Cumulative live birth rates according to the number of oocytes retrieved following the "freeze-all" strategy

Fertility preservation in women with endometriosis: Oocyte cryopreservation and other techniques

In recent years, advancements in cryopreservation techniques for oocytes, embryos, and ovarian tissue have enabled offering fertility preservation (FP) options to women with endometriosis. It is recommended to always conduct specialized counselling on FP, especially before considering surgical interventions for endometriosis. The decision regarding the methods of FP, the timing, and to which women affected by endometriosis these techniques should be offered are still subjects of discussion. However, several studies suggest that it can be proposed before surgical interventions for endometriosis, particularly if the patient is undergoing mono or bilateral endometrioma surgery. The most recommended technique is ovarian stimulation, followed by oocyte cryopreservation. Nevertheless, the literature contains various studies describing FP through embryo cryopreservation or the retrieval and cryopreservation of ovarian tissue.

Comparative analysis of pregnancy outcomes in preimplantation genetic testing for aneuploidy and conventional in vitro fertilization and embryo transfer: a stratified examination on the basis of the quantity of oocytes and blastocysts from a multicenter randomized controlled trial

OBJECTIVE

To investigate variations in pregnancy outcomes between preimplantation genetic testing for aneuploidy (PGT-A) and conventional in vitro fertilization and embryo transfer (IVF-ET) treatment across distinct groups categorized by oocyte and blastocyst counts. Because the live birth rate (LBR) of assisted reproductive technology treatment is influenced by the number of oocytes and blastocysts retrieved. Our previous study indicated comparable cumulative LBRs (CLBRs) between conventional IVF-ET and PGT-A.

DESIGN

A post hoc exploratory secondary analysis of data from a multicenter randomized controlled trial compared the CLBRs between conventional IVF-ET and PGT-A.

SETTING

Academic fertility centers.

SUBJECTS

A total of 1,212 infertile women with a good prognosis for a live birth after PGT-A or conventional IVF-ET were included.

INTERVENTION

Women underwent PGT-A or conventional IVF-ET.

MAIN OUTCOME MEASURE(S)

Cumulative LBR, cumulative clinical pregnancy loss (CPL) rate, and good birth outcome.

RESULT(S)

In the study, all participants were divided into 4 groups on the basis of quartiles of the number of oocytes retrieved, or blastocysts. There was an interaction between whether to perform PGT-A and the oocyte numbers category on cumulative CPL and biochemical pregnancy loss. Chi-square analysis revealed that the PGT-A group showed a lower cumulative frequency of CPL compared with the IVF-ET group (PGT-A vs. IVF-ET: 5.9% vs. 13.7%; relative risk = 0.430; 95% confidence interval, 0.243-0.763) when the number of oocytes retrieved was <15. Although there was no interaction on CLBR when the retrieved oocyte count ranged from 19-23 (19≤ oocytes <23) the PGT-A group exhibited a lower CLBR than the conventional IVF-ET group (PGT-A vs IVF-ET: 75.6% vs 87.1%; relative risk = 0.868; 95% confidence interval, 0.774-0.973), and the average body weight of newborns from the PGT-A group was approximately 142 g lower than that of the conventional IVF-ET group (PGT-A vs. IVF-ET: 3,334 ± 479 g vs. 3,476 ± 473 g). However, no statistically significant difference in the CLBR was observed between the PGT-A and IVF-ET groups in the other oocyte or blastocyst groups.

CONCLUSION

When the number of retrieved eggs was <15, the PGT-A group exhibited a lower cumulative CPL rate but no higher CLBR than the conventional IVF-ET group.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03118141.

The cumulative live birth rates of 18 593 women with progestin-primed ovarian stimulation-related protocols and frozen-thawed transfer cycles

STUDY QUESTION

What are the odds of achieving pregnancy when adopting progestin-primed ovarian stimulation (PPOS)-related protocols combined with repetitive frozen-thawed transfer (FET) cycles in patients with different clinical characteristics?

SUMMARY ANSWER

The cumulative live birth rates (CLBRs) of women undergoing different PPOS-related protocols can be significantly and consistently enhanced within six FET cycles when the female age is <40 years (or even <45 years) and when >5 oocytes are retrieved, regardless of antral follicle count (AFC).

