized oocytes was nine. The odds of a clinical pregnancy were 8% higher for each additional fertilized oocyte up to nine (odds ratio [OR] 1.08; 95% confidence interval [CI] 1.07-1.10) and declined by 9% for every additional fertilized oocyte after nine (OR 0.91; 95% CI 0.89-0.94). Similarly, the odds of an LB was 8% higher for every additional fertilized oocyte up to none (OR 1.08; 95% CI 1.06-1.10) and declined by 8% for every additional fertilized oocyte over nine (OR 0.92; 95% CI 0.90-0.94).

CONCLUSION(S)

Odds of pregnancy outcomes (CP, LB) increase significantly with every additional fertilized oocyte up to nine, and CP and LB decline after that in first fresh autologous cycles with a single blastocyst transfer.

Comparative proteomics reveal negative effects of gonadotropin-releasing hormone agonist and antagonist on human endometrium

Purpose: The two major ovarian-stimulation protocols for in vitro fertilization are gonadotropin-releasing hormone agonist (GnRH-a) protocol or GnRH antagonist (GnRH-ant) protocol; however, comparisons of their relative efficacy remain controversial. Additionally, conflicting data exist regarding their effects on endometrial receptivity. Thus, this study investigated how GnRH-a and GnRH-ant treatments alter the endometrium during the mid-secretory phase.

Patients and methods: We compared proteomic profiles across human endometrium tissues of mid-secretory phase from normal control humans (n=5), patients treated with GnRH-a (n=5), and patients treated with GnRH-ant (n=5).

Results: We identified 2088 proteins, with 362 that exhibited significantly different expression. Fuzzy c-means clustering (FCM) using the M Fuzz algorithm analysis showed that the same 87 proteins changed significantly in both the GnRH-a and GnRH-ant groups compared with those in the control. Moreover, Gene Ontology (GO) analysis showed that, of these 87, downregulated proteins were associated with energy metabolism and upregulated proteins were linked to cytoskeleton maintenance. Upregulated proteins involved in complement-mediated immunity were present in 151 proteins that exhibited significantly different expression in the GnRH-ant group only.

Conclusion: We demonstrated that comparative proteomic analysis is useful for accessing endometrial receptivity, which seemed more strongly impaired by GnRH-ant than GnRH-a treatments. Our findings also revealed that energy metabolism and immunity response may be the key biological mechanisms underlying human endometrial receptivity.

The endometrium during and after ovarian hyperstimulation and the role of segmentation of infertility treatment

Controlled ovarian hyperstimulation (COH) is a crucial part of assisted reproductive technologies (ART) that resulted in a substantial increase in pregnancy rates from in vitro fertilization (IVF). However, in spite of the apparent benefit of COH on an increase in the number of follicles and the number of oocytes retrieved, allowing for extended embryo culture and enabling the selection of the best quality embryo for transfer, several reports has shown that the supraphysiologic hormonal levels may indeed have a detrimental effect at the endometrial level. The current article revises the pathophysiological mechanisms through which ovarian stimulation may negatively affect endometrial receptivity. Also, the evidence is analyzed explaining how segmentation of IVF treatment may allow us to overcome the deleterious effects of hyperstimulation on endometrial receptivity. Deferred embryo transfer may be performed in a more physiologic uterine environment in a subsequent cycle, improve endometrial receptivity, decrease uterine contractility, diminishes the impact of premature luteinization and allow individualized stimulation according to the level of response.

Calcitonin administration improves endometrial receptivity via regulation of LIF, Muc-1 and microRNA Let-7a in mice

Calcitonin (CT) is one of the factors affecting the embryo implantation, but its effects on the implantation window have not been fully investigated. The current study investigated the effects of CT on the endometrium receptivity by morphological study and evaluation of leukemia inhibitory factor (LIF), mucin 1 (Muc-1), and microRNA (miRNA) Let-7a in the ovarian stimulation and the normal ovarian cycle. Then the mechanism of the CT effects through the mammalian target of rapamycin (mTOR) signaling pathway was studied by using PP242. A total of 64 BALB/c mice were divided into the normal ovarian cycle and ovarian stimulation groups. Each group consisted of four subgroups: control, calcitonin, PP242, and calcitonin+PP242. CT and PP242 were injected on the fourth of pregnancy into the mice and 24 hr later all the mice were killed. The uterine tissue samples were used for morphological analysis, and endometrial cells were mechanically isolated for evaluation of gene and protein expression. The results showed that ovarian stimulation induced mTOR phosphorylation as well as increased expression of the Let-7a miRNA. In addition, CT injection increased the expression of LIF and miRNA Let-7a in ovarian stimulation similar to that in normal ovarian cycles. However, injection of PP242 reduced expression of miRNA Let-7a and increased Muc-1 expression in ovarian stimulation group. In conclusion, the administration of CT improved endometrial receptivity in mice. This phenomenon occurred by upregulation of LIF, miRNA Let-7a and downregulation of Muc-1 via mTOR signaling pathway.

