Single Frozen Embryo Transfer Research Articles

Maternal Placental Growth Factor (PlGF) levels, sonographic placental parameters, and outcomes of IVF pregnancies with and without embryo trophectoderm biopsy.

In vitro fertilization (IVF) is associated with abnormal trophoblast invasion and resultant decreased levels of circulating placental biomarkers such as placental growth factor (PlGF).Our objective was to evaluate maternal serum levels of second/third trimester PlGF, sonographic placental parameters, and clinical outcomes among IVF frozen embryo transfer (FET) pregnancies with and without embryo trophectoderm biopsy. This was a retrospective study of pregnant patients who conceived using a single frozen embryo transfer (FET) and gave birth between 30 January 2018 and 31 May 2021. We compared PlGF levels, sonographic placental parameters, and clinical outcomes between FET with biopsy and FET without biopsy groups. The median PlGF level was 614.5 pg/mL (IQR 406-1020) for FET pregnancies with biopsy, and 717.0 pg/mL (IQR 552-1215) for FET pregnancies without biopsy. The adjusted mean difference was 190.9 pg/mL lower in the FET biopsy group (95% CI, -410.6, 28.8; p = 0.088). There were no statistically significant differences in placental parameters or clinical pregnancy outcomes. This exploratory study demonstrated a possible trend toward lower maternal serum PlGF in the pregnancies conceived with FET using a biopsied embryo. Further investigation is warranted into the potential placental health effects of trophectoderm biopsy.

O-316 Clinical application of PGT-A for recurrent pregnancy loss, what effects live birth after single euploid blastocyst transfer?

Abstract Study question Which factors effect the likelihood of live birth after euploid frozen embryo transfer (FET) in recurrent pregnancy loss (RPL)? Summary answer Female age and number of previous pregnancy loss do not effect the live birth rates after euploid blastocyst FET. What is known already PGT-A is helpful to discard the aneuploid embryos and has been proven to improve pregnancy outcomes and reduce miscarriage rate per embryo transfer. As approximately 50% of clinical miscarriages have chromosomal abnormalities, PGT-A has been suggested as a treatment option for RPL. However it is questionable on the cost effectiveness, effect on prognosis and labor-intensive. In addition, currently PGT-A use is not recommended by any society guidelines in RPL patients. ESHRE guideline on RPL stated ‘All couples with results of an abnormal fetal or parental karyotype may be informed about the possible treatment options available including their advantages and disadvantages.’ Study design, size, duration This retrospective cohort study from January 2018 to January 2023 was conducted at Bahçeci Health Group included patients underwent PGT-A/ICSI cycles. Patients with RPL (2 or more clinical pregnancy loss) had a complete RPL workup recommended by ASRM and reported no etiology for RPL was included in the study. Patients with uterine synechia, hydrosalpinx, endocrinological disorders and thin endometrium (endometrial thickness <6mm) were excluded Participants/materials, setting, methods A total of 366 single euploid blastocyst FETs employing hormone replacement therapy for endometrial preparation were evaluated. Patients were categorized into 2 group regarding female age (female age< 35 years and female age≥35 years. Demographic, embryological and endocrinological parameters were analyzed. Live birth rate (LBR) was the primary outcome. Clinical pregnancy rate (CPR) and miscarriage rate (MR) were the secondary outcome. Main results and the role of chance The mean female age of the study population was 33.9±4.6 years, the number of previous pregnancy loss was 3.2±1.6 and BMI was 23.8 ±7.9 kg/m2. Overall CPR, MR and LBR were 61.7% (226/366), 24.8% (56/226) and 46.5% (170/366) respectively. Comparison of clinical characteristics of the 195 women <35 years and 171 women ≥35 years revealed no significant deference in BMI, number of previous live birth, and number of previous pregnancy loss. CPR, MR and LBR were similar among two groups [ 63.6% (124/195) vs 59.6% (102/171), p = 0.44; 27.4% (34/124) vs 21.6% (22/102), p = 0.31; 46.2% (90/195) vs 46.8% (80/171), p = 0.9; respectively]. Binary logistic regression evaluating the independent factors that effect live birth revealed that female age and number of previous pregnancy loss were not found to be statistically significant factors. The only independent factor for live birth was day of embryo biopsy, transferring the day 6 biopsied embriyo significantly decreased the live birth [p = 0.003, OR: 0.47, 95% CI (0.29-0.77)]. Limitations, reasons for caution The maim limitation of the study is its retrospective nature. Wider implications of the findings PGT-A has been suggested to be a treatment for RPL. However there is insufficient data to call PGT-A as an efficient treatment for RPL. Investigating the factors that effect live birth after PGT-A may be the first step for selecting the most favorable group Trial registration number Not applicable

P-613 Natural cycles monitoring for frozen embryo transfers: is it beneficial to start immediately after ovarian stimulation?

