Do serum progesterone levels on day of embryo transfer influence pregnancy outcomes in artificial frozen-thaw cycles?

Comparison of Individualized Rescue Luteal Phase Support Strategies with Vaginal and Combined Vaginal & Subcutaneous Progesterone Administration in Artificial Frozen-Thawed Blastocyst Embryo Transfer Cycles Based on Serum Progesterone levels

Objectives

Hormone replacement therapy (HRT) frozen embryo transfer (FET) cycles are common in assisted reproductive techniques. As the corpus luteum is absent in these cycles, luteal phase support is provided by administering progesterone (P4) through transvaginal, parenteral, or oral routes. Low serum levels of P4 (below 9-10 ng/mL) on the day before embryo transfer (ET) have been associated with unfavorable cycle outcomes. The aim of this study is to investigate whether individualizing luteal support through rescue protocols in patients with low serum P4 levels improves pregnancy outcomes in HRT-FET cycles.

Material and method

This retrospective, single-center cohort analysis includes 1257 cycles involving 942 patients undergoing HRT-FET. Starting in 2019, we have assessed P4 levels before ET day and adjusted MVP doses when P4 levels were <10 ng/mL. In 2021, subcutaneous (SC) P4 was routinely added alongside MVP, with SC doses increased if P4 levels were <10 ng/mL. In this study, Groups 1 and 2 received MVP for luteal support, while Groups 3 and 4 received additional SC progesterone. For patients with P levels below the cut-off level (10 ng/mL) in Groups 2 and 4, the P dose was doubled through a rescue protocol.

Results

In the MVP and MVP plus SC groups, 15.8% and 8.9% of the cycles had P4 levels <10 ng/mL, respectively. Ongoing pregnancy rates (OPR) and clinical pregnancy rates (CPR) did not differ between study groups. Regression analysis with a mixed model revealed that age, endometrial thickness, and estradiol levels were confounding factors as well as independent predictors of ongoing pregnancy rates (p<0.05). Pairwise regression analysis revealed no significant differences in pregnancy rates between the groups (p>0.05).

Conclusion

Individualizing luteal phase support based on serum P4 levels on the day of ET in FET cycles with HRT may enhance pregnancy outcomes by either doubling the vaginal dose or increasing the SC dose during MVP plus SC administration. The implemented rescue protocol allowed patients with low progesterone levels to achieve pregnancy outcomes similar to those with higher progesterone levels.

FSH/LH co-stimulation in Advanced Maternal Age (AMA) and hypo-responder patients - Arabian gulf delphi consensus group

Background

In a global effort to assess expert perspectives on the use of recombinant gonadotropins, recombinant human luteinizing hormone (r-hLH) and recombinant human follicle-stimulating hormone (r-hFSH), a consensus meeting was held in Dubai. The key aim was to address three critical questions: What are the factors that influence follicle response to gonadotropins? Which categories of patients are most likely to benefit from LH supplementation? And what are the optimal management strategies for these patients?

Methods

A panel of thirty-six experts reviewed and refined the initial statements and references proposed by the Scientific Coordinator. Consensus was defined as agreement or disagreement by more than two-thirds (66%) of the panel members for each statement.

Results

Thirty-five statements were formulated, of which thirty-one reached consensus. For patients with Hypo-Response to Gonadotropin Stimulation (20 statements), all identified risk factors, including advanced age, high BMI, and chronic conditions, achieved unanimous agreement. Diagnostic approaches, such as the inclusion of POSEIDON criteria and hormone level monitoring, were endorsed by the majority, with over 90% agreement. Management strategies, particularly individualized stimulation protocols and optimized scheduling, garnered broad consensus, with only one statement falling short of the threshold. Additionally, in cases of severe FSH and LH deficiency, combining r-hFSH with r-hLH was found to improve pregnancy rates and cost efficiency compared to human menopausal gonadotropin (hMG). For patients with Advanced Maternal Age (AMA) (15 statements), there was strong agreement on the use of oral contraceptive pills and estrogen priming. Recommendations concerning antagonist protocols and dosing of r-hLH and r-hFSH also achieved high levels of consensus. Significant agreement supported r-hLH supplementation and a tailored approach to luteal phase support. However, there were mixed opinions on the route of progesterone administration, with some experts expressing neutral or disagreeing views. Despite these differences, unanimous consensus was reached on markers of treatment success, particularly live birth rates, pregnancy rates, and embryo development, underscoring the importance of these outcomes in evaluating treatment efficacy.

Conclusion

This consensus provides a practical clinical perspective to a wide range of global professionals on the strategies employed during key phases of Assisted Reproductive Technology (ART) treatment. To further improve outcomes, incorporating additional clinical insights on ART approaches, alongside existing guidelines and policies, may offer valuable guidance for optimizing patient care.

Higher serum progesterone level has no negative impact on live birth rate in frozen embryo transfer

Optimal synchronisation between the endometrium and the embryo is key to the success of frozen embryo transfers (FET). It is achieved by administering different doses of exogenous oestrogen and progesterone (P4). The negative impact of low levels of P4 on FET has been reported, but there is a lack of knowledge about which levels are most appropriate. We aimed to evaluate whether high serum P4 levels measured on FET day affect the probability of having a baby at home. This retrospective cohort study includes 7546 FET cycles performed with hormone replacement therapy (HRT) for artificial endometrial preparation. Patients were divided into three groups according to P level on FET day (ng/mL): P4 < 20(n = 6623), P4 ≥ 20-40 (n = 770) and P > 40 (n = 146). Female age was per group P4 < 20 = 38.7 ± 3.1, P ≥ 20-40 = 39.0 ± 3.0, and P4 > 40 = 38.1 ± 2.9 years old (p = 0.53). The group with the highest progesterone levels found lower ongoing pregnancy rates without statistical significance (56.3 % (P4 < 20) vs 56.8 % (P4 ≥ 20-<40) vs 51.4 % (P4 > 40); p = 0.5). Miscarriage rate was also higher, although not significantly: 16.2 % (P4 < 20) vs 15.0 % (P4 ≥ 20-<40) vs 18.0 % (P4 > 40) (p = 0.6). These findings were explored with an adjusted analysis. A higher, but not significant, odds of miscarriage was observed when P4 > 40 ng/ml, aOR = 1.14 (0.75-1.74) (p = 0.55) whereas no such association was found with P4 ≥ 20-40 ng/ml (aOR = 0.92 (0.74-1.15) (p = 0.46)). The probability of livebirth is similar when the patient was P4 > 40 (aOR = 0.77 (0.51-1.15) (p = 0.20)) than when P4 ≥ 20-<40 (aOR = 0.94 (0.79-1.11) (p = 0.47). In conclusion, women with elevated serum P4 levels on the day of FET after HRT do not find their probability of live birth impaired.

