Beyond the monitoring: simplifying frozen embryo transfer cycles through patient selection.

Do the length of follicular phase estradiol exposure and the total length of the follicular phase affect pregnancy and live birth outcomes in natural frozen embryo transfer (FET) cycles? An estradiol level >100 pg/ml for ≤4 days including the LH surge day is associated with worse pregnancy and live birth outcomes; however, the total length of the follicular phase is not associated with pregnancy and live birth outcomes. An estradiol level that increases above 100 pg/ml and continues to increase is indicative of the selection and development of a dominant follicle. In programmed FET cycles, a limited duration of follicular phase estradiol of <9 days results in worse pregnancy rates, but a prolonged exposure to follicular phase estradiol for up to 4 weeks does not affect pregnancy outcomes. It is unknown how follicular phase characteristics affect pregnancy outcomes in natural FET cycles. This retrospective cohort study included infertile patients in an academic hospital setting who underwent their first natural frozen autologous Day-5 embryo transfer cycle in our IVF clinic between 01 January 2013 and 31 December 2018. Donor oocyte and gestational carrier cycles were excluded. The primary outcomes of this study were pregnancy and live birth rates. Patients were stratified into two groups based on the cohorts' median number of days from the estradiol level of >100 pg/ml before the LH surge: Group 1 (≤4 days; n = 1052 patients) and Group 2 (>4 days; n = 839 patients). Additionally, patients were stratified into two groups based on the cohorts' median cycle day of LH surge: Group 1 (follicular length ≤15 days; n = 1287 patients) and Group 2 (follicular length >15 days; n = 1071 patients). A subgroup analysis of preimplantation genetic testing for aneuploidies (PGT-A) embryo transfer cycles was performed. Logistic regression analysis, adjusted a priori for patient age, number of embryos transferred, and use of PGT-A, was used to estimate the odds ratio (OR) with a 95% CI. In the length of elevated estradiol analysis, the pregnancy rate per embryo transfer was statistically significantly lower in patients with an elevated estradiol to surge of ≤4 days (65.6%) compared to patients with an elevated estradiol to surge of >4 days (70.9%; OR 1.30 (95% CI 1.06-1.58)). The live birth rate per embryo transfer was also statistically significantly lower in patients with an elevated estradiol to surge of ≤4 days (46.6%) compared to patients with an elevated estradiol to surge of >4 days (52.0%; OR 1.23 (95% CI 1.02-1.48)). In the follicular phase length analysis, the pregnancy rate per embryo transfer was similar between patients with a follicular length of ≤15 days (65.4%) and patients with a follicular length of >15 days (69.0%; OR 1.12 (95% CI 0.94-1.33)): the live birth rate was also similar between groups (45.5% vs 51.5%, respectively; OR 1.14 (95% CI 0.97-1.35)). In all analyses, once a pregnancy was achieved, the length of the follicular phase or the length of elevated oestradiol >100 pg/ml no longer affected the pregnancy outcomes. The retrospective design of this study is subject to possible selection bias in regard to which patients at our clinic were recommended to undergo a natural FET compared to a fresh embryo transfer or programmed FET. To decrease the heterogeneity of our study population, we only included patients who had blastocyst embryo transfers; therefore, it is unknown whether similar results would be observed in patients with cleavage-stage embryo transfers. The retrospective nature of the study design did not allow randomized to a specific ovarian stimulation or ovulation trigger protocol. However, all patients were managed with the standardized protocols at a single center, which strengthens the external validity of our results when compared to a study that only evaluates one specific stimulation protocol. Our observations provide cycle-level characteristics that can be applied during a natural FET cycle to help optimize embryo transfer success rates. Physicians should consider the parameter of number of days that oestradiol is >100 pg/ml prior to the LH surge when determining whether to proceed with embryo transfer in a natural cycle. This cycle-specific characteristic may also help to provide an explanation for some failed transfer cycles. Importantly, our findings should not be used to determine whether to recommend a natural or a programmed FET cycle for a patient, but rather, to identify natural FET cycles that are not optimal to proceed with embryo transfer. No financial support, funding, or services were obtained for this study. The authors do not report any potential conflicts of interest. N/A.