Abstract Study question Are there more advantages in performing frozen embryo transfer (FET) immediately after ovarian stimulation or in delaying it by at least one menstruation? Summary answer In natural cycles, timing of frozen embryo transfer does not affect clinical pregnancy rates, but immediate transfer is associated with higher rates of cycle cancellation. What is known already In order to achieve a reduced time to pregnancy and avoid additional stress for the couple, some Centers initiate FETs immediately, i.e. on the first menstrual cycle after ovarian stimulation. However, the detrimental effect of hormonal stimulation on ovarian function and endometrial receptivity may persist in the following cycle and immediate FETs may increase the possibility of cycle cancellation and reduce pregnancy rate. Available evidence on this subject, mainly focused on endometrial preparation with hormonal replacement therapy (HRT), showed contrasting results. Moreover, studies on FETs performed on natural cycles are lacking. Study design, size, duration This is a retrospective study conducted at the Infertility Unit of the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico in Milan, Italy. A large amount of single FETs, performed between 2014 and 2021, was considered and was then divided in two groups according to their timing (immediate or delayed). The primary outcome was to assess the clinical pregnancy rate (CPR); secondary outcomes were live birth rate (LBR) and the cycle cancellation rate. Participants/materials, setting, methods True natural cycles (T-NC) and modified cycles with the use of triggered ovulation (M-NC) protocols for endometrial preparation were pursued in women with regular menses; otherwise, HRT was used. Immediate FET was defined when performed on the first menstruation following ovarian stimulation (i.e. withdrawal bleeding occurring after ovarian stimulation or after a failed fresh embryo transfer). Delayed FETs included those performed after at least two menstruations. Only the first transfer after ovarian stimulation was considered. Main results and the role of chance A total of 5,765 FET cycles were included in the study. FET cycles were achieved through T-NC in 4,477 cases (78% of all FETs), of which 364 were immediate and 4,113 were delayed. M-NC cycles accounted for 1% of the total amount of FETs and HRT protocols were pursued in 11% of cases. The analysis showed no impact of FET timing on CPR both in the whole cohort and in the subgroups based on different endometrial preparation protocols. Focusing on T-NC cycles, the CPR in the immediate group was comparable to that of the postponed group (29 vs. 32% respectively, OR 0.90 [95% CI 0.71 - 1.14]). On the other hand, LBR in T-NC cycles was significantly lower in the immediate group than in the delayed group (20% vs. 25% respectively, OR 0.74 [95% CI 0.56 - 0.96]). Consequently, immediate FETs resulted to be associated with a significantly higher rate of pregnancy loss (31% vs. 21% respectively, p = 0.03). Furthermore, cycle cancellation occurred more frequently in the immediate T-NC group, compared with the delayed group (18% vs. 12% respectively, p = 0.003). Similar results were observed in HRT cycles (15% in immediate FETs vs. 7% in delayed FETs, p = 0.08). Limitations, reasons for caution The retrospective nature of this study involves a risk of selection bias. Moreover, the reason for cycle cancellation was not always available; thus, these data were not included in the analysis. Lastly, these outcomes are only applicable to a similar cohort, that is Centers following a non-elective freeze-all policy. Wider implications of the findings This is the largest investigation on T-NC FETs and is among the very few studies providing separate results on different endometrial preparation protocols. Evidence from this study is in line with some previous retrospective analyses and in contrast with others. Thus, randomized controlled trials are needed to confirm these results. Trial registration number not applicable

Effect of time post warming to embryo transfer on human blastocyst metabolism and pregnancy outcome.

This study is aiming to test whether variation in post warming culture time impacts blastocyst metabolism or pregnancy outcome. In this single center retrospective cohort study, outcomes of 11,520 single frozen embryo transfer (FET) cycles were analyzed from January 2015 to December 2020. Patient treatments included both natural and programmed cycles. Time categories were determined using the time between blastocyst warming and embryo transfer: 0 (0- <1h), 1 (1-<2h), 2 (2-<3h), 3(3-<4h), 4 (4-<5), 5 (5-<6), 6 (6-<7) and 7 (7-8h). Non-invasive metabolic imaging of discarded human blastocysts for up to 10h was also performed using Fluorescence lifetime imaging microscopy (FLIM) to examine for metabolic perturbations during culture. The mean age of patients across all time categories were comparable (35.6 ± 3.9). Live birth rates (38-52%) and miscarriage rate (5-11%) were not statistically different across post-warming culture time. When assessing pregnancy outcomes based on the use of PGT-A, miscarriage and live birth rates were not statistically different across culture hours in both PGT-A and non-PGT cycles. Further metabolic analysis of blastocysts for the duration of 10h of culture post warming, revealed minimal metabolic changes of embryos in culture. Overall, our results show that differences in the time of post warming culture have no significant impact on miscarriage or live birth rate for frozen embryo transfers. This information can be beneficial for clinical practices with either minimal staffing or a high number of patient cases.

The combination of dydrogesterone and micronized vaginal progesterone can render serum progesterone level measurements on the day of embryo transfer and rescue attempts unnecessary in an HRT FET cycle.