WHAT IS KNOWN ALREADY

There have been numerous studies on the live birth rate of the first FET cycle in patients with PPOS-related protocols. These studies have focused mainly on comparing pregnancy outcomes with those of other stimulation protocols. However, owing to the unique features of the PPOS-related strategy, such as its flexible timing of oocyte retrieval and repeated transfer of frozen embryos, studies using the CLBR as an overall indicator of success and investigating which types of patients would benefit from this protocol are lacking.

STUDY DESIGN SIZE DURATION

This retrospective cohort study included 18 593 women who underwent PPOS-related protocols (dydrogesterone + hMG, medroxyprogesterone acetate + hMG, micronized progesterone + hMG treatment, and luteal-phase ovarian stimulation protocol) from 1 March 2011 to 31 September 2022 in our centre.

PARTICIPANTS/MATERIALS SETTING METHODS

The population was categorized by female age, number of oocytes retrieved, and AFC in the analysis of CLBR within six FET cycles. The age groups (Groups 1-5, respectively) were <30, 30-34, 35-39, 40-44, and ≥45 years. The number of oocytes retrieved was grouped as 1-5, 6-10, 11-15, 16-20, and >20. AFC was grouped as <5, 5-10, 11-15, and >15. The Kaplan-Meier analysis (optimistic method), which hypothesized that patients who did not continue treatment had the same chance of achieving a live birth as those who continued, and the competing risk method (conservative method) which hypothesized they had no chance of achieving a live birth, were applied. In further analyses, the Cox model and Fine-Gray model were adopted: the former corresponds to the optimistic scenario, and the latter corresponds to the pessimistic scenario.

MAIN RESULTS AND THE ROLE OF CHANCE

CLBR had a declining trend with female age over six FET cycles (Groups 1-5, respectively: optimistic: 96.9%, 96.6%, 91.4%, 67.3%, and 11.7%; conservative: 87.3%, 85.0%, 74.0%, 41.3%, and 7.5%), requiring more FET cycles to achieve a success rate of at least 50% (Groups 1-5, respectively: optimistic: 2, 2, 2, 4, and >6 cycles; conservative: 2, 2, 2, >,6 and >6 cycles). CLBR showed an increasing trend with the number of oocytes retrieved (Groups 1-5, respectively: optimistic: 93.8%, 94.3%, 95.8%, 96.0%, and 95.6%; conservative: 66.2%, 78.3%, 85.6%, 88.9%, and 91.0%). All groups needed the same number of FET cycles to achieve a success rate of at least 50% (Groups 1-5, respectively: optimistic: 2, 2, 2, 2, and 2 cycles; conservative: 2, 2, 2, 2, and 2 cycles). Furthermore, the CLBR within six FET cycles had an increasing trend with AFC number (Groups 1-4, respectively: optimistic: 89.2%, 94.8%, 95.9%, and 96.3%; conservative: 67.4%, 78.2%, 83.9%, and 88.1%), with all four groups achieving a success rate of at least 50% by the second FET cycle.

LIMITATIONS REASONS FOR CAUTION

The current research is limited by its retrospective design and single-centre nature, which may restrict the generalizability of our findings.

WIDER IMPLICATIONS OF THE FINDINGS

This work describes two models (the Kaplan-Meier analysis and the competing risk method) to evaluate the clinical outcome of patients using PPOS-related protocols, which are especially useful for patients of advanced age or those with diminished ovarian reserve. Our findings encourage patients below 45 years old, especially younger than 40 years, and patients with lower AFCs and fewer retrieved oocytes to try this new protocol. Moreover, this study demonstrates the degree of improvement in the CLBR within six FET cycles for patients with different clinical characteristics, providing a valuable point of reference to determine whether to continue ART after a transfer failure.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by grants from the National Natural Science Foundation of China (82071603 to L.W., 82001502 to Y.L.). There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Oocyte degeneration in a cohort adversely affects clinical outcomes in conventional IVF cycles: a propensity score matching study

Background

Oocyte degeneration was mostly described in intracytoplasmic sperm injection (ICSI) cycles; there is no report showing the relationship between oocyte degeneration and clinical outcomes in conventional in vitro fertilization (IVF) cycles. This retrospective study using the propensity score (PS) matching method aimed to explore whether the presence of oocyte degeneration in conventional IVF cycles would affect the sibling embryo development potential and clinical outcomes.