Background and Aims: Low serum progesterone (P) levels on day of embryo transfer (ET) and luteal phase have been associated with poorer pregnancy outcome. This study aimed to know if serum estradiol (E2) and P levels during mid and late luteal phase are related with ongoing pregnancy. Method: The serum E2 and P levels from mid luteal phase (5 days after ET) to the day of the [Formula: see text]-hCG check (11 days after ET) in both fresh and frozen embryo transfer (FET) cycles was investigated between January 2019 and December 2021. Eligible patients were reproductive aged women with a normal uterus. Single blastocyst transfer cycles were included. Estradiol valerate (2 mg/bid) was started from day 3 of cycle as hormone replacement and vaginal micronized P (400 mg/bid) was started 5 days before ET in all FET cycles. The 2-degree polynomial fitted data were analysed and logistic linear model and ROC analysis were performed to assess E2 and P4 polynomial coefficients as a predictive test for ongoing pregnancy. Results: A total of 388 patients were included. The overall pregnancy rate was 43.8% and 31.3% for FET and fresh ET, respectively. On day 5 post ET, the serum P levels correlated significantly with ongoing pregnancy and live birth rates, especially in FET cycles. The ROC curve showed that there is a significant day 5 post ET predictive value of serum P4/E2 levels for pregnancy rate, being the AUC (95% CI) = 0.596 (0.539–0.653) for the combination of both fresh and FET cycles; and 0.611 (0.548–0.674) for FET cycles, with best cut-off values of 0.079 and 0.077, respectively. Conclusion: Serum P levels in mid and late luteal phase days are associated with pregnancy outcome both in fresh and frozen ET cycles. Ongoing pregnancies can be predicted using the day 5 post ET serum P4/E2 levels.

Study question does uterine contractions differ between aromatase inhibitor stimulated (AIS) or artificial hormone treatment (AHT) Frozen Embryo transfer (FET) cycles Summary answer uterine contraction activity did not show any difference between artificial hormone treatment and aromatase inhibitor stimulated FET cycles What is known already FET cycles are prepared by different protocols. aromatase inhibitor stimulated (AIS) or artificial hormone treatment (AHT) protocols are two common protocols among others. These protocols have different cycle dynamics and might differ in pregnancy rates and different effects on perinatal outcomes. Although embryo related factors are most important for implantation endometrial receptivity and therefore uterine contractions might have a role in implantation. English literature provides scarce data on uterine contractions and pregnancy outcomes. Presence of prominent contractions were related to poor pregnancy outcomes in some studies whereas other few studies failed to show any effect in this sense Study design, size, duration this study is an observational cohort study of successive frozen embryo transfer (FET) cycles of eligible patients between 1st of july 2023 to 31th of October 2023 in a tertiary university hospital in vitro fertilization clinic with ultrasonographic video recordings at transfer day. During study period of four months, 147 out of 265 consecutive FET cycles were included in this study and study is approved by local ethical committee of the affiliated university (KA23/388). Participants/materials, setting, methods Total study group was composed of 99 artificial hormone treatment cycles and 48 aromatase inhibitor stimulated FET cycles after exclusion of patients with uterine congenital malformations, uterine fibroids,adenomyosis patients and patient with previous uterine surgery. Implantation rates, pregnancy rates and clinical pregnancy rates were recorded. Transvaginal ultrasonographic sagittal uterine video image recordings were obtained at transfer day one hour before embryo transfer. Recordings were reviewed by two researchers and uterine contractions were documented by agreement. Main results and the role of chance This is the first study comparing different FET cycles and uterine contraction activities. Patient characteristics were similar between two groups. Artificial hormone treatment and aromatase inhibitor stimulated cycle groups showed similar endometrial thicknesses (11.47±1.92 and 11.24±1.02, respectively p = 0.42) and top quality embryo transfer rates (22.6 % and 26.8% p = 0.82). Although AIH group showed a statistically insignificant advantage, clinical and ongoing pregnancy rates were similar between protocols (supplementary data). Uterine peristaltic activity was not statistically different between aromataze inhibitor stimulated and artificial hormone treatment FET cycle (1.54±1.75 versus 1.63±2.15 p = 0.81 recpectively). Furthermore uterine persistalsizm were similar in pregnant and non-pregnant patients /1.52±2.07 vs 1.72±1.93 p = 0.57). However as far as Aromatase inhibitor stimulated FET cycles were considered; pregnant patients had less uterine peristaltic activity when compared ton non-pregnant patient (45.7% and 15.4%, respectively p = 0.054 ) although this difference was at the border of statistical significance. Limitations, reasons for caution This is an observational study of relatively short duration with limited number of patients. Our study in AIS cycles have a tendency to fewer contractions in cycles ended up in pregnancy. Larger series of FET cycles might prove differences in uterine contraction frequencies and pregnancy outcomes in AIS FET cycles. Wider implications of the findings Our study supported new information on uterine contractility in different FET cycles protocols. Further large scale studies might provide new insights to uterine factor and its role in implantation as far as uterine contraactions are concerned. Trial registration number (KA23/388) local ethic committee approval