To evaluate the role of serum progesterone (P4) on the day of embryo transfer (ET) when dydrogesterone (DYD) and micronized vaginal progesterone (MVP) are combined as luteal phase support (LPS) in a hormone replacement therapy (HRT) frozen ET (FET) cycles. Retrospective study, including single euploid HRT FET cycles with DYD and MVP as LPS and P4 measurement on ET day. Initially, patients with P4 levels < 10 ng/ml increased MVP to 400 mg/day; this "rescue" was abandoned later. 560 cycles of 507 couples were included. In 275 women, serum P4 level was < 10 ng/ml on the ET day. Among those with low P4 levels, MVP dose remained unchanged in 65 women (11.6%) and was increased in 210 women (37.5%). Women with P4 levels ≥ 10 ng/ml continued LPS without modification. Overall pregnancy rates in these groups were 61.5% (40/65), 54.8% (115/210), and 48.4% (138/285), respectively (p = n.s.). Association of serum P4 levels with ongoing pregnancy rates was analyzed in women without any additional MVP regardless of serum P4 levels (n = 350); multivariable analysis (adjusted for age, BMI, embryo quality (EQ)) did not show a significant association of serum P4 levels with OPR (OR 0.96, 95% CI 0.90-1.02; p = 0.185). Using inverse probability treatment weights, regression analysis in the weighted sample showed no significant association between P4 treatment groups and OP. Compared to fair EQ, the transfer of good EQ increased (OR 1.61, 95% CI 1.22-2.15; p = 0.001) and the transfer of a poor EQ decreased the odds of OP (OR 0.73, 95% CI 0.55-0.97; p = 0.029). In HRT FET cycle, using LPS with 300 mg/day MVP and 30 mg/day DYD, it appears that serum P4 measurement and increase of MVP in patients with P4 < 10 ng/ml are not necessary.

Is endometrial receptivity affected in women with endometriosis? Results from a matched pair case-control study of assisted reproductive technology treatments

Research questionIs endometriosis detrimental to embryo implantation? DesignA retrospective matched case-control study of women with a surgical or ultrasound diagnosis of endometriosis at Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico di Milano between 2015 and 2021. Women with endometriosis who underwent a ‘freeze-all’ cycle during an IVF treatment were eligible to be included. They were matched to patients without the disease, who also underwent cryopreserved blastocyst transfer cycles, in a 1:1 ratio by age (±1 year), and number (=) and quality (±1 top versus low) of cryopreserved blastocysts. All women underwent single frozen embryo transfer, and assisted reproductive technology outcomes suggested by the Core Outcome Measure for Infertility Trials initiative were evaluated. The main outcome was the cumulative live birth rate per cycle. ResultsOne hundred and one women with endometriosis and 101 matched unaffected women were included. Cumulative live birth rate per cycle did not vary between women with and without endometriosis (50% versus 58%, respectively; P = 0.32). On the basis of the Kaplan–Meier analysis, the predicted success rates over four embryos transferred were also similar (74% versus 82%, respectively; P = 0.67). ConclusionIn women with moderate or severe endometriosis, these retrospective results seem to indicate no or a limited effect of the disease on endometrial receptivity.

Euploid programmed frozen embryo transfer cycles are associated with a higher live birth rate when estradiol levels more closely mimic physiology

To determine whether peak estradiol (E2) levels above the usual physiologic range (300-500 pg/mL) will impact programmed frozen embryo transfer (FET) outcomes in an ideal study population of those using good-quality single euploid blastocysts. Retrospective cohort study. University-based clinic. Single euploid-programmed FET done at a single academic institution from January 2016 to December 2019. The population was divided into three groups on the basis of peak serum E2 levels during endometrial preparation: group A (E2 <300 pg/mL), group B (300-500 pg/mL), and group C (>500 pg/mL). Group B was used as the reference range for statistical analysis. Frozen embryo transfer cycles. The primary outcome was the live birth rate (LBR). Secondary outcomes included implantation, biochemical,ectopic, and miscarriage rates. A total of 750 FET cycles were included in this study. Poisson regression analysis showed a negative impact of higher peak E2 on the LBR. A decrease in LBR was noted between group C and referent group B (50.2% vs. 63.4%, risk ratio 0.79 [0.68-0.91]) and group A and referent group B (42.5% vs. 63.4%, risk ratio 0.67 [0.46-0.98]). Secondary outcomes were notable for a lower implantation rate when groups A and C were compared with group B and a higher biochemical rate between group C and group B. There was no notable difference between groups in ectopic or miscarriage rates. Limiting peak serum E2 levels to 300-500 pg/mL during programmed FET cycles is associated with improved LBRs compared with cycles with peak E2 levels of <300 pg/mL or >500 pg/mL in an ideal study population.

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

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

Phytoestrogens Present in Follicular Fluid and Urine Are Positively Associated with IVF Outcomes following Single Euploid Embryo Transfer

The impact and safety of phytoestrogens, plant-derived isoflavones with estrogenic activity predominantly present in soy, on female reproductive health and IVF outcomes continues to be hotly debated. In this prospective cohort study, 60 women attending IVI-RMA New Jersey undergoing IVF with single frozen embryo transfer (SET/FET) of good-quality euploid blastocyst after PGT-A analysis were recruited. Concentrations of two phytoestrogens (daidzein and genistein) in follicular fluid (FF) and urine (U) were measured by UPLC–MSMS, both collected on vaginal oocyte retrieval day. These measurements correlated with IVF clinical outcomes. In models adjusted for age, BMI, race/ethnicity, and smoking status, higher FF phytoestrogen concentrations were significantly associated with higher serum estradiol, enhanced probability of implantation, clinical pregnancy, and live birth. Moreover, higher urine phytoestrogen concentrations were significantly associated with improved oocyte maturation and fertilization potential and increased probability of clinical pregnancy and live birth. Finally, higher FF and urine phytoestrogen concentrations were associated with a higher probability of live birth from a given IVF cycle. Our results suggest that dietary phytoestrogens improved reproductive outcomes of women undergoing IVF treatment. However, additional prospective studies are needed to optimize the use of phytoestrogens to further enhance reproductive outcomes and/or protect against reproductive insults.