Progesterone in frozen embryo transfer cycles: assays, circulating concentrations, metabolites, and molecular action

Programmed or medicated frozen embryo transfer cycles rely on exogenous progesterone (P) administration to prepare the endometrium for implantation and maintain pregnancy. Presently, the optimal route and dose of P replacement for frozen embryo transfer are not known. In addition, there is a paucity of data and insufficient understanding regarding the metabolism and actions of P in implantation and pregnancy maintenance. In the present review, we discuss how different P assay methodologies affect the determination of P thresholds for implantation and pregnancy maintenance. In addition, we discuss the importance of free P and its regulation in the endometrium and show the complexity of molecular signaling that is required for P-dependent endometrial receptivity. We concluded that future studies should focus on defining accurate circulating and endometrial P concentrations, both for total and free P, and how these concentrations correlate with endometrial receptivity and clinical outcomes.

Progesterone levels do not differ between patients with or without endometriosis/adenomyosis both in those who conceive after hormone replacement therapy-frozen embryo transfer cycles and those who do not

STUDY QUESTION

Do women with endometriosis who achieve a live birth (LB) after HRT-frozen embryo transfer (HRT-FET) have different progesterone levels on the day of transfer compared to unaffected women?

SUMMARY ANSWER

In women achieving a LB after HRT-FET, serum progesterone levels on the day of the transfer did not differ between patients with endometriosis and unaffected patients.

WHAT IS KNOWN ALREADY

In HRT-FET, several studies have highlighted the correlation between serum progesterone levels at the time of FET and LB rates. In the pathophysiology of endometriosis, progesterone resistance is typically described in the eutopic endometrium. This has led to the hypothesis that women with endometriosis may require higher progesterone levels to achieve a LB, especially in HRT-FET cycles without a corpus luteum.

STUDY DESIGN, SIZE, DURATION

We conducted an observational cohort study at the university-based reproductive medicine center of our institution, focusing on women who underwent a single autologous frozen blastocyst transfer after HRT using exogenous estradiol and micronized vaginal progesterone for endometrial preparation between January 2019 and December 2021. Women were included only once during the study period. Serum progesterone levels were measured on the morning of the FET by a single laboratory.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were divided into groups based on whether they had endometriosis or not and whether they achieved a LB. The diagnosis of endometriosis was based on published imaging criteria (transvaginal sonography/magnetic resonance imaging) and/or confirmed histology. The primary outcome was progesterone levels on the day of the HRT-FET leading to a LB in patients with endometriosis compared to unaffected women. Subgroup analyses were performed based on the presence of deep infiltrating endometriosis or adenomyosis.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1784 patients were included. The mean age of the women was 35.1 ± 4.1 (SD) years. Five hundred and sixty women had endometriosis, while 1224 did not. About 179/560 (32.0%) with endometriosis and 381/1224 (31.2%) without endometriosis achieved a LB. Among women who achieved a LB after HRT-FET, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (13.6 ± 4.3 ng/ml vs 13.2 ± 4.4 ng/ml, respectively; P = 0.302). In the subgroup of women with deep infiltrating endometriosis (n = 142) and adenomyosis (n = 100), the mean progesterone level was 13.1 ± 4.1 ng/ml and 12.6 ± 3.7 ng/ml, respectively, with no significant difference compared to endometriosis-free patients. After adjusting for BMI, parity, duration of infertility, tobacco use, and geographic origin, neither the presence of endometriosis (coefficient 0.38; 95% CI: -0.63 to 1.40; P = 0.457) nor the presence of adenomyosis (coefficient 0.97; 95% CI: -0.24 to 2.19; P = 0.114) was associated with the progesterone level on the day of HRT-FET. Among women who did not conceive, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (P = 0.709).

LIMITATIONS, REASONS FOR CAUTION

The primary limitation of our study is associated with its observational design. Extrapolating our results to other laboratories or different routes and/or dosages of administering progesterone also requires validation.

WIDER IMPLICATIONS OF THE FINDINGS

This study shows that patients diagnosed with endometriosis do not require higher progesterone levels on the day of a frozen blastocyst transfer to achieve a LB in hormonal replacement therapy cycles.

STUDY FUNDING/COMPETING INTEREST(S)

None declared.

TRIAL REGISTRATION NUMBER

N/A.

Progesterone concentrations on blastocyst transfer day in modified natural cycle frozen embryo transfer cycles

RESEARCH QUESTION

Are serum progesterone concentrations on the day of modified natural cycle (mNC) frozen blastocyst transfer (FET) without luteal phase support (LPS) associated with clinical pregnancy rate (CPR)?

DESIGN

Data were collected between January 2019 and October 2022 as a sub-study of an ongoing randomized controlled trial assessing pregnancy outcomes in mNC-FET. The sub-study included all women (n = 209) randomized to mNC-FET without LPS at the time of data extraction. Participants were aged 18-41 years, had regular menstrual cycles and underwent mNC-FET treatment with single-blastocyst transfer. Associations between the serum progesterone concentration on the day of blastocyst transfer and CPR, pregnancy rate and pregnancy loss rate (PLR) were examined between groups with low and higher progesterone concentrations using the 25th and 10th percentiles as cut-offs. Multivariate logistic regression analyses were performed to adjust for potential confounding factors.