Endometrin as luteal phase support in assisted reproduction

Is there an association between the length of in vitro culture, mode of ART and the initial endogenous hCG rise, in cycles with a foetal heartbeat after single embryo transfer (ET) and implantation? Both the length of in vitro culture and the mode of ART have an impact on the initial endogenous rise in hCG in singleton pregnancies. Different factors have been identified to alter the kinetics of hCG in pregnancies. Current studies show conflicting results regarding the kinetics of hCG after different types of ART (fresh vs frozen ET (FET)), the inclusion or not of preimplantation genetic testing (PGT), and the length of time in in vitro culture. This was a multicentre cohort study, using prospectively collected data derived from 4938 women (5524 treatment cycles) undergoing IUI (cycles, n = 608) or ART (cycles, n = 4916) treatments, resulting a in singleton ongoing pregnancy verified by first-trimester ultrasound scan. Data were collected from the Danish Medical Data Centre, used by the three participating Danish public fertility clinics at Copenhagen University hospitals: Herlev Hospital, Hvidovre Hospital, and Rigshospitalet, from January 2014 to December 2021. The fresh ET cycles included cleavage-stage (2 or 3 days in vitro) and blastocyst (5 days in vitro) transfers. FET cycles included cleavage-stage (3 days in vitro before cryopreservation) or blastocyst (5 or 6 days in vitro before cryopreservation) transfers. The IUI cycles represented no time in vitro. To attain a comparable interval for serum-hCG (s-hCG), the ovulation induction time was identical: 35-37 h before oocyte retrieval or IUI. The conception day was considered as: the insemination day for pregnancies conceived after IUI, the oocyte retrieval day for fresh ET, or the transfer day minus 3 or 5 as appropriate for FET of Day 3 or 5 embryos. Multiple linear regression analysis was used, including days post-conception for the hCG measurement as a covariate, and was adjusted for the women's age, the cause of infertility, and the centre. For FET, a sensitivity analysis was used to adjust for endometrial preparation. The study totally includes 5524 cycles: 2395 FET cycles, 2521 fresh ET cycles, and 608 IUI cycles. Regarding the length of in vitro culture, with IUI as reference (for no time in in vitro culture), we found a significantly lower s-hCG in pregnancies achieved after fresh ET (cleavage-stage ET or blastocyst transfer). S-hCG was 18% (95% CI: 13-23%, P < 0.001) lower after fresh cleavage-stage ET, and 23% (95% CI: 18-28%, P < 0.001) lower after fresh blastocyst transfer compared to IUI. In FET cycles, s-hCG was significantly higher after blastocyst transfers compared to cleavage-stage FET, respectively, 26% (95% CI: 13-40%, P < 0.001) higher when cryopreserved on in vitro Day 5, and 14% (95% CI: 2-26%, P = 0.02) higher when cryopreserved on in vitro Day 6 as compared to Day 3. Regarding the ART treatment type, s-hCG after FET blastocyst transfer (Day 5 blastocysts) cycles was significantly higher, 33% (95% CI: 27-45%, P < 0.001), compared to fresh ET (Day 5 blastocyst), while there was no difference between cleavage-stage FET (Days 2 + 3) and fresh ET (Days 2 + 3). S-hCG was 12% (95% CI: 4-19%, 0.005) lower in PGT FET (Day 5 blastocysts) cycles as compared to FET cycles without PGT (Day 5 blastocysts). The retrospective design is a limitation which introduces the risk of possible bias and confounders such as embryo score, parity, and ovarian stimulation. This study elucidates how practices in medically assisted reproduction treatment are associated with the hCG kinetics, underlining a potential impact of in vitro culture length and mode of ART on the very early embryo development and implantation. The study provides clinicians knowledge that the type of ART used may be relevant to take into account when evaluating s-hCG for the prognosis of the pregnancy. No funding was received for this study. AP has received consulting fees, research grants, or honoraria from the following companies: Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos, Merck A/S, and Organon. AZ has received grants and honoraria from Gedeon Richter. NLF has received grants from Gedeon Richter, Merck A/S, and Cryos. MLG has received honoraria fees or research grants from Gedeon Richter, Merck A/S, and Cooper Surgical. CB has received honoraria from Merck A/S. MB has received research grants and honoraria from IBSA. MPR, KM, and PVS all report no conflicts of interest. The study was registered and approved by the Danish Protection Agency, Capital Region, Denmark (Journal-nr.: 21019857). No approval was required from the regional ethics committee according to Danish law.