O-194 Blastulation timing in embryos is influenced by ploidy and is a predictor of transfer outcome

Abstract Study question Is there an association of the timing of blastulation (TE biopsy day) on embryo ploidy and pregnancy outcome after frozen embryo transfer? Summary answer Blastocysts expanded on day 5 are more likely to be euploid and result in an ongoing pregnancy after single euploid frozen embryo transfer (FET). What is known already Embryo selection for ET is commonly based on static morphological parameters for patients undergoing in vitro fertilization (IVF). Embryo quality on the day of biopsy in combination with preimplantation genetic testing (PGT) are considered important predictors for successful implantation. At present, coherent data regarding any association between the timing of blastulation with embryo ploidy and pregnancy outcomes following single FET are lacking. The aim of our study was to investigate the correlation of the culturing method and blastulation day (day 5/6/7) with embryo ploidy and outcomes of matched d5 vs d6 vs d7 FET cycles. Study design, size, duration This retrospective cohort study was performed at the CReATe Fertility Centre and its Reproductive Genetics Laboratory, between January 2019-December 2022. 29660 blastocysts from 5302 cycles (3645 patients) were analyzed using high resolution NGS PGT-A (10Mb resolution for copy number variations and 30%-70% for mosaicism). Pregnancy outcome data from 3942 single-FETs were analyzed. Average age of ovum provider was 32.9±5.8 and sperm provider 39.1±6.4. Clinical, laboratory and demographic data were obtained for statistical analysis. Participants/materials, setting, methods Embryos were allocated into four groups based on static morphological grading before biopsy on either d5 (n = 8312), d6 (n = 19183) or d7 (n = 2165): Good (&amp;gt;1/2BB), n = 5648, Average (1BB, 2BB), n = 10492, Poor (&amp;lt;1/2 BB) n = 12219 and Early blast, n = 1301. Embryo ploidy in each group and pregnancy outcomes from single euploid FET were compared between matched cycles of day 5 biopsy to days 6 and 7. Main results and the role of chance PGT-A analysis of 29660 embryos showed 53.1% were euploid, 33.9% were aneuploid and 13.0% were mosaic. There were significantly higher proportion of euploid embryos among those biopsied on d5 compared to d6 and d7 with average morphology grade (p = 0 O.R.=1.35979; p = 0.008098 O.R.=1.34442), poor (p = 0 O.R.=1.76481; p = 0 O.R.=2.73903) and early grades (p = 0 O.R.=2.71891; p = 0 O.R.=2.74271), but not among embryos with good grade (p = 0.244399 O.R.=1.07276; p = 0.182084 O.R.=1.38189). Ongoing pregnancy rates were significantly higher for d5 vs d6 biopsied embryos, for all morphology grade groups: good (p = 0.030036 O.R.=1.26598), average (p = 0 O.R.=1.80782), poor (p = 0.000303 O.R.=1.89235) and early blasts (p = 0.049501 O.R.=3.30556). D5 blasts had higher ongoing pregnancy rates compared to d7 among average and poor morphology grade as well as early blast (p = 0.000419 O.R.=8.93182, p = 0.000036 O.R.=7.29464, p = 0.010034, respectively), except among good grade embryos (p = 0.885598 O.R.=0.9028). Continuous culture of embryos in Embryoscope™ versus conventional incubator did not influence the ploidy (n = 24321; n = 4756, respectively) or the pregnancy outcome after FET (n = 3134; n = 752, respectively) while comparing between each day of biopsy. Limitations, reasons for caution Although this is the largest sample size study to investigate the association of blastulation with ploidy and pregnancy outcomes, the sample size for d7 embryos is relatively low and results should be confirmed in a bigger study. Wider implications of the findings Prioritization of euploid embryos for transfer should consider the timing to blastulation and embryos biopsied on d5 should be considered before those biopsied on d6 or d7. This data has potential to shed light on the impact of normal chromosomal content on preimplantation embryo development. Trial registration number not applicable

P-301 Assessment of ongoing clinical outcomes prediction of an AI system on retrospective SET data