Methods

Patients with at least one oocyte degenerated after short-term insemination and stripping were defined as the degeneration (DEG) group, while patients with no oocyte degenerated were defined as the non-degeneration (NONDEG) group. The PS matching method was used to control for potential confounding factors, and a multivariate logistic regression analysis was made to evaluate whether the presence of oocyte degeneration would affect the cumulative live birth rate (CLBR).

Results

After PS matching, basic characteristics were similar between the two groups, oocyte yield was significantly higher in the DEG group than the NON-DEG group (P < 0.05), mature oocyte number, 2 pronuclear (2PN) embryo number, 2PN embryo clearage rate, "slow" embryo number, "accelerated" embryo number, rate of cycles with total day 3 embryo extended culture, number of frozen embryo transfer (FET) cycles, transferred embryo stage, transferred embryo number, and live birth rate in fresh embryo transfer cycles were all similar between the two groups (P > 0.05), but the 2PN fertilization rate, available embryo number, high-quality embryo number, "normal" embryo number, frozen embryo number, blastocyst formation rate, and no available embryo cycle rate were all significantly lower in the DEG group than the NON-DEG group (P < 0.05). The cumulative live birth rate was also significantly lower in the DEG group than in the NON-DEG group (70.2% vs. 74.0%, P = 0.0019). Multivariate logistic regression analysis further demonstrated that the presence of oocyte degeneration in conventional IVF cycles adversely affects the CLBR both before (OR = 0.83, 95% CI: 0.75-0.92) and after (OR = 0.82, 95% CI: 0.72-0.93) PS matching.

Conclusion

Our findings together revealed that the presence of oocyte degeneration in a cohort of oocytes may adversely affect subsequent embryo development potential and clinical outcomes in conventional IVF cycles.

Association between the number of oocytes and cumulative live birth rate: A systematic review

The available literature is controversial regarding the association between the number of oocytes retrieved and the cumulative live birth rate (CLBR). Although some authors report a continuous increase in the CLBR with the number of oocytes retrieved, others have found a plateau. A systematic review was conducted, including all eligible studies published until June 2022, to determine the optimal number of oocytes retrieved to maximize the CLBR. We found a positive association between the number of oocytes and the CLBR. However, this association varies according to patients' age. While in patients younger than 35 years, little benefit is derived from increasing the number of oocytes above 25-30, in patients older than 35 years, the number of oocytes seems to improve the CLBR until the extreme of reproductive age is reached. In women aged 44 years or older, the CLBR will be consistently low, independent of the number of oocytes retrieved.

When to Transfer Embryos if There Is Only 1 or 2?

The latest reports suggest that it is better to transfer embryos to the uterus on day five of preimplantation development compared to other days of development, but it is not clear if this stands when there are only one-two embryos obtained in the cycle. Therefore, to address this issue, we performed a retrospective study of such cycles. Our study included all of the stimulated IVF/ICSI cycles performed at our institution in the period between 1 January 2004 and 31 December 2018 in which one-two embryos were obtained in the IVF/ICSI cycle and met our inclusion criteria, and we compared the data between day three and day five embryo transfer (ET). The analysis revealed that the day three ET group of patients was significantly older (p < 0.001), were administered a significantly higher dose of gonadotrophins (p = 0.015), and retrieved a lower mean number of aspirated oocytes per cycle (p < 0.001) and lower mean number of embryos (p < 0.001). The birth rate per ET was significantly higher in the day five ET group (p = 0.045) and further analysis indicated that this could be due the trend observed in a group of patients under 36 years old, while in older patients there was no such difference. To conclude, our retrospective study indicates that it might be better to perform ET on day five instead of day three when there are only one-two embryos obtained in the cycle, but probably only when patients are under 36 years old.

Does the outcome of fresh embryo transfer affect the outcome of subsequent thawed embryo transfers from sibling oocytes in patients that utilized all their embryos?