Study question Is the live birth rate (LBR) in euploid frozen embryo transfer (FET) cycles affected by the endometrial thickness (EMT)? Summary answer A significantly higher LBR was observed in patients with an endometrial thickness of at least 7.5mm (46.24% vs. 54.63%) What is known already Parameters assessing the endometrium prior planning a FET include endometrial thickness, pattern and blood flow. The impact of the endometrial thickness on ART outcomes is controversial, with conflicting results published. A recent meta-analysis evaluated whether EMT could predict pregnancy outcomes and suggested that lower EMT was associated with lower incidence of clinical pregnancy rate (CPR), implantation rate (IR) and LBR. Due to heterogeneity of parameters evaluated between different publications, where embryos with unknown ploidy status were transferred, in conjunction with variability of stimulation protocols and the number of embryos transferred, the real effect of the EMT was difficult to infer. Study design, size, duration This was a two-center retrospective observational study including a total of 1522 euploid FET cycles between March 2017 and March 2020 at ART Fertility Clinics Muscat, Oman and Abu Dhabi, UAE. Participants/materials, setting, methods Trophectoderm biopsies were analyzed with Next Generation Sequencing (NGS). Vitrification/warming of blastocysts was performed using Cryotop method (Kitazato). EMT was measured by vaginal ultrasound prior initiating the progesterone administration (± 1 day) and LBR was recorded. Multivariate analysis was performed between LB outcomes and median EMT while controlling for confounding factors. Main results and the role of chance A total of 1522 FET cycles were analyzed: 975 single embryo transfer (SET) and 547 double embryo transfer (DET). The mean age of the patients was 33.38 years with a mean BMI of 27.1 kg/m2. FET were performed in EMT ranging from 3 to 15 mm and 50.52% resulted in a live birth. Though potentially all ranges of EMT were associated with LB, the median EMT in patients with LB was significantly higher than the median EMT of patients without LB (7.6mm vs. 7.4mm; p &amp;lt; 0.001). The dataset was stratified into two groups based on the median EMT (7.5mm): &amp;lt; 7.5mm (n = 744 cycles) and ≥ 7.5mm (n = 778 cycles). A significantly higher live birth rate was observed in ≥ 7.5mm group (46.24% vs. 54.63%. p = 0.0012). In multivariate analysis, EMT, FET endometrial preparation protocol, and number of embryos transferred were the main parameters influencing the chance to achieve LB: OR 1.10 [1.01–1.19], p &amp;lt; 0.015 for the EMT; OR 1.84 [1.47–2.30], p &amp;lt; 0.0001 for Natural Cycle protocol and OR 1.55 [1.25–1.93], p &amp;lt; 0.0001 for DET. Intercept 0.18 [0.07–0.44] p &amp;lt; 0.0002. Female age did not reach significance: OR 1.02 [1.00–1.04], p = 0.056. Limitations, reasons for caution Besides the retrospective nature of the study, the inter-observer variability in EMT assessment between different physicians is a limitation. The physician and embryologist performing the embryo transfer could not been standardized due to the multicenter design of the study. Wider implications of the findings: The EMT in FET may influence the LBR and should be considered as an important factor for the success of embryo transfer cycles. Whether these results can be extrapolated to fresh embryo transfer and to blastocysts with unknown ploidy status, needs further investigation. Trial registration number Not applicable