RESULTS

Progesterone concentrations on the day of blastocyst transfer in mNC-FET without LPS ranged from 4.9 to 91.8 nmol/l, with the 25th and 10th percentiles at 29.0 nmol/l and 22.5 nmol/l, respectively. Serum progesterone concentrations did not differ between women with or without a clinical pregnancy (mean [SD] 38.5 [14.0] versus 36.8 [12.4] nmol/l; P = 0.350). Furthermore, the CPR, pregancy rate and PLR were similar in women with low or high progesterone concentrations when using the 25th or the 10th progesterone percentile as cut-off. Multivariate regression analyses showed no association between progesterone concentrations and CPR.

CONCLUSIONS

No association was found between progesterone concentration on the day of blastocyst transfer and pregnancy outcome in women undergoing mNC-FET without progesterone LPS.

Luteal phase support in assisted reproductive technology centers: Italian survey

BACKGROUND

In assisted reproductive cycles (ART), the fine balance of controlling corpus luteum function is severely disrupted. To challenge this iatrogenic deficiency, clinicians aim to provide exogenous support. Several reviews have investigated progesterone route of administration, dosage and timing.

METHODS

A survey about luteal phase support (LPS) after ovarian stimulation was conducted among doctors in charge in Italian II-III level ART centers.

RESULTS

With regards to the general approach to LPS, 87.9% doctors declare to diversify the approach; the reasons for diversifying (69.7%) were based on the type of cycle. For all the most important administration routes (vaginal, intramuscular, subcutaneous) it appears that in frozen cycles there is a shift towards higher dosages. The 90.9% of the centers use vaginal progesterone, and when a combined approach is required, in 72.7% of cases vaginal administration is combined with injective route of administration. When Italian doctors were asked about the beginning and duration of LPS, 96% of the centers start the day of the pickup or the day after, while 80% of the centers continue LPS until week 8-12. The rate of participation of the centers confirms the low perceived importance of LPS among Italian ART centers, while may be considered quite surprising the relatively higher percentage of centers that measures P level. Tailorization to women's needs is the new objective of LPS: self-administration, good tolerability are the main aspects for Italian centers.

CONCLUSIONS

In conclusion, results of Italian survey are consistent to results of main international surveys about LPS.

Different Dosages of Progesterone in Luteal Phase Support Reflect Varying Endometrial microRNA Expression in Frozen Embryo Transfer Cycles

Despite serum progesterone being a widely accepted method for luteal phase support during embryo transfer cycles, debates persist regarding the optimal strategy for guiding clinical decisions on progesterone dosages to maximize reproductive outcomes. This retrospective study explored the utility of microRNA (miRNA) biomarkers in guiding personalized progesterone dosage adjustments for frozen embryo transfer (FET) cycles in 22 in vitro fertilization (IVF) patients undergoing hormone replacement therapy. Utilizing MIRA, an miRNA-based endometrial receptivity test, we analyzed patients' miRNA expression profiles before and after progesterone dosage adjustments to determine suitable dosages and assess endometrial status. Despite patients receiving identical progesterone dosages, variations in miRNA profiles were observed in the initial cycle, and all patients presented a displaced window of implantation. Following dosage adjustments based on their miRNA profiles, 91% of patients successfully transitioned their endometrium towards the receptive stages. However, two patients continued to exhibit persistent displaced receptivity despite the adjustments. Given the evident variation in endometrial status and serum progesterone levels among individuals, analyzing miRNA expression profiles may address the challenge of inter-personal variation in serum progesterone levels, to deliver more personalized dosage adjustments and facilitate personalized luteal phase support in IVF.

Luteal phase support in assisted reproductive technology

Infertility affects one in six couples, with in vitro fertilization (IVF) offering many the chance of conception. Compared to the solitary oocyte produced during the natural menstrual cycle, the supraphysiological ovarian stimulation needed to produce multiple oocytes during IVF results in a dysfunctional luteal phase that can be insufficient to support implantation and maintain pregnancy. Consequently, hormonal supplementation with luteal phase support, principally exogenous progesterone, is used to optimize pregnancy rates; however, luteal phase support remains largely 'black-box' with insufficient clarity regarding the optimal timing, dosing, route and duration of treatment. Herein, we review the evidence on luteal phase support and highlight remaining uncertainties and future research directions. Specifically, we outline the physiological luteal phase, which is regulated by progesterone from the corpus luteum, and evaluate how it is altered by the supraphysiological ovarian stimulation used during IVF. Additionally, we describe the effects of the hormonal triggers used to mature oocytes on the degree of luteal phase support required. We explain the histological transformation of the endometrium during the luteal phase and evaluate markers of endometrial receptivity that attempt to identify the 'window of implantation'. We also cover progesterone receptor signalling, circulating progesterone levels associated with implantation, and the pharmacokinetics of available progesterone formulations to inform the design of luteal phase support regimens.

Association of serum progesterone levels on the transfer day with pregnancy outcomes in hormone replacement frozen-thawed cycles with oral dydrogesterone for strengthened luteal phase support

OBJECTIVE

To investigate the relationship between serum progesterone (P) levels on the day of blastocyst transfer and pregnancy outcomes in frozen-thawed embryo transfer (FET) cycles using hormone replacement therapy (HRT) with oral dydrogesterone for strengthened luteal phase support (LPS).