The association between fresh embryo transfer (ET) outcome and the subsequent frozen-thawed (FET) cycles that follow is not clear, mainly because of incomplete embryo cohort utilization. The aim of this study was to determine if the outcome of a fresh ET affects the frozen cumulative clinical pregnancy (CP) and live birth (LB) rates resulting from the utilization of all surplus embryos from sibling oocytes. Outcome measures were the FET cumulative CP and LB rates. Multivariate logistic regression was performed for the frozen cumulative CP rate and adjusted for age, the number of oocytes, fresh ET outcome and other confounders. A total of 1313 cycles met the inclusion criteria. The FET cumulative CP and LB rates were not affected by the outcome of the fresh ET. The FET cumulative CP rate increased with the number of oocytes collected regardless of whether a pregnancy was achieved in the fresh cycle or not. In multivariate analysis, age (OR = 0.96, 95% CI 0.94-0.98), protocol (OR = 0.13, 95% CI 0.03-0.57) and the number of oocytes (OR = 1.05, 95% CI 1.02-1.07) were associated with the frozen cumulative CP rate. It is concluded that fresh ET does not impact the outcome of the vitrified-thawed embryos from the same oocyte cohort.

Pro: Fresh versus frozen embryo transfer. Is frozen embryo transfer the future?

Embryo cryopreservation has been an integral part of ART for close to 40 years and vitrification has boosted overall ART efficacy and safety. Recently, there has been a vivid scientific discussion on whether elective cryopreservation of all embryos (freeze-all) should be pursued for most patients, with a fresh embryo transfer taking place only in selected cases. In terms of efficacy, the available evidence suggests that the freeze-all strategy leads to higher live birth rates after the first embryo transfer compared to the conventional strategy in high responders, while there is no difference in normal responders. There is no evidence to suggest that the freeze-all strategy is inferior to the conventional strategy of fresh transfer when comparing cumulative live birth rates using data from all available randomized controlled trials. The incidence of ovarian hyperstimulation syndrome is significantly reduced in the freeze-all policy. However, regarding obstetric complications and neonatal outcomes, the evidence suggests that each strategy is associated with certain risks and, therefore, there is no approach that could be unequivocally accepted as safer. Similarly, limited evidence does not support the notion that patients would be universally against freeze-all owing to the inevitable delay in pregnancy achievement. Finally, the cost-effectiveness of freeze-all is likely to vary in different settings and there have been studies supporting that this policy can be, under certain conditions, cost-effective. Adoption of the freeze-all policy can also allow for more flexible treatment strategies that have the potential to increase efficacy, reduce cost and make treatment easier for patients and clinics. Importantly, freeze-all does not require the use of any experimental technologies, further training of personnel or the costly acquisition of new equipment. For these reasons, transitioning to the freeze-all policy for most patients appears to be the next logical step in ART.

Algorithm-based individualization methodology of the starting gonadotropin dose in IVF/ICSI and the freeze-all strategy prevent OHSS equally in normal responders: a systematic review and network meta-analysis of the evidence

PURPOSE

Ovarian hyperstimulation syndrome (OHSS) represents a rare but dangerous condition associated with controlled ovarian stimulation (COS) in IVF/ICSI. Over the last decades, many strategies have been introduced into clinical practice with the objective of preventing this potentially life-threatening condition. Among these, the freeze-all policy has gained great popularity, thanks to improvements in vitrification. Nevertheless, not all clinics have adequate skills in vitrification procedures and patients may be dissatisfied with a longer time to pregnancy.

METHODS

This study is a systematic review and network meta-analysis of randomized controlled trials comparing different strategies of ovarian stimulation in IVF/ICSI cycles (freeze-all policy, algorithm-based individualization of the starting dose, experience-based individualization of the starting dose, standard dose) in terms of reduction of OHSS, in normal responders.

RESULTS

The results indicate that only the algorithm-based individualization of the starting gonadotropin dose reduces OHSS similarly to the freeze-all strategy.

CONCLUSION

Albeit in the era of the freeze-all policy, the personalization of the starting gonadotropin dose obtained by the use of algorithms should be pursued as a valid and safe option for IVF.