Does a frozen embryo transfer ameliorate the effect of elevated progesterone seen in fresh transfer cycles?

Study question What is the benefit of adding frozen embryo transfer (FET) cycles to ICSI clinical outcomes in male factor infertility? Summary answer FET carried out on spare embryos that reached blastocyst stage remarkably contributed to additional clinical pregnancies in ICSI cycles for male factor infertility. What is known already Current trends in reproductive medicine lean toward full-preimplantation development and eventually to PGT-A to select a single euploid embryo for transfer. The utilization of this approach, while beneficial in most couples, is not ideal for male factor infertility due to the tendency of being characterized by impaired embryo development. So, we wonder if the utilization in FET cycles of leftover embryos that reached to blastocyst stage or those that eventually reached day 5 for aneuploidy testing contributed to the clinical outcomes. Study design, size, duration In the past 7 years, we included 22,289 couples who underwent ICSI while the large majority (84.8%) received a fresh embryo transfer, of which 70.9% were transferred at day 3. Leftover embryos, together with those euploid after PGT-A at blastocyst stage, were replaced in subsequent FET cycles. The clinical outcomes including clinical pregnancy rate (CPR) and deliveries were compared between the fresh embryo transfer and those after FET in total and after PGT-A. Participants/materials, setting, methods Couples with male factor underwent ICSI in standard fashion using exclusively ejaculated sample. For fresh embryo transfer cycles, embryos were transferred either at day 3 or at day 5. For FET cycles, embryos were cultured up to exclusively blastocyst stage and cryopreserved by vitrification. For aneuploidy, NGS was carried out for PGT-A. FET was carried out in natural or programmed cycles. Main results and the role of chance In the cohort underwent fresh embryo transfer, 18,896 couples underwent 37,751 ICSI cycles, where 322,916 oocytes were injected and 243,768 (75.5%) fertilized. Additionally, 3,393 patients received 4,712 FET in total with a fertilization of 69.8% (46,163/66,171) that did not differ from the fresh transfer group. The number of average embryos transferred in fresh cycles was 2.4±2 while FET was carried out exclusively on single embryo. Fresh transfer yielded 37.3% (14,087/37,751) CPR, while overall FET cycles achieved a higher CPR at 52.2% (2,462/4,712, P&amp;lt;0.0001). Similarly, the delivery rate in fresh cycles was 31.8% (12004/37751) and became 45.5% (2145/4712) in the FET (P&amp;lt;0.0001). To identify the advantage of selecting a single euploidy embryo, we compared FET on leftover unscreened blastocyst to those that were planned for PGT-A. Spare embryo transfers involved 1774 patients in 2282 cycles with a fertilization rate of 67.7% (18,905/27,937). For the PGT-A cycles, 1619 couples in 2430 cycles achieved a comparable fertilization rate of 71.3% (27,258/38,234), In this comparison, the FET on spare unscreened embryos achieved a CPR at 47.0% (1,072/2,282) while in the PGT-A group reached CPR at 57.2% (1390/2430, P&amp;lt;0.0001). Similarly, the delivery rate was 37.6% (857/2,282) in the FET and PGT-A was 53.0% (1,288/2,430) (P&amp;lt;0.0001). Limitations, reasons for caution The comparison is retrospective and is carried out on male factor infertility where day 3 embryo transfer were performed almost exclusively on fresh cycle to overcome poor embryo development. Nonetheless, those spare embryos that reached blastocyst stage and those that electively underwent aneuploidy testing significantly contributed to enhance clinical outcomes. Wider implications of the findings ICSI can overcome most of male infertility; however, the risk of impaired embryo development proposes a transfer at cleavage stage. The advanced embryo culture condition together with time-lapse allowed us to monitor embryos up to the blastocyst stage that once transferred, improving clinical outcomes, especially for embryos with confirmed euploidy. Trial registration number N/A