Abstract Study question Would patients with fresh and frozen embryo transfer had achieved pregnancy before if the embryo was chosen by AI? Summary answer CHLOE (AI) can predict pregnancy, ongoing clinical pregnancy, and miscarriage following a single embryo transfer (SET). What is known already The use of time-lapse incubators has provided embryologists with more information to evaluate embryo development, resulting in varying clinical practices among clinics in prioritizing this information. However, manual annotation of time-lapse videos is time-consuming and prone to interoperator inconsistencies. To overcome these challenges, AI tools like CHLOE (Fairtility) can be utilized. CHLOE uses AI-based predictors to predict implantation and provides clarity on the biological factors driving these predictions. However, before incorporating AI tools into clinical practice, it is important to validate their effectiveness. Study design, size, duration Single study center that took place between July of 2021 and December 2022 at a private clinic in Spain. This was a retrospective cohort analysis that reviewed 118 time-lapse videos from single fresh embryo transfers and 92 time-lapse videos from single frozen embryo transfers with known ongoing clinical pregnancy outcome. CHLOE EQ score and CHLOE Rank efficacy of prediction of clinical outcomes and miscarriage was quantified using the metric AUC. Participants/materials, setting, methods Time-lapse videos were evaluated using CHLOE (Fairtility), an AI tool, to determine CHLOE EQ score and rank related to clinical outcomes (biochemical pregnancy, clinical pregnancy, and miscarriage) following fresh and frozen SET. CHLOE rank and embryology were compared with chi-square and AUC was calculated with logistic regression to measure prediction accuracy. T-test was used to check differences in CHLOE EQ score in different outcomes. Main results and the role of chance Embryologist vs CHLOE Ranking weren’t significant (p &amp;gt; 0.05). In fresh SET the mean EQ score was 7.76, and in frozen SET was 7.07. Following fresh SET, CHLOE EQ score was not-significantly predictive of biochemical pregnancy (AUC = 0.53, n = 104, p = 0.462), clinical pregnancy (AUC = 0.51, n = 79, p = 0.949), and miscarriage rate (AUC = 0.50, n = 68, p = 0.949); CHLOE Ranking was more predictive than embryologist rank for biochemical pregnancy (embryologist vs CHLOE rank: AUC = 0.51, p &amp;gt; 0.05 vs AUC = 0.61, p &amp;gt; 0.05), clinical pregnancy (embryologist vs CHLOE rank: AUC = 0.51, p &amp;gt; 0.05 vs AUC = 0.70, p &amp;gt; 0.05) and miscarriage rate (embryologist vs CHLOE rank: AUC = 0.51, p &amp;gt; 0.05 vs AUC = 0.75, p &amp;gt; 0.025). Following frozen SET, only top 1 embryos ranked by embryologists were transferred, and CHLOE EQ score was predictive of biochemical pregnancy (AUC = 0.60, n = 85, p = 0.213), clinical pregnancy (AUC = 0.64, n = 60, p = 0.919), and miscarriage rate (AUC = 0.87, n = 52, p = 0.437); CHLOE Ranking was predictive of biochemical pregnancy (AUC = 0.59, p &amp;gt; 0.05), clinical pregnancy (AUC = 0.64, p &amp;gt; 0.05) and miscarriage rate (AUC = 0.90, p &amp;gt; 0.05). Limitations, reasons for caution This study is a single-center retrospective analysis where embryos were chosen for transfer by human embryologists and is part of a broader effort to validate the responsible integration of AI into clinical practice. Wider implications of the findings The use of AI-based tools has the possibility to enhance the consistency, efficiency, and effectiveness of embryo selection. The information from quantitative and qualitative morphokinetics provided by AI tools like CHLOE brings greater clarity to predictions, enabling more personalized care for each individual embryo. Trial registration number Not Applicable

Monozygotic dichorionic-diamniotic twin pregnancy after a single frozen embryo transfer in a spontaneous ovulation : about a case report

Monozygotic dichorionic-diamniotic twin pregnancy after a single frozen embryo transfer in a spontaneous ovulation : about a case report

A balancing act: sex selection after pre-implantation genetic testing for aneuploidy for first versus second baby.

How often do patients undergoing frozen embryo transfer (FET) after preimplantation genetic testing for aneuploidy (PGT-A) choose to select for sex and do sex selection rates differ before and after successful delivery of a first baby? When a choice was available between male and female embryos, patients selected the sex more frequently when trying to conceive the second child (62%) as compared to the first child (32.4%) and most commonly selected for the opposite sex of the first child. Sex selection is widely available in US fertility clinics. However, the rate of sex selection for patients undergoing FET after PGT-A is unknown. This is a retrospective cohort study of 585 patients that took place between January 2013 and February 2021. The study took place at a single, urban academic fertility center in the USA. Patients were included if they had a live birth after single euploid FET and returned for at least one subsequent euploid FET. The primary outcomes were the rates of sex selection for first versus second baby. Secondary outcomes were rate of selection for same versus opposite sex as first live birth and overall rate of selection for males versus females. Five hundred and eighty-five patients underwent a total of 1560 single euploid FETs resulting in either one or two live births. A choice between male and female euploid embryos was available for 919 FETs (first child: 67.5% (519/769) versus second child: 50.6% (400/791), P < 0.01). When a choice was available, patients selected the sex more frequently when trying to conceive the second child (first child: 32.4% (168/519) versus second child: 62.0% (248/400), P < 0.01). When sex was selected after first live birth, the opposite sex of the first child was selected 81.8% (203/248 FETs) of the time. Of transfers that involved sex selection, rates of male and female selection were similar for the first child, but selection for females was greater for the second child (first child: 51.2% (86/168) male versus 48.9% (82/168) female, second child: 41.1% (102/248) male versus 58.9% (146/248) female, P < 0.04). The study was performed at one urban academic medical center in the Northeastern US, which may limit generalizability to other settings where PGT-A may be performed less frequently, or sex selection may be limited or not permitted. In addition, we could not reliably account for whether patients or their partners had prior children and if so, of what sex. Patients undergoing PGT-A with both male and female euploid embryos were more likely to select for sex when attempting a second child and usually selected for the opposite sex of their first child. These findings highlight the potential for family balancing for patients who undergo PGT-A in settings where sex selection is permitted. This study received no funding. The authors have no conflicts of interest to declare. N/A.