MATERIALS AND METHODS

This was a retrospective study including 1176 FET cycles. All patients received 40 mg of intramuscular (IM) P daily for endometrium transformation plus oral dydrogesterone 10 mg BID from transfer day for strengthened LPS. Pregnancy outcomes were compared between serum P levels on the transfer day ≥10 ng/ml and <10 ng/ml. Furthermore, cycles were divided into 10 groups by deciles of P and ongoing pregnancy rate (OPR) was calculated in each group. Analyses using deciles of serum P were completed to see if these could create further prognostic power.

RESULTS

No differences were observed in clinical pregnancy rates (CPRs), OPRs and live birth rates (LBRs) between serum P levels ≥10 ng/ml and <10 ng/ml. Patients with serum P levels <5.65 ng/ml (10th percentile) had a significantly lower OPR (48.31% vs. 58.98%, p = 0.03) and LBR (43.22% vs. 57.75%, p = 0.003) than the rest of the patients. Multivariate logistic regression analysis showed serum P levels on the transfer day were not associated with pregnancy outcomes.

CONCLUSION

Measuring serum P levels on the day of HRT-FET is of clinical importance. Lower serum P levels impact the success of HRT-FET cycles, suggesting that there may be a threshold below which it is difficult to improve pregnancy outcomes via oral dydrogesterone to strengthen LPS.

Low serum progesterone on day of transfer adversely impacts ongoing pregnancy rates in hormonally prepared single blastocyst frozen embryo transfer cycles

OBJECTIVE

To evaluate if serum progesterone (P) levels on the day of transfer influence ongoing pregnancy rate (OPR) in hormonally prepared single blastocyst frozen embryo transfer (FET) cycles?

STUDY DESIGN

Single center prospective cohort study conducted between June 2021 and August 2022 analyzed 217 single good quality blastocyst FET cycles hormonally prepared with oral estradiol valerate and micronized vaginal progesterone 400 mg twice daily.

RESULTS

Mean serum P on the day of embryo transfer (ET) was 9.76 ± 5.19 ng/ml. Receiver operator curve (ROC) showed a significant predictive value of serum P levels on the day of ET for OPR, with an area under curve (AUC) (95 %CI) = 0.58 (0.49-0.66). Optimal serum P threshold for OPR was 7.7 ng/ml (Sensitivity 76.8%, Specificity 43.7%). 35.9% patients had serum P below this threshold. BMI was significantly higher (26.8 ± 3.7 vs 25.6 ± 4.3; p = 0.048) in patients with serum P < 7.7 ng/ml vs ≥ 7.7 ng/ml. OPR was significantly lower (24.4% vs 45.3%; p = 0.002) and clinical miscarriage rates significantly higher (37.9% vs 19.2%; p = 0.042) if serum P < 7.72 ng/ml vs ≥ 7.7 ng/ml.

CONCLUSION

This study found that serum P level on the day of transfer in hormonally prepared FET cycles was a significant predictor of OPR.

The Effect of Different Luteal Phase Support Applications on Clinical Pregnancy Outcomes in Frozen-Thawed Embryo Transfer

Purpose

During the frozen-thawed embryo transfer (FET) method, controlled ovarian hyperstimulation is used. At the same time, progesterone support is given for luteal phase support. In this study, we investigated the effects of various luteal phase support agents administered orally, intramuscularly (IM), and vaginally during FET on pregnancy rates.

Methods

The files of 166 patients between the ages of 21 and 44 in the Assisted Reproductive Techniques Center of Acıbadem Mehmet Ali Aydınlar University Atakent Hospital were analyzed retrospectively between 2016 and 2022. The patients' FSH, LH, E2, P4, AMH, and TSH levels were measured. The GnRH antagonist protocol was initiated on the 2nd or 3rd day of menstruation. Three types of progesterone agents were used in females with PCOS. Three different methods were applied: 50 mg/ml of IM progesterone daily, 90 mg of progesterone gel 2∗1 vaginally, and dydrogesterone acetate tb. orally 3∗1. FET was performed on women who received 21 days of treatment by thawing 5th-day embryos. B-hCG was performed on the 12th day after the transfer, and evaluations were made. The study results were evaluated as follows: for the whole study group, for those <30 years of age, for those 30-35 years of age, and for those >35 years of age.

Results

A total of 164 patients, 57 females using vaginal progesterone gel, 30 females using oral progesterone tablet, and 77 females using IM progesterone, who met the inclusion criteria, were included in the study. The pregnancy outcomes of IM progesterone application were statistically significantly higher in the entire study group and the >35 age group when compared to the vaginal progesterone gel application. It was found that the pregnancy outcomes of IM progesterone application increased statistically significantly in the <30 age group when compared to outcomes in the other groups, using vaginal progesterone gel and oral progesterone tb.

Conclusions

We found that IM progesterone application was more effective than vaginal progesterone gel application for luteal phase support. Many randomized controlled, especially live birth rate studies, are required before results can more closely approximate those for the general population.

Serum progesterone level in luteal phase improves pregnancy rate in fresh cycles with blastocyst embryo transfer

OBJECTIVE

To assess the association between serum level of progesterone during stimulation and in the luteal phase with pregnancy rate in a cohort of patients undergoing in vitro fertilization and embryo transfer (IVF-ET) on day 5.

METHODS

Retrospective Cohort Study. Patients: 62 infertile women, aged 24-42 years, undergoing ART at our center from May 2019 to May 2021. Progesterone was evaluated during ovarian stimulation on Day 2, Day 6, and Day 8 of stimulation, day of trigger (P4dhCG), and on the day of blastocyst transfer with 5 days of progesterone supplementation (P4d5+). We also calculated the difference of P4d5+ with P4dhCG. (∆P4). Then we divided the patients into two groups based on progesterone serum levels at P4d5+; <10ng/ml (Group A), ≥10ng/ml (Group B). The Student's t-test was performed for continuous variables; Mann-Whitney's Test and Spearman's Test were used where appropriate for categorical variables. p<0.05 was considered statistically significant.