GnRH agonist long protocol versus GnRH antagonist protocol for various aged patients with diminished ovarian reserve: A retrospective study

This retrospective analysis compared the efficiency of the gonadotropin- releasing hormone (GnRH) antagonist (GnRH-ant) protocol and the GnRH agonist long (GnRH-a) protocol for patients with diminished ovarian reserve (DOR). A total of 1,233 patients with DOR (anti-Mullerian hormone <1.1 ng/mL) were recruited for this retrospective case-control study. They were divided into two groups according to female age. Younger patients were assigned to POSEIDON group3 (PG3: age ≤35 years); older patients were assigned to POSEIDON group 4 (PG4: age >35 years). All patients with DOR underwent controlled ovarian stimulation and fresh embryo transfer (ET) on day 3. We recruited 283 GnRH-a and 54 GnRH-ant cycles for PG3, and 663 GnRH-a and 233 GnRH-ant cycles for PG4. In PG3, the GnRH-a protocol was associated with a lower ET cancellation rate (30/283 = 10.2% vs. 12/54 = 22.2%, p = 0.018) and a higher live birth rate (7/54 = 13.0% vs. 78/283 = 27.6%, p = 0.024) than the GnRH-ant protocol for the initiated cycles. Furthermore, the GnRH-a protocol was correlated with a higher implantation rate than the GnRH-ant protocol for ET cycles (146/577 = 25.3% vs. 11/103 = 10.7%, P = 0.027). No differences in the ET cancellation rate, live birth rate and implantation rate between GnRH-a and GnRH-ant groups were observed among PG4 patients. In conclusion, the GnRH-a protocol was more effective than the GnRH-ant protocol for young patients with DOR. The low ET cancellation rate and high implantation rate may be related to embryo quality or endometrial receptivity, which warrant further investigation.

Superovulation alters the expression of endometrial genes critical to tissue remodeling and placentation

PURPOSE

Epidemiologic data suggest that in vitro fertilization (IVF) is associated with an increased risk of disorders of placentation including preeclampsia and fetal growth restriction. Specifically, studies have demonstrated that singleton pregnancies conceived following a fresh embryo transfer are at an increased risk of delivering an infant with low birth weight compared to those conceived following a frozen embryo transfer. The mechanism responsible for this association remains unclear. Procedures utilized in IVF have also been linked with epigenetic changes and gene expression changes in both fetal and maternal tissues. Data suggest that modifications in the maternal endometrium can lead to disordered trophoblast invasion and placentation. This study examines the effect of ovarian stimulation on endometrial gene expression and DNA methylation during the window of implantation to examine potential pathways playing a role in the adverse outcomes associated with IVF.

METHODS

Endometrial biopsies were obtained from oocyte donors and age-matched naturally cycling women 11 days following oocyte retrieval in donors or 12 days following luteinizing hormone (LH) surge in naturally cycling women. Global gene expression was analyzed via Affymetrix Human Gene 1.1 ST array and confirmed with RT-qPCR. DNA methylation was assessed with the Infinium DNA methylation 450 K BeadChip.

RESULTS

Analysis of endometrial gene expression from 23 women (11 oocyte donors and 12 controls) demonstrated 165 genes with a greater than twofold change in expression between donors and controls. While there were 785 genes with significant differential methylation in the endometrium of donors when compared with control subjects, none of the genes with altered expression showed significant changes in DNA methylation. Analysis of the differentially expressed genes showed enrichment for genes involved in endometrial remodeling including PLAT, HSPE2, MMP2, and TIMP1. Validation studies using RT-qPCR found a 73% reduction in expression of heparanase 2 (HSPE2) an enzyme associated with both angiogenesis and cell invasion, a greater than twofold increase in tissue-type plasminogen activator (PLAT), a serine protease participating in matrix degradation, and a 70% increase in MMP2, a gelatinase involved in collagen and fibronectin breakdown.

CONCLUSIONS

Superovulation alters expression of genes critical to endometrial remodeling during early implantation. Such changes could lead to altered trophoblast migration and impaired endovascular invasion. These findings offer a potential mechanism for the adverse perinatal outcomes observed following embryo transfer during fresh IVF cycles.

Does freeze-all policy affect IVF outcome in poor ovarian responders?

OBJECTIVE

To evaluate whether the freeze-all strategy affects in-vitro fertilization (IVF) outcome in poor ovarian responders (POR) defined according to the Bologna criteria.