Objective: The objective of this study is to compare the pregnancy outcomes of the couples who underwent Hypo-Osmotıc Swelling Test (HOST) as a sperm selection method in Intracytoplasmic sperm injection (ICSI) – Frozen embryo transfer (ET) cycles and those who did not. Methods: ICSI – Frozen ET cycles, employing HOST as a sperm selection method were assigned to the Study Group; whereas those not employing HOST were included in the Control Group. Both study and control groups were divided into two subgroups according to the age of the women; those between the 25-35 years old and those between 36-40. The study and the control group included 509 and 1304 patients; respectively. Patients between 25-40 years old, who received Invitro fertilization (IVF) treatment for the first time, had good quality (grade A) blastocyst embryo on the 5th day, had normal semen parameters and HOST scores of b, c, and d were included in the study. Results: Pregnancy outcomes were comparable between cycles using HOST and not using HOST in 25-35 years group. However, cycles employing HOST showed significantly higher pregnancy rate (p = 0.023), clinical pregnancy rate (p = 0.005), and live birth rate (p = 0.045) as compared to cycles not using HOST, in the 36-40 years group. Conclusion:With normal semen parameters, the use of HOST in ICSI-Frozen ET cycles does not increase live birth rates in women aged 25-35, while it increases the rate of live births in women aged 36-40.

To evaluate the effects of different ovarian stimulation protocols on in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes in infertile women with adenomyosis. We carried out a retrospective cohort study among infertile women with adenomyosis receiving IVF/ICSI treatment, including 257 fresh embryo transfer (ET) cycles and 305 frozen embryo transfer (FET) cycles. In fresh ET cycles, ultra-long, long, short, and antagonist protocols were adopted. In FET cycles, patients received long-acting GnRH agonist (GnRHa) pretreatment or not. The primary outcome was clinical pregnancy rate (CPR), and the secondary outcomes included implantation rate (IR), miscarriage rate (MR), and live birth rate (LBR). In fresh ET cycles, compared with ultra-long and long protocols, IR (49.7%, 52.1% versus 28.2%, P=0.001) and CPR (64.3%, 57.4% versus 35.6%, P=0.004) significantly decreased in the short protocol. Similarly, compared with ultra-long and long protocols, a decreased inclination of IR (49.7%, 52.1% versus 33.3%) and CPR (57.4%, 64.3% versus 38.2%) existed in the antagonist protocol, although no statistical significance was detected because of strict P adjustment of Bonferroni method (Padj=0.008). Compared with long protocol, LBR in short protocol decreased obviously (48.2% versus 20.3%, P<0.001). In FET cycles, no matter which origin of embryos, there were no statistical differences in IR, CPR, and LBR. For women ≥35 years receiving fresh ET, CPR was higher in ultra-long and long protocols (52.1%, 50.0% versus 20.0%, 27.5%, P=0.031) compared to antagonist and short protocols. For women ≥35 years receiving FET, compared with ultra-long and antagonist protocols, cycles with embryos originating from long and short protocols had higher proportions of long-acting GnRHa pretreatment (30.4%,30.00 versus 63.9%, 51.4%, P=0.009). IR (61.1%, 48.6% versus 32.6%, 25.0%, P=0.020) and CPR (58.3%, 48.6% versus 30.4%, 25.0%, P=0.024) in long and short protocols were higher than rates of ultra-long and antagonist protocols, but no statistical differences were supported because of strict Bonferroni method (Padj=0.008). In infertile women with adenomyosis, if a fresh embryo was planned for transfer, an ultra-long or long protocol might be beneficial. If antagonist and short protocols were used, whole embryos frozen followed by FET was recommended. In FET cycles, embryos derived from different protocols had no impact on pregnancy outcomes.