RESULTS

There were positive correlations between βhCG positive with P4d5+ (p<0.001; Rho 0.770) and ∆P4 (p<0.001; Rho 0.703). The pregnancy rate doubled when the serum progesterone level was ≥10ng/ml on the fifth day of progesterone supplementation compared with P4<10ng/ml (44% vs. 21%, respectively).

CONCLUSIONS

The pregnancy rate was positively correlated with the serum P4 level on the fifth day of progesterone supplementation and with the difference between the serum progesterone level in the Dd5+ / dhCG. A higher pregnancy rate was observed when serum progesterone level on the fifth day of progesterone supplementation was ≥10ng/ml.

Effectiveness of progesterone rescue in women presenting low circulating progesterone levels around the day of embryo transfer: a systematic review and meta-analysis

IMPORTANCE

Over the last decade, frozen embryo transfer (FET) has been increasingly used in contemporary fertility units. Despite the rapid increase in FET, there is still insufficient evidence to recommend an optimized protocol for endometrial preparation especially in patients with lower progesterone (P4) levels. Previous studies have concluded that P4 levels <10 ng/mL are associated with poorer pregnancy outcomes than those reported with high levels of circulating P4.

OBJECTIVE

To identify whether rescue P4 dosing in patients with low P4 can salvage adverse outcomes associated with low P4 levels, resulting in outcomes comparable to patients with adequate progesterone.

DATA SOURCES

The study was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines and prospectively registered under the PROSPERO database (CRD42022357125). Six databases (Embase, MEDLINE, APA PsycInfo, Global Health, HMIC Health Management Information Consortium, and Google Scholar) and 2 additional sources were searched from inception to August 29, 2022.

STUDY SELECTION AND SYNTHESIS

Prospective and retrospective cohort studies, reporting the association between rescue progesterone and one or more pregnancy outcomes, were included. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS), while the quality of evidence by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. Summative and subgroup data as well as heterogeneity were generated by the Cochrane platform RevMan (V. 5.4).

MAIN OUTCOME MEASURE(S)

To compare ongoing pregnancy rate as primary outcome and clinical pregnancy rate, miscarriage rate, and live birth rate as secondary outcomes between patients with low (<10 ng/mL) receiving rescue progesterone vs. those with adequate levels of P4 (≥10 ng/mL).

RESULT(S)

Overall, 7 observational studies were included in the analysis, with a total of 5927 patients of median age 34 (interquartile range [IQR]: 31.55, 37.13). Overall, patient group comparison, namely those with low P4 that received a rescue dose and those with adequate P4 levels, did not yield significant differences for either the primary or secondary outcomes. For ongoing clinical pregnancy, patients with low P4 receiving the rescue dose vs. those with adequate P4 levels was odds ratio (OR) 0.98 (95% CI: 0.78, 1.24; P = .86, I²: 41%), whereas for miscarriage events, OR was 0.98 (95% CI: 0.81, 1.17; P = .80, I²: 0). Equally, for clinical pregnancy, OR was 0.91 (95% CI: 0.78, 1.06; P = .24; I²: 33%), and for live birth, OR was 0.92 (95% CI: 0.77, 1.09; P = .33; I²: 43%). Subgroup analysis on the basis or rescue administration route successfully explained summative heterogeneity.

CONCLUSION(S)

Rescue P4 dosing in patients with low P4 results in ongoing pregnancy rate, clinical pregnancy and live birth rates were comparable to those of patients with adequate P4 levels. However, robust randomized controlled trials assessing rescue treatment in women with low P4 are needed to confirm these findings. Rescue P4 in patients with low circulating P4 around embryo transfer day may result in reproductive outcomes comparable to those with adequate P4 levels.

STUDY REGISTRATION

CRD42022357125 (PROSPERO).

Impact of different endometrial preparation protocols before frozen embryo transfer on pregnancy outcomes: a review

The use of frozen embryo transfer cycles has exponentially increased in the last few years. Optimization of endometrial preparation protocols before frozen embryo transfer is mandatory to further improve pregnancy outcomes. This review will focus on the existing literature with regard to the different available endometrial preparation protocols and their impact on pregnancy outcomes. More specifically, we will focus on programmed, natural, and stimulated frozen embryo transfer cycles. The studies performed on this topic are generally of low quality, and only a few well-performed randomized controlled trials have been published. To date, no strong evidence is available to support the use of 1 preparation method over another in terms of pregnancy outcomes. However, robust data have shown a clearly protective effect of natural frozen embryo transfer cycles against long-term obstetric complications, mainly hypertensive disorders of pregnancy and large for gestational age infants. The introduction of individualized luteal phase support in different endometrial preparation protocols is actually gaining a lot of attention and requires further investigation.

Treatment outcomes of blastocysts thaw cycles, comparing the presence and absence of a corpus luteum: a systematic review and meta-analysis

PURPOSE

This study aims to review the literature and perform a meta-analysis to determine if the presence of a corpus luteum has an impact on treatment outcomes in thaw cycles, where blastocyst embryos are transferred.

METHOD

PUBMED, EMBASE, CENTRAL and CINAHL were searched for papers published between January 2017 and 27 July 2020. Additional articles were selected from the reference list of the results and previous reviews. Three reviewers independently reviewed and extracted data. The meta-analysis was conducted though RevMan V.5.4.1. Studies were quality assessed with the Cochrane risk of bias tool and the Newcastle-Ottawa Scale.

RESULTS

Nine publications were included for data extraction and subsequent meta-analysis. Two studies were randomised controlled trials, and seven were cohort studies. Subgroup analysis of the different study designs was performed. While the rates of positive human chorionic gonadotropin results (relative risk, RR 1.0, 95% CI 0.95 to 1.05) and clinical pregnancies (RR 1.06, 95% CI 0.96 to 1.18) were comparable between the two groups, the rates of live births were higher in thaw cycles with a corpus luteum (RR 1.14, 95% CI 1.06 to 1.22). Analysis of pregnancy losses demonstrated that both biochemical pregnancy (early miscarriage) (RR 0.71, 95% CI 0.62 to 0.82) and miscarriages (RR 0.72, 95% CI 0.62 to 0.83) were increased in cycles without a corpus luteum.