Modified natural and optimized programmed frozen embryo transfers have equivalent live birth rates: an analysis of 6,682 cycles

To compare the live birth rates (LBRs) in modified natural and programmed single blastocyst frozen embryo transfer (FET) cycles. Retrospective cohort study. University-affiliated fertility practice. Patients who underwent single blastocyst FETs between January 2014 and December 2019. A total of 15,034 FET cycles from 9,092 patients were reviewed; 1,186 modified natural and 5,496 programmed FET cycles from 4,532 patients met the inclusion criteria for analysis. No intervention. The primary outcome measure was the LBR. There was no difference in live birth after programmed cycles using intramuscular (IM) progesterone or a combination of vaginal progesterone and IM progesterone compared with that after modified natural cycles (adjusted relative risks, 0.94 [95% confidence interval {CI}, 0.85-1.04] and 0.91 [95% CI, 0.82-1.02], respectively). The relative risk of live birth decreased in programmed cycles that used exclusively vaginal progesterone compared with that in modified natural cycles (adjusted relative risk, 0.77 [95% CI, 0.69-0.86]). The LBR decreased in programmed cycles that used only vaginal progesterone. However, no difference in the LBRs existed between modified natural and programmed cycles if programmed cycles used either IM progesterone or a combination of IM and vaginal progesterone protocols. This study demonstrates that modified natural FET cycles and optimized programmed FET cycles have equivalent LBRs.

The influence of day 3 embryo cell number on the clinical pregnancy and live birth rates of day 5 single blastocyst transfer from frozen embryo transfer cycles

BackgroundTo evaluate the influence of day 3 embryo cell number on the clinical pregnancy and live birth rates of day 5 single blastocyst transfer in frozen embryo transfer (FET) cycles.MethodsOur retrospective study included 3761 day 5 single blastocyst FET cycles between January 2015 and December 2019. These FET cycles were divided into three groups according to the day 3 embryo cell number: 939 cycles in the < 8-cell group, 1224 cycles in the 8-cell group and 1598 cycles in the > 8-cell group. The clinical pregnancy and live birth rates were compared among the three groups.ResultsThe clinical pregnancy rate of day 5 single blastocyst transfer in FET cycles increased significantly as the day 3 embryo cell number increased (52.2%, 61.4% and 66.8%, P < 0.001). Similarly, the live birth rate increased significantly as the day 3 embryo cell number increased (42.7%, 49.8% and 54.9%, P < 0.001). The results of the subgroup analysis showed that the clinical pregnancy and live birth rates were not significantly different among the three groups when good-quality blastocysts were transferred. The clinical pregnancy and live birth rates increased significantly as the day 3 embryo cell number increased when fair- and poor-quality blastocysts were transferred.ConclusionThe day 3 embryo cell number needs to be considered when day 5 single blastocyst transfer is performed in FET cycles, especially when fair- and poor-quality blastocysts are used for transfer. The transfer of a day 5 single blastocyst derived from an embryo with faster development on day 3 may shorten the time to achieving a live birth.

Impact of cell loss after warming of human vitrified day 3 embryos on obstetric outcome in single frozen embryo transfers.

Does cell loss (CL) after vitrification and warming (V/W) of day 3 embryos have an impact on live birth rate (LBR) and neonatal outcomes? This retrospective analysis includes cleavage stage day 3 embryos vitrified/warmed between 2011 and 2018. Only single vitrified/warmed embryo transfers were included. Pre-implantation genetic screening, oocyte donation, and age banking were excluded from the analysis. The sample was divided into two groups: group A (intact embryo after warming) and group B (≤ 50% blastomere loss after warming). On the total embryos (n = 2327), 1953 were fully intact (83.9%, group A) and 374 presented cell damage (16.1%, group B). In group B, 62% (232/374) of the embryos had lost only one cell. Age at cryopreservation, cause of infertility, insemination procedure, and semen origin were comparable between the two groups. The positive hCG rate (30% and 24.3%, respectively, for intact vs CL group, p = 0.028) and LBR (13.7% and 9.4%, respectively, for intact vs CL group, p = 0.023) per warming cycle were significantly higher for intact embryos. However, LBR per positive hCG was equivalent between intact and damaged embryos (45.6% vs 38.5%, respectively, p = 0.2). Newborn measurements (length, weight, and head circumference at birth) were comparable between the two groups. Multivariate logistic regression showed that the presence of CL is not predictive for LB when adjusting for patients' age. LBR is significantly higher after transfer of an intact embryo compared to an embryo with CL after warming; however, neonatal outcomes are comparable between the two groups.

P-518 Do mosaic embryos still stand a chance for pregnancy?