Optimal individualization of patient-oriented ovarian stimulation in Japanese assisted reproductive technology clinics, a review for unique setting with advanced-age patients

Ovarian stimulation is a key issue in assisted reproductive technology (ART) treatment. ART practice in Japan is unique with various types of ovarian stimulation protocols, which may contribute to lower pregnancy rates compared to other countries. This review aims to clarify optimal individualized ovarian stimulation for improving the pregnancy rate per one oocyte retrieval cycle in Japan. We performed a literature review to describe ovarian stimulation, classification of infertile women depending on ovarian reserve and response, and Japanese ART data and discussed optimal conventional and mild ovarian stimulation protocols in Japan. According to Japanese ART registry data, the live birth rate of 30-35-year-old women was 32%-37% per ET cycle; therefore, four to five embryos are calculatedly needed when aiming a cumulative live birth rate of ≥80%. Mild stimulation aimed at collecting 5-10 oocytes can be alternative choice as an optimal ovarian stimulation protocol in young women. In 40-year-old women, the live birth rate is 18.8%, resulting in eight or more embryos as necessary. Conventional stimulation must be required in women with advanced age. In poor responders, however, mild stimulation may be sufficient for maximumly extracting their ovarian function. In Japan, mild ovarian stimulation can be selected in patients with a good prognosis and poor responders; however, conventional ovarian stimulation is necessary for women in advanced age.

Ethical considerations of preconception and prenatal gene modification in the embryo and fetus

The National Academies of Sciences and Medicine 2020 consensus statement advocates the reinstatement of research in preconception heritable human genome editing (HHGE), despite the ethical concerns that have been voiced about interventions in the germline, and outlines criteria for its eventual clinical application to address monogenic disorders. However, the statement does not give adequate consideration to alternative technologies. Importantly, it omits comparison to fetal gene therapy (FGT), which involves gene modification applied prenatally to the developing fetus and which is better researched and less ethically contentious. While both technologies are applicable to the same monogenic diseases causing significant prenatal or early childhood morbidity, the benefits and risks of HHGE are distinct from FGT though there are important overlaps. FGT has the current advantage of a wealth of robust preclinical data, while HHGE is nascent technology and its feasibility for specific diseases still requires scientific proof. The ethical concerns surrounding each are unique and deserving of further discussion, as there are compelling arguments supporting research and eventual clinical translation of both technologies. In this Opinion, we consider HHGE and FGT through technical and ethical lenses, applying common ethical principles to provide a sense of their feasibility and acceptability. Currently, FGT is in a more advanced position for clinical translation and may be less ethically contentious than HHGE, so it deserves to be considered as an alternative therapy in further discussions on HHGE implementation.

Does the freeze-all strategy improve the cumulative live birth rate and the time to become pregnant in IVF cycles?

PURPOSE

The freeze-all strategy is widely used for ovarian hyperstimulation syndrome (OHSS) prevention. Indeed, it increases live birth rates among high responders and prevents preterm birth and small for gestational age. Why should not we extend it to all?

METHODS

A retrospective and monocentric study was conducted between January 2008 and January 2018 comparing the cumulative live birth rates (CLBR) between patients having undergone FAS and a control group using fresh embryo transfer (FET) and having at least one frozen embryo available. Analyses were made for the entire cohort (population 1) and for different subgroups according to confounding factors selected by a logistic regression (population 3), and to the BELRAP (Belgian Register for Assisted Procreation) criteria (population 2).

RESULTS

2216 patients were divided into two groups: Freeze all (FA), 233 patients and control (C), 1983 patients. The CLBR was 50.2% vs 58.1% P = 0.021 for population 1 and 53.2% vs 63.3% P = 0.023 for population 2, including 124 cases and 1241 controls. The CLBR stayed in favour of the C group: 70.1% vs 55.9% P = 0.03 even when confounding variables were excluded (FA and C group, respectively, 109 and 770 patients). The median time to become pregnant was equally in favour of the C group with a median of 5 days against 61 days.

CONCLUSION

CLBR is significantly lower in the FA group compared to the C group with a longer time to become pregnant. Nevertheless, the CLBR in the FA group remains superior to that observed in previous studies.

Reintroducing serum FSH measurement during ovarian stimulation for ART

RESEARCH QUESTION

What is the impact of systemic FSH concentrations during ovarian stimulation for IVF/intracytoplasmic sperm injection on systemic progesterone concentrations in the late follicular phase?