CONCLUSION

Where clinically appropriate, the use of cycle types that have a functional corpus luteum should be favoured. There were several limitations to this study, including the quality of studies and the inherent bias of retrospective cohort studies. Further, high-quality research, particularly randomised controlled trials with blastocysts embryos, is required to further explore these findings.

PROSPERO REGISTRATION NUMBER

CRD42020209583.

Natural cycles achieve better pregnancy outcomes than artificial cycles in non-PCOS women undergoing vitrified single-blastocyst transfer: a retrospective cohort study of 6840 cycles

PURPOSE

To identify the optimal method for endometrial preparation in vitrified single-blastocyst transfer (VSBT) cycles.

METHODS

This was a retrospective cohort study for non-PCOS patients who underwent VSBT cycles from March 2015 to November 2019 in an academic reproductive medical center. A total of 6840 VSBT cycles were enrolled and classified into two groups according to different endometrial preparation methods.

RESULTS

The non-PCOS patients who underwent VSBT showed a significantly higher clinical pregnancy rate (61.96% vs 56.85%, p < 0.001) and live birth rate (49.09% vs 39.86%, p < 0.001), as well as a statistically lower early miscarriage rate (12.02% vs 18.08%, p < 0.001) in the natural cycle (NC) group compared with the artificial cycle (AC) group. Multivariable analysis further confirmed that NC was associated with an increased likelihood of clinical pregnancy (adjusted odds ratio (aOR) 0.852, 95% confidence interval (CI) 0.765-0.949, p = 0.004) and live birth (aOR 0.746, 95% CI 0.669-0.832, p < 0 .001), but decreased early miscarriage occurrence (aOR 1.447, 95% CI 1.215-1.724, p < 0.001) compared to AC.

CONCLUSIONS

Our study demonstrated that non-PCOS patients could benefit from NC in vitrified blastocyst transfer. Increased clinical pregnancy rate and decreased early miscarriage rate led to a significantly higher live birth rate in NC patients compared with AC with our present protocol.

Low serum progesterone affects live birth rate in cryopreserved blastocyst transfer cycles using hormone replacement therapy

RESEARCH QUESTION

Does serum progesterone concentration on the day of vitrified-warmed embryo transfer affect live birth rate (LBR) with hormonal replacement therapy (HRT) cycles?

DESIGN

Observational cohort study of patients (n = 915) undergoing single autologous vitrified-warmed blastocyst transfer under HRT using vaginal micronized progesterone. Women were included once, between January 2019 and March 2020. Serum progesterone concentration was measured by a single laboratory on the morning of embryo transfer. The primary end point was LBR. Univariate and multivariate logistic regression models were used for statistical analyses.

RESULTS

Median (25th-75th percentile) serum progesterone concentration on the day of embryo transfer was 12.5 ng/ml (9.8-15.3). The LBR was 31.5% (288/915) in the overall population. No significant differences were found in implantation rates (40.7% versus 44.9%); LBR was significantly lower in women with a progesterone concentration ≤25th percentile (≤9.8 ng/ml) (26.1% versus 33.2%, P = 0.045) versus women with a progesterone concentration >25th percentile. This correlated with a significantly higher early miscarriage rate (35.9% versus 21.6%, P = 0.005). After adjusting for potential confounding factors in multivariate analysis, low serum progesterone levels (≤9.8 ng/ml) remained significantly associated with lower LBR (OR 0.68 95% CI 0.48 to 0.97).

CONCLUSION

A minimum serum progesterone concentration is needed to optimize reproductive outcomes in HRT cycles with single autologous vitrified-warmed blastocyst transfer. Whether modifications of progesterone administration routes, dosage, or both, can improve pregnancy rates needs further study so that treatment of patients undergoing HRT cycles can be further individualized.

Progesterone and estrogen levels are associated with live birth rates following artificial cycle frozen embryo transfers

PURPOSE

Does an association exist between serum progesterone and estradiol levels and live birth rates in artificial cycle frozen embryo transfer (AC-FET)?

METHODS

Retrospective cohort study was based on prospectively collected data at a university-affiliated fertility center. Included were all cycles using an artificial endometrial preparation with estradiol hemihydrate (Estrofem, 2 mg/8 h) and vaginal progesterone (Endometrin 100 mg/8 h), autologous oocytes, and cleavage stage embryo transfers. Serum progesterone and estradiol levels were measured 14 days after FET. A total of 921 cycles in 568 patients from to December 2010 to June 2019 were investigated. Live birth was the primary outcome measure.

RESULTS

Significant association was found between live birth and progesterone as well as estradiol levels (progesterone 14.65 vs 11.62 ng/ml, p = 0.001; estradiol 355.12 vs 287.67 pg/ml, p = 0.001). A significant difference in live birth rate was found below and above the median progesterone level (10.9 ng/ml, p = 0.007). Lower estradiol level was significantly associated with lower live birth rate (< 188.2 pg/ml 8.3%, > 263.1 pg/ml 16%, p = 0.02).

CONCLUSIONS

Serum progesterone and estradiol levels impact live birth rate in AC-FET.

Serum luteal phase progesterone in women undergoing frozen embryo transfer in assisted conception: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between luteal serum progesterone levels and frozen embryo transfer (FET) outcomes.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women undergoing FET.

INTERVENTION(S)

We conducted electronic searches of MEDLINE, PubMed, CINAHL, EMBASE, the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and grey literature (not widely available) from inception to March 2021 to identify cohort studies in which the serum luteal progesterone level was measured around the time of FET.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy or live birth rate, clinical pregnancy rate, and miscarriage rate.