Dydrogesterone and 20α-dihydrodydrogesterone plasma levels on day of embryo transfer and clinical outcome in an anovulatory programmed frozen-thawed embryo transfer cycle: a prospective cohort study.

Prepregnancy levels of antimüllerian hormone do not impact the perinatal outcomes in women with polycystic ovary syndrome.

Ectopic pregnancy (EP) is increasingly found in women treated with in vitro fertilization and embryo transfer (IVF–ET). With the development of the freeze-all policy in reproductive medicine, it is controversial whether frozen embryo transfer (FET) could reduce the rate of EP. In this single-center, large-sample retrospective study, we analyzed 16,048 human chorionic gonadotrophin (hCG)-positive patients who underwent fresh embryo transfer (ET) or FET cycles between January 2013 and March 2022. Throughout the study, the total EP rate was 2.09% (336/16,048), 2.16% (82/3803) in the ET group, and 2.07% (254/12,245) in the FET group. After adjustment for age, infertility causes, and other confounding factors, logistic regression results showed no statistical difference in EP rates between FET and ET groups (odds ratio (OR) 0.93 (0.71–1.22), p > 0.05). However, among the 3808 patients who underwent fresh ET cycles, the OR for EP was significantly lower in the long agonist protocol group than in the gonadotropin-releasing hormone antagonist (GnRH-ant) protocol group (OR 0.45 (0.22–0.93), p < 0.05). Through a large retrospective study, we demonstrated a slightly lower EP rate in FET cycles than in fresh ET cycles, but there was no significant difference. The long agonist protocol in ET cycles had a significantly lower risk of EP than the GnRH-ant protocol.

The studies posits that there is not sufficient evidence to support the use of intrauterine platelet-rich plasma (PRP) infusion in patients with recurrent implantation failure (RIF). This study aims to investigate the effects of infusion of PRP on patients with unexplained-RIF in fresh and frozen embryo transfer (ET) cycles. A total of 80 participants were included in this study. The participants were randomly assigned to one of two groups with and without PRP infusion. Each of the PRP and control groups were also divided into fresh and frozen ET subgroups. ET outcomes were compared between groups. Clinical pregnancy rate was significantly higher in Frozen ET in PRP group than other subgroups (p < 0.0001). Miscarriage rate were significantly lower in PRP group than control group. Pregnancy complications and preterm labor were significantly higher in PRP group than control group (p < 0.0001). Live birth and healthy baby rate were significantly higher in PRP group than control group (p < 0.0001). The intrauterine infusion of 0.8-1 ml of PRP 48 h before blastocyst ET at fresh and frozen cycles can be an efficient treatment option for u-RIF patients. Also, results indicated that the clinical pregnancy rate was equal to the live birth rate at fresh ET cycles, whereas the live birth rate was lower than the clinical pregnancy rate at frozen ET cycles. Therefore, considering the superiority of fresh cycles over freeze cycles, the infusion of PRP into the uterus of patients with RIF is recommended to be done at fresh ET cycles.Trial registration: NCT, NCT03996837. Registered 25/06/2019. Retrospectively registered, http://www.clinicaltrial.gov/ NCT03996837.

Comprehensive chromosome screening of trophectoderm with vitrification facilitates elective single-embryo transfer for infertile women with advanced maternal age