DESIGN

Post-hoc analysis of a previously performed randomized controlled trial (RCT) performed between November 2017 and February 2020 in a tertiary IVF centre. The RCT included patients with infertility undergoing ovarian stimulation in a gonadotrophin-releasing hormone (GnRH) antagonist protocol. The GnRH antagonist was administered at 08:00 h and recombinant FSH at 20:00 h. Ultrasound and blood tests were performed 3-5 h after the GnRH antagonist.

RESULTS

The subgroup analysis comprised 105 patients. Systemic FSH concentrations increased from Day 2/3 until initiation of GnRH antagonist and remained constant until the day of trigger (DoT). The total group was split according to the median FSH DoT concentration (12.95 IU/l; Group A <12.95 IU/l; Group B ≥12.95 IU/l). Significant differences, with the higher concentrations in Group B, were found for: systemic FSH concentration on Day 2/3 (P = 0.04), total gonadotrophin dosage (P = 0.03), progesterone on DoT (P = 0.001) and progesterone per follicle (P = 0.004). In the total group, systemic DoT FSH concentration was statistically significantly positively correlated with the DoT progesterone concentration and the ratio of progesterone per follicle (ρ = 0.37 and 0.38, respectively, both P < 0.001). No significant correlations were seen between the systemic DoT FSH concentration and the number of retrieved oocytes.

CONCLUSION

While ovarian response seems to be independent from the systemic FSH concentrations on the DoT, high concentrations of circulatory FSH augment the production of progesterone.

Dual trigger protocol is an effective in vitro fertilization strategy in both normal and high responders without compromising pregnancy outcomes in fresh cycles

Objective

To study the birth rates of normal vs. high responders after dual trigger of final oocyte maturation with gonadotropin-releasing hormone (GnRH) agonist and human chorionic gonadotropin in fresh in vitro fertilization (IVF) cycles in which ovarian stimulation was achieved by a flexible GnRH antagonist protocol.

Design

Retrospective cohort study.

Setting

University hospital.

Patient(s)

In women <35 years of age, 290 fresh IVF cycles using the dual trigger protocol with day 5 embryo transfers from January 2013 to July 2018 were included. Cycles excluded were those with preimplantation genetic testing, gestational carriers, donor oocytes, and fertility preservation.

Intervention(s)

IVF with dual trigger.

Main Outcome Measure(s)

Clinical pregnancy rate, live birth rate.

Result(s)

Comparing normal responders, defined as <30 oocytes retrieved, and high responders, defined as ≥30 oocytes retrieved, the clinical pregnancy rates (67.0% vs. 69.3%, respectively) and live birth rates (60.5% vs. 60.0%, respectively) were not significantly different. No cases of ovarian hyperstimulation syndrome were reported in either group.

Conclusion(s)

Ovarian stimulation by a flexible GnRH antagonist protocol followed by dual trigger yields comparable outcomes between normal and high responders in fresh IVF cycles.

Is a freeze-all policy the optimal solution to circumvent the effect of late follicular elevated progesterone? A multicentric matched-control retrospective study analysing cumulative live birth rate in 942 non-elective freeze-all cycles

STUDY QUESTION

Is late follicular elevated progesterone (LFEP) in the fresh cycle hindering cumulative live birth rates (CLBRs) when a freeze only strategy is applied?

SUMMARY ANSWER

LFEP in the fresh cycle does not affect the CLBR of the frozen transfers in a freeze only approach, nor the embryo freezing rate.

WHAT IS KNOWN ALREADY

Ovarian stimulation promotes the production of progesterone (P) which has been demonstrated to have a deleterious effect on IVF outcomes. While there is robust evidence that this elevation produces impaired endometrial receptivity, the impact on embryo quality remains a matter of debate. In particular, previous studies have shown that LFEP is associated with a hindered CLBR. However, most clinical insight on the effect of progesterone on embryo quality in terms of CLBRs have focused on embryo transfers performed after the fresh transfer, thus excluding the first embryo of the cohort. To be really informative on the possible detrimental effects of LFEP, evidence should be derived from freeze-all cycles where no fresh embryo transfer is performed in the presence of progesterone elevation, and the entire cohort of embryos is cryopreserved.