RESULT(S)

Among the studies analyzing serum progesterone level thresholds <10 ng/mL, a higher serum progesterone level was associated with increased rates of ongoing pregnancy or live birth (relative risk [RR] 1.47, 95% confidence interval [CI] 1.28 to 1.70), higher chance of clinical pregnancy (RR 1.31, 95% CI 1.16 to 1.49), and lower risk of miscarriage (RR 0.62, 95% CI 0.50 to 0.77) in cycles using exclusively vaginal progesterone and blastocyst embryos. There was uncertainty about whether progesterone thresholds ≥10 ng/mL were associated with FET outcomes in sensitivity analyses including all studies, owing to high interstudy heterogeneity and wide CIs.

CONCLUSION(S)

Our findings indicate that there may be a minimum clinically important luteal serum concentration of progesterone required to ensure an optimal endocrine milieu during embryo implantation and early pregnancy after FET treatment. Future clinical trials are required to assess whether administering higher-dose luteal phase support improves outcomes in women with a low serum progesterone level at the time of FET.

PROSPERO NUMBER

CRD42019157071.

The effect of weight and body mass index on serum progesterone values and live birth rate in cryopreserved in vitro fertilization cycles

Objective

To determine if weight or body mass index (BMI) affects the serum progesterone level at the time of the pregnancy test in cryopreserved blastocyst transfer cycles and to determine if those serum progesterone levels affect live births.

Design

Retrospective cohort study.

Setting

US academic medical center.

Patient(s)

Six hundred thirty-three patients undergoing their first cryopreserved embryo transfer cycle.

Intervention(s)

None.

Main Outcome Measure(s)

The primary outcome was the serum progesterone level on the day of the pregnancy test by patient weight and BMI. Our secondary analysis assessed the serum progesterone effect on live birth rate (LBR) in a clinic where progesterone supplementation was increased if the progesterone level was <15 ng/mL on the day of the pregnancy test.

Results(s)

There was a strong negative correlation between serum progesterone level and both BMI and weight, with BMI accounting for 27% and weight accounting for 29% of the variance in progesterone level. Serum progesterone level on the day of the pregnancy test was <15 ng/mL in 3% of women weighing <68 kg compared with 29% of women weighing ≥90.7 kg. Among women weighing ≥90.7 kg, live birth occurred in 47% whose serum progesterone level was <15 ng/mL on the day of the pregnancy test compared with 49% in those with serum progesterone level of 15–19 ng/mL and 44% in those with serum progesterone level of ≥20 ng/mL.

Conclusion(s)

Body weight was a significant factor in serum progesterone level at the time of the pregnancy test, with nearly 30% of patients weighing ≥90.7 kg having serum progesterone level of <15 ng/mL, a value associated with lower LBRs in prior studies. However, we found no effect of low progesterone levels on LBR after cryopreserved embryo transfer cycles in a clinic where progesterone dosing was increased if serum progesterone levels were <15 ng/mL.

Impact of low serum progesterone levels on the day of embryo transfer on pregnancy outcome: a prospective cohort study in artificial cycles with vaginal progesterone

STUDY QUESTION

Is there a serum progesterone (P) threshold on the day of embryo transfer (ET) in artificial endometrium preparation cycles below which the chances of ongoing pregnancy are reduced?

SUMMARY ANSWER

Serum P levels <8.8 ng/ml on the day of ET lower ongoing pregnancy rate (OPR) in both own or donated oocyte cycles.

WHAT IS KNOWN ALREADY

We previously found that serum P levels <9.2 ng/ml on the day of ET significantly decrease OPR in a sample of 211 oocyte donation recipients. Here, we assessed whether these results are applicable to all infertile patients under an artificial endometrial preparation cycle, regardless of the oocyte origin.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study was performed between September 2017 and November 2018 and enrolled 1205 patients scheduled for ET after an artificial endometrial preparation cycle with estradiol valerate and micronized vaginal P (MVP, 400 mg twice daily).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients ≤50 years old with a triple-layer endometrium ≥6.5 mm underwent transfer of one or two blastocysts. A total of 1150 patients treated with own oocytes without preimplantation genetic testing for aneuploidies (PGT-A) (n = 184), own oocytes with PGT-A (n = 308) or donated oocytes (n = 658) were analyzed. The primary endpoint was the OPR beyond pregnancy week 12 based on serum P levels measured immediately before ET.

MAIN RESULTS AND THE ROLE OF CHANCE

Women with serum P levels <8.8 ng/ml (30th percentile) had a significantly lower OPR (36.6% vs 54.4%) and live birth rate (35.5% vs 52.0%) than the rest of the patients. Multivariate logistic regression showed that serum P < 8.8 ng/ml was an independent factor influencing OPR in the overall population and in the three treatment groups. A significant negative correlation was observed between serum P levels and BMI, weight and time between the last P dose and blood tests and a positive correlation was found with age, height and number of days on HRT. Multivariate logistic regression showed that only body weight was an independent factor for presenting serum P levels <8.8 ng/ml. Obstetrical and perinatal outcomes did not differ in patients with ongoing pregnancy regardless of serum P levels being above/below 8.8 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

Only women with MVP were included. Extrapolation to other P administration forms needs to be validated.

WIDER IMPLICATIONS OF THE FINDINGS

This study identified the threshold of serum P as 8.8 ng/ml on the day of ET for artificial endometrial preparation cycles necessary to optimize outcomes, in cycles with own or donated oocytes. One-third of patients receiving MVP show inadequate levels of serum P that, in turn, impact the success of the ART cycle. Monitoring P levels in the mid-luteal phase is recommended when using MVP to adjust the doses according to the needs of the patient.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

NCT03272412.

Individualised luteal phase support in artificially prepared frozen embryo transfer cycles based on serum progesterone levels: a prospective cohort study

STUDY QUESTION

Does an individualised luteal phase support (iLPS), according to serum progesterone (P4) level the day prior to euploid frozen embryo transfer (FET), improve pregnancy outcomes when started on the day previous to embryo transfer?