Abstract Study question To investigate the effect of embryo mosaicism on clinical IVF outcomes in single and double frozen embryo transfer (FET). Summary answer There is no statistical difference between the low/high mosaic and euploid embryos in regards to the pregnancy and miscarriage rate, in single and double FETs. What is known already During mitosis and meiosis, mis-segregation of chromosomes causes aneuploidy. Recent studies have shown that next-generation sequencing (NGS) based pre-implantation genetic test for aneuploidy (PGT-A) improve clinical IVF outcomes by detecting chromosomal abnormalities in human embryos. Euploid embryos have been confirmed to achieve a higher pregnancy, implantation and live birth rate than aneuploid embryos. However, mosaic embryos, which contain two or more cell lines with different chromosomal set, are yet controversial in the assisted reproductive medical field. Hence, comprehensive studies on the clinical IVF outcomes of mosaic embryo transfers (METs) are necessary to resolve the concerns of embryo mosaicism. Study design, size, duration This single centre retrospective study included 93 low mosaic embryos, which were transferred in 64 FET cycles (35 single and 29 double FET), and 27 high mosaic embryos from 18 FET cycles (9 single and 9 double FET), from January 2018 to October 2021. The pregnancy and miscarriage rate of the METs were compared to an euploid control group, which comprised of 184 euploid embryos from 124 FET cycles (64 single and 60 double FET). Participants/materials, setting, methods All embryos were cultured to blastocyst stage and trophectoderm (TE) biopsy was performed on day 5 or 6. NGS based PGT-A was conducted to detect chromosomal abnormalities. According to the Preimplantation Genetic Diagnosis International Society guideline, mosaic embryos were categorized into 2 groups: low (20-39% mosaicism) and high mosaic embryos (40-80% mosaicism). Pearson chi-square test was performed to compare the pregnancy and miscarriage rate between low/high METs and euploid group, in single and double FETs. Main results and the role of chance In single FET cycles, patients with low mosaic embryos transferred achieved a higher pregnancy rate than the patients with euploid (60% versus 42%) and high mosaic (60% versus 33%) embryos transferred. In addition, the miscarriage rate for low mosaic embryos (9%) was the lowest, compared to the the euploid (11%) and high mosaic (22%) embryos. On the other hand, the highest pregnancy and lowest miscarriage rate in double FET cycles were achieved by patients with euploid embryos transferred. Results showed that patients with euploid embryos transferred possessed a pregnancy rate of 68%, whereas patients with low and high mosaic embryos transferred showed a pregnancy rate of 48% and 56% respectively. As mentioned above, the euploid embryos resulted in a lower miscarriage rate than the low (3% versus 10%) and high mosaic (3% versus 11%) embryos in double FET cycles. However, it is important to highlight that the above mentioned differences between the low/high METs and euploid control group in respect of the pregnancy and miscarriage rate were not statistically significant, in both single and double FET cycles (p &amp;lt; 0.05). Limitations, reasons for caution The factors of patient’s age and blastocyst grading were not taken into account in this study. Hence, a larger-scale randomized trial is a need to further identify and resolve the concerns of embryo mosaicism in the assisted reproductive medical field . Wider implications of the findings In the PGT-A analysis, only a fraction of the TE within an embryo was tested. Thus, misclassification of embryos might occur. It is suggested that clinical management of mosaic embryos should be carefully reviewed in the case of patients with no euploid embryos to be transferred. Trial registration number NA

O-245 Clinical factors associated with low serum progesterone on the day of frozen blastocyst transfer in hormonal replacement therapy cycles

Abstract Study question Which factors are associated with low serum progesterone (P) levels on the day of frozen embryo transfer (FET), in hormonal replacement therapy (HRT) cycles? Summary answer Body Mass Index (BMI), parity, and non-European geographic origin are factors associated with low serum P levels on the day of FET in HRT cycles. What is known already While the detrimental impact of low serum P concentrations on HRT-FET outcomes is unanimously recognized, the factors accounting for P levels disparities among patients receiving the same luteal phase support treatment remain to be elucidated, in order to help clinicians predicting which subgroups of patients would benefit from a tailored P supplementation. Study design, size, duration Observational cohort study with 915 patients undergoing HRT-FET at a tertiary care university hospital, between January 2019 and March 2020. Participants/materials, setting, methods Patients undergoing single autologous blastocyst FET under HRT using exogenous estradiol and vaginal micronized progesterone for endometrial preparation. Women were only included once during the study period. The serum progesterone level was measured in the morning of the FET, in a single laboratory. Independent factors associated with low serum P levels (defined as ≤ 9.8 ng/mL, according to a previous published study) were analyzed using univariate and multivariate logistic regression models. Main results and the role of chance The live birth rate was 31.5% (288/915) in the overall population. Two hundred and twenty-six patients (24.7%) had a low serum P level, on the day of the FET. Univariate analysis showed that BMI (p &amp;lt; 0.001), parity (p = 0.001), non-European geographic origin (p = 0.001), and the duration of infertility (p = 0.018) were significantly associated with low serum P levels. Moreover, the proportion of active smokers was significantly lower in the “low P concentrations” group (p = 0.002). After multivariate analysis, BMI (OR 1.06 95%CI [1.02-1.11], p = 0.002), parity (OR 1.31 95%CI [1.04-1.65], p = 0.024), non-European geographic origin (OR 1.67 95%CI [1.19-2.35], p = 0.003), and active smoking (OR 0.43 95%CI [0.21-0.85], p = 0.016) remained independent factors associated with serum P levels ≤ 9.8 ng/mL. Limitations, reasons for caution The main limitation of our study is linked to its observational design. Extrapolation of our results to other laboratories, or other routes and/or doses of administering progesterone also needs to be validated. Wider implications of the findings There is urgent need for future research on clinical factors affecting P concentrations to help clinicians predicting which subgroups of patients would benefit from individualized luteal phase support. More data are also needed on the underlying mechanisms explaining the relationship between patients’ characteristics and serum P levels in HRT-cycles. Trial registration number NA

P-379 Ongoing pregnancy rate (OPR) of day (D) 7 euploid blastocysts is inferior to D5/D6 euploid blastocysts in frozen embryo transfer (FET) cycles