STUDY DESIGN, SIZE, DURATION

This was a matched case-control, multicentre (three centres), retrospective analysis including all GnRH antagonist ICSI cycles in which a freeze all (FA) policy of embryos on day 3/5/6 of embryonic development was applied between 2012 and 2018. A total of 942 patients (471 cases with elevated P and 471 matched controls with normal P values) were included in the analysis. Each patient was included only once.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The sample was divided according to the following P levels on the day of ovulation triggering: <1.50 ng/ml and ≥1.50 ng/ml. The matching of the controls was performed according to age (±1 year) and number of oocytes retrieved (±10%). The main outcome was CLBR defined as a live-born delivery after 24 weeks of gestation.

MAIN RESULTS AND THE ROLE OF CHANCE

The baseline characteristics of the two groups were similar. Estradiol levels on the day of trigger were significantly higher in the elevated P group. There was no significant difference in terms of fertilisation rate between the two groups. The elevated P group had significantly more cleavage stage frozen embryos compared to the normal P group while the total number of cryopreserved blastocyst stage embryos was the same. The CLBR did not differ between the two study groups (29.3% and 28.2% in the normal versus LFEP respectively, P = 0.773), also following confounder adjustment using multivariable GEE regression analysis (accounting for age at oocyte retrieval, total dose of FSH, progesterone levels on the day of ovulation trigger, day of freezing, at least one top-quality embryo transferred and number of previous IVF cycles, as the independent variables).

LIMITATIONS, REASONS FOR CAUTION

This is a multicentre observational study based on a retrospective data analysis. Better extrapolation of the results could be validated by performing a prospective analysis.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study demonstrating that LFEP in the fresh cycle does not hinder CLBR of the subsequent frozen cycles in a FA approach. Thus, a FA strategy circumvents the issue of elevated P in the late follicular phase.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was received for this study. Throughout the study period and manuscript preparation, authors were supported by departmental funds from: Centre for Reproductive Medicine, Brussels, Belgium; Infertility Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Centro Scienze Natalità, San Raffaele Scientific Institute, Milan, Italy; and IVI-RMA, Lisbon, Portugal. E.S. has competing interests with Ferring, Merck-Serono, Theramex and Gedeon-Richter outside the submitted work. E.P. reports grants from Ferring, grants and personal fees from Merck-Serono, grants and personal fees from MSD and grants from IBSA outside the submitted work. All the other authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Comparison of Cumulative Live Birth Rates Between GnRH-A and PPOS in Low-Prognosis Patients According to POSEIDON Criteria: A Cohort Study

OBJECTIVE

To compare the cumulative live birth rate (CLBR) of a gonadotropin-releasing hormone (GnRH) antagonist regimen and a progestin-primed ovarian stimulation (PPOS) regimen in low-prognosis patients according to POSEIDON criteria.

DESIGN

Single-center, retrospective, observational study.

SETTING

Henan Provincial People's Hospital, Zhengzhou, China.

PATIENTS

Women aged ≤40 years, with a body mass index <25 kg/m², who underwent in vitro fertilization (IVF) or intracytoplasmic sperm microinjection (ICSI) and met POSEIDON low-prognosis criteria.

INTERVENTION

GnRH or PPOS regimen with IVF or ICSI.

MAIN OUTCOME MEASURE

CLBR per oocyte retrieval cycle.

RESULTS

Per oocyte retrieval cycle, CLBR was significantly higher with GnRH antagonist versus PPOS (35.3% vs 25.2%; P<0.001). In multivariable logistic regression analysis, CLBR per oocyte retrieval cycle was significantly lower with PPOS versus GnRH antagonist before (OR 0.62 [95% confidence intervals (CI): 0.46, 0.82; P=0.009]) and after (OR 0.66 [95% CI: 0.47, 0.93; P=0.0172]) adjustment for age, body mass index, infertility type, infertility duration, baseline follicle stimulating hormone, anti-Müllerian hormone (AMH), antral follicle count (AFC), and insemination method. CLBR was numerically higher with the GnRH antagonist regimen than with PPOS, across all of the POSEIDON groups, and was significantly higher in patients aged ≥35 years with poor ovarian reserve [AFC <5, AMH <1.2 ng/mL] (unadjusted, P=0.0108; adjusted, P=0.0243).

CONCLUSION

In this single-center, retrospective, cohort study, patients had a higher CLBR with a GnRH antagonist versus PPOS regimen, regardless of other attributes.