SUMMARY ANSWER

Patients with low serum P4 the day prior to euploid FET can benefit from the addition of daily subcutaneous P4 injections (Psc), when started the day prior to FET, and achieve similar reproductive outcomes compared to those with initial adequate P4 levels.

WHAT IS KNOWN ALREADY

The ratio between FET/IVF has spectacularly increased in the last years mainly thanks to the pursuit of an ovarian hyperstimulation syndrome free clinic and the development of preimplantation genetic testing (PGT). There is currently a big concern regarding the endometrial preparation for FET, especially in relation to serum P4 levels around the time of embryo transfer. Several studies have described impaired pregnancy outcomes in those patients with low P4 levels around the time of FET, considering 10 ng/ml as one of the most accepted reference values. To date, no prospective study has been designed to compare the reproductive outcomes between patients with adequate P4 the day previous to euploid FET and those with low, but restored P4 levels on the transfer day after iLPS through daily Psc started on the day previous to FET.

STUDY DESIGN, SIZE, DURATION

A prospective observational study was conducted at a university-affiliated fertility centre between November 2018 and January 2020 in patients undergoing PGT for aneuploidies (PGT-A) IVF cycles and a subsequent FET under hormone replacement treatment (HRT). A total of 574 cycles (453 patients) were analysed: 348 cycles (leading to 342 euploid FET) with adequate P4 on the day previous to FET, and 226 cycles (leading to 220 euploid FET) under iLPS after low P4 on the previous day to FET, but restored P4 levels on the transfer day.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall we included 574 HRT FET cycles (453 patients). Standard HRT was used for endometrial preparation. P4 levels were measured the day previous to euploid FET. P4 > 10.6 ng/ml was considered as adequate and euploid FET was performed on the following day (FET Group 1). P4 < 10.6 ng/ml was considered as low, iLPS was added in the form of daily Psc injections, and a new P4 analysis was performed on the following day. FET was only performed on the same day when a restored P4 > 10.6 ng/ml was achieved (98.2% of cases) (FET Group 2).

MAIN RESULTS AND THE ROLE OF CHANCE

Patient's demographics and cycle parameters were comparable between both euploid FET groups (FET Group 1 and FET Group 2) in terms of age, weight, oestradiol and P4 levels and number of embryos transferred. No statistically significant differences were found in terms of clinical pregnancy rate (56.4% vs 59.1%: rate difference (RD) -2.7%, 95% CI [-11.4; 6.0]), ongoing pregnancy rate (49.4% vs 53.6%: RD -4.2%, 95% CI [-13.1; 4.7]) or live birth rate (49.1% vs 52.3%: RD -3.2%, 95% CI [-12; 5.7]). No significant differences were also found according to miscarriage rate (12.4% vs 9.2%: RD 3.2%, 95% CI [-4.3; 10.7]).

LIMITATIONS, REASONS FOR CAUTION

Only iLPS through daily Psc was evaluated. The time for Psc injection was not stated and no serum P4 determinations were performed once the pregnancy was achieved.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides information regarding an 'opportunity window' for improved ongoing pregnancy rates and miscarriage rates through a daily Psc injection in cases of inadequate P4 levels the day previous to FET (P4 < 10.6 ng/ml) and restored values the day of FET (P4 > 10.6 ng/ml). Only euploid FET under HRT were considered, avoiding one of the main reasons of miscarriage and implantation failure and overcoming confounding factors such as female age, embryo quality or ovarian stimulation protocols.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was received. B.C. reports personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, IBSA and Gedeon Richter outside the submitted work. N.P. reports grants and personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, Theramex and Besins International and personal fees from IBSA and Gedeon Richter outside the submitted work. The remaining authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

NCT03740568.

Strengthened luteal phase support for patients with low serum progesterone on the day of frozen embryo transfer in artificial endometrial preparation cycles: a large-sample retrospective trial

BACKGROUND

Low serum progesterone on the day of frozen embryo transfer (FET) is associated with diminished pregnancy rates in artificial endometrium preparation cycles, but there is no consensus on whether strengthened luteal phase support (LPS) benefits patients with low progesterone on the FET day in artificial cycles. This single-centre, large-sample retrospective trial was designed to investigate the contribution of strengthened LPS to pregnancy outcomes for groups with low progesterone levels on the FET day in artificial endometrium preparation cycles.

METHODS

Women who had undergone the first artificial endometrium preparation cycle after a freeze-all protocol in our clinic from 2016 to 2018 were classified into two groups depending on their serum progesterone levels on the FET day. Routine LPS was administered to group B (P ≥ 10.0 ng/ml on the FET day, n = 1261), and strengthened LPS (routine LPS+ im P 40 mg daily) was administered to group A (P < 10.0 ng/ml on the FET day, n = 1295). The primary endpoint was the live birth rate, and the secondary endpoints were clinical pregnancy, miscarriage and neonatal outcomes.

RESULTS

The results showed that the clinical pregnancy rate was significantly lower in group A than in group B (48.4% vs 53.2%, adjusted risk ratio (aRR) 0.81, 95% confidence interval (CI) 0.68, 0.96), whereas miscarriage rates were similar between the two groups (16.0% vs 14.7%, aRR 1.09, 95% CI 0.77, 1.54). The live birth rate was slightly lower in group A than in group B (39.5% vs 43.3%, aRR 0.84, 95% CI 0.70, 1.0). Birthweights and other neonatal outcomes were similar between the two groups (P > 0.05).

CONCLUSIONS

The results indicated that the serum progesterone level on the FET day was one of the risk factors predicting the chances of pregnancy in artificial endometrium preparation cycles, and strengthened LPS in patients with low progesterone on the FET day might help to provide a reasonable pregnancy outcome in artificial cycles, although further prospective evidence is needed to confirm this possibility.