Abstract Study question Do delayed-grown D7 euploid blastocysts have similar OPRs as D5 or D6 euploid blastocysts in FET cycles? Summary answer Although OPR is significantly higher with D5/D6 euploid blastocysts than D7, patients aged &amp;gt;38 years might benefit when slow-developing blastocysts are routinely cultured till D7. What is known already Current IVF practice suggests that embryos of optimal development reach blastocyst stage 116±2 hours after insemination. Recently, high reproductive potential has been reported with D6 as well as with D7 blastocysts. Although D7 blastocysts have a delayed embryo development, euploidy rates range between 25% and 49% if biopsy is performed. Usable D7 blastocysts represent nearly 5% of embryos in IVF with acceptable pregnancy and live birth rates, however, data are still limited. Therefore, further evidence of FET outcomes with D5, D6 and D7 euploid blastocysts are needed to investigate whether prolonged in-vitro embryo culture till D7 should be performed routinely. Study design, size, duration A single centre observational study was performed between June 2017 and November 2021, including 1396 single euploid FET cycles with blastocysts biopsied on D5 (N = 795), D6 (N = 572) or D7 (N = 29). Patients underwent endometrial preparation for a FET in a natural cycle (NC) or hormone replacement treatment (HRT). Only blastocysts graded ≥ BL3CC (Gardner scoring) before trophectoderm (TE) biopsy on D5, D6 or D7, which re-expanded within 1-hour post-warming, were considered in the analysis. Participants/materials, setting, methods All warmed blastocysts were transferred after 120 hours of progesterone (P4) exposure. In NC, P4 was administered after ovulation until pregnancy test (PT). For HRT cycles, estradiol was prescribed until endometrial thickness reached ≥6 mm or a trilaminar pattern was seen on which P4 was supplemented until PT. OPR was recorded at 12 weeks by the presence of a gestational sac/s and fetal heartbeat. A multivariate logistic regression model with generalized estimating equation was performed. Main results and the role of chance Women’s mean age differed significantly for FET cycles performed with D5, D6 and D7 euploid blastocysts (33.2±5.6, 34.5±5.3 and 36.1±4.5 years old; P &amp;lt; 0.001) as well as AMH values (ng/mL) (3.6±3.6, 2.9±2.8 and 2.3±1.8; P &amp;lt; 0.001; respectively). OPR with D5 euploid blastocysts was significantly higher than D6 and D7 (55.6%, 44.9% and 10.3%; P &amp;lt; 0.001), however, miscarriage rates did not differ (9.3%, 6.6% and 6.9%; P = 0.201; respectively). Following an adjusted multivariate logistic regression model, the factors associated with a reduced OPR were: D7 FETs (OR: 0.19 [0.06-0.63]; P = 0.006), ICM grade C (OR: 0.29 [0.17-0.48]; P &amp;lt; 0.001) and TE grade C (OR: 0.58 [0.38-0.89]; P = 0.012). Contrary, OPR outcomes were increased in NC compared to HRT cycles (OR: 1.35 [1.06-1.71]; P = 0.013). A sub-analysis showed that advanced maternal age was a risk factor of having a D7 FET cycle (OR: 1.09 [1.01-1.17]; P = 0.025). In patients &amp;gt;38 years, OPR was improved if D7 FET cycles were performed however, this finding was nonsignificant (OR: 2.33 [0.19-29.4], P = 0.510). In patients &amp;lt;38 years, D7 FET cycles were significantly negatively associated with OPR outcomes (OR: 0.07 [0.01-0.54], P = 0.011). Regardless of patient’s age, OPR outcomes with D5/D6 were higher than D7 FETs. Limitations, reasons for caution The current results are based on an observational study including a limited sample size of D7 euploid blastocysts FET cycles. Additionally, live birth rates should be considered in a further analysis to validate the performance of D5 and D6, compared to D7 euploid blastocysts, in both, NC and HRT cycles. Wider implications of the findings Considering age as a risk factor of having delayed grown blastocysts in-vitro, culturing embryos till D7 can be a strategy to increase OPR in patients &amp;gt;38 years old. With an increase in age, patients are more likely to have blastocysts biopsied on D6/D7. OPR outcomes are increased in NC FETs. Trial registration number non-clinical trials

Live birth after transfer of a single euploid vitrified-warmed blastocyst according to standard timing vs. timing as recommended by endometrial receptivity analysis

To determine whether endometrial receptivity analysis (ERA) improves live births in patients with and without a history of unsuccessful frozen embryo transfers (FETs). Retrospective cohort study. Large reproductive center. Patients with and without ERA before euploid single FET were included in the analysis. Subjects in the exposed group underwent ERA and ERA-timed FETs. Subjects in the unexposed group followed a standard protocol FET without ERA. Outcomes were compared between nonreceptive and receptive subjects undergoing an ERA-timed FET and between ERA-timed vs. standard protocol FETs. The primary outcome was a live birth; secondary outcomes were biochemical and clinical pregnancy rates. A total of 307 ERA-timed FETs and 2,284 standard protocol FETs were analyzed. One hundred twenty-five patients (40.7%) were ERA receptive, and 182 (59.3%) were ERA nonreceptive. After adjusting for the number of the previously failed FETs, there was no difference in the proportion of receptive and nonreceptive ERA results. There were no statistically significant differences in live births in patients with ERA-receptive vs. ERA-nonreceptive results (48.8% and 41.7%, respectively; adjusted odds ratio 1.17; 95% CI, 0.97-1.40). There were no statistically significant differences in live births in patients with or without ERA testing results before FET (44.6% and 51.3%, respectively; adjusted odds ratio 0.87; 95% CI, 0.73-1.04). Patients with an increasing number of previous failed euploid FET cycles are not at an increased risk of a displaced window of implantation. Patients categorized as receptive vs. nonreceptive and those without ERA testing results have comparable FET success rates.