METHOD

This was a retrospective cohort study of patients undergoing IVF treatment between January 2012 and December 2016 at a single center. A total of 433 POR (as defined by the Bologna criteria) fulfilled criteria and were included in the study; of these, 277 patients underwent fresh embryo transfer (ET) and 156 followed the freeze-all policy. All patients underwent controlled ovarian stimulation (COS) following a gonadotropin-releasing hormone antagonist protocol, and cleavage-stage ET. Main outcome measure was ongoing pregnancy rate. Secondary outcomes included implantation and clinical pregnancy rates. The freeze-all strategy was implemented when the progesterone serum level was > 1.5 ng/mL or the endometrium was < 7 mm on the trigger day, or as per patient preference. Patients with previous failed fresh ET also underwent fresh ET or freeze-all strategy considering the indications mentioned above.

RESULTS

Mean maternal age in the freeze-all group was 39.5 ± 3.6 years and in the fresh ET group was 39.7 ± 3.8 years (P = 0.54). Mean number of embryos transferred (nET) was 1.53 ± 0.6 and 1.60 ± 0.6 (P = 0.12) in the freeze-all and fresh ET groups, respectively. Ongoing pregnancy rate did not differ significantly between the freeze-all and fresh ET groups (9.6% vs 10.1%, respectively; relative risk (RR), 0.95; 95% CI, 0.52-1.73), nor did the clinical pregnancy rate (14.1% vs 13.7%, respectively; RR, 1.03; 95% CI, 0.63-1.67). Implantation rate was 9.6% and 9.8% (P = 0.82) in the freeze-all and fresh ET groups, respectively. Logistic regression analysis (including maternal age, antral follicle count, number of retrieved and mature oocytes, nET, and fresh ET vs freeze-all strategy) indicated that maternal age (P < 0.001) and nET (P = 0.039) were the only independent variables associated with ongoing pregnancy rate.

CONCLUSIONS

The freeze-all strategy, compared with fresh ET, had no impact on IVF outcomes in POR patients as defined according to the Bologna criteria. Multicenter studies including large numbers of patients should be carried out to confirm the results of this study and reach conclusions about the potential benefits of the freeze-all policy for poor responders. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Low dosing of gonadotropins in in vitro fertilization cycles for women with poor ovarian reserve: systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of low doses of gonadotropins and gonadotropins combined with oral compounds compared with high doses of gonadotropins in ovarian stimulation regimens in terms of ongoing pregnancy per fresh IVF attempt in women with poor ovarian reserve undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment.

DESIGN

A systematic review and meta-analysis of randomized controlled studies that evaluate the effectiveness of low dosing of gonadotropins alone or combined with oral compounds compared with high doses of gonadotropins in women with poor ovarian reserve undergoing IVF/ICSI treatment.

SETTING

Not applicable.

PATIENT(S)

Subfertile women with poor ovarian reserve undergoing IVF/ICSI treatment.

INTERVENTION(S)

We searched the PubMed, EMBASE, Web of Science, the Cochrane Library, and the Clinical Trials Registry using medical subject headings and free text terms up to June 2016, without language or year restrictions. We included randomized controlled studies (RCTs) enrolling subfertile women with poor ovarian reserve undergoing IVF/ICSI treatment and comparing low doses of gonadotropins and gonadotropins combined with oral compounds versus high doses of gonadotropins. We assessed the risk of bias using the criteria recommended by the Cochrane Collaboration. We pooled the results by meta-analysis using the fixed and random effects model.

MAIN OUTCOMES MEASURE(S)

The primary outcome was ongoing pregnancy rate (PR) per woman randomized.

RESULT(S)

We retrieved 787 records. Fourteen RCTs (N = 2,104 women) were included in the analysis. Five studies (N = 717 women) compared low doses of gonadotropins versus high doses of gonadotropins. There was no evidence of a difference in ongoing PR (2 RCTs: risk rate 0.98, 95% confidence interval 0.62-1.57, I² = 0). Nine studies (N = 1,387 women) compared ovarian stimulation using gonadotropins combined with the oral compounds letrozole (n = 6) or clomiphene citrate (CC) (n = 3) versus high doses of gonadotropins. There was no evidence of a difference in ongoing PR (3 RCTs: risk rate 0.90, 95% confidence interval 0.63-1.27, I² = 0).

CONCLUSION(S)

We found no evidence of a difference in pregnancy outcomes between low doses of gonadotropins and gonadotropins combined with oral compounds compared with high doses of gonadotropins in ovarian stimulation regimens. Whether low doses of gonadotropins or gonadotropins combined with oral compounds is to be preferred is unknown, as they have never been compared head to head. A health economic analysis to test the hypothesis that an ovarian stimulation with low dosing is more cost-effective than high doses of gonadotropins is needed.

PROSPERO REGISTRATION NUMBER

CRD42016041301.