P-557 Fresh Transfer with Supernumerary PGT-A Biopsy: The Best of Both Worlds

Study question

What is difference in time to pregnancy for patients between 35-40 years who undergo fresh versus frozen-thawed embryo transfers with or without PGT-A?

Summary answer

Patients undergoing fresh embryo transfer (ET) had a shorter time to pregnancy within the same cycle compared to patients electing for freeze-all cycles.

What is known already

When comparing clinical pregnancy rates following fresh versus frozen-thawed embryo transfers, multiple studies have shown a higher clinical pregnancy rate among frozen-thawed embryo transfers compared to fresh embryo transfers. Particularly for patients over 35 years, there has been a growing national trend towards elective freeze-all cycles, for reasons such as to pursue preimplantation genetic testing for aneuploidy (PGT-A). While PGT-A testing can be effective in reducing miscarriage in patients age 38-40, there is limited studies evaluating time to pregnancy within this population, especially in the context of each passing month’s effect on fertility.

Study design, size, duration

Retrospective review was performed for 697 IVF cycles and 881 transfers from January 2016 – December 2021 at a single academic fertility center in Boston, Massachusetts. Two-tailed t-tests and analysis of variance (ANOVA) were used to compare differences, with p-value less than 0.05 set for statistical significance. All PGT-A testing as performed using a modified FAST-SeqS next generation sequencing method (Invitae, San Francisco, CA).

Participants/materials, setting, methods

Cycle characteristic of patients between 35-40 were categorized to four groups: Fresh ET with PGT-A of supernumerary embryos (82 transfers), Fresh ET without PGT-A (526 transfers), Freeze-all cycle with PGT-A (223 transfers), and Freeze-all cycle without PGT-A (50 transfers). All averages were calculated within one IVF cycle with a single cohort of embryos. Time to pregnancy was calculated in days from day of retrieval to positive serum beta-human chorionic gonadotropin (bHCG).

Main results and the role of chance

Among the 881 transfers, 478 had fresh ETs and 403 had frozen-thawed ETs with or without PGT-A respectively. When comparing fresh and freeze-all cycles, there was no difference in average numbers of transfers performed to achieve a clinical pregnancy (1.27 fresh vs 1.25 freeze-all, p = 0.56). For patients who didn’t elect for PGT-A, there was no difference in number of embryos transferred (1.86 for fresh versus 2.06 for freeze-all, p = 0.54). For patients who elected for PGT-A, the average number of embryos transferred was higher for patients that opted for fresh transfer over freeze-all (1.67 for fresh ET with PGT-A of supernumerary embryos versus 1.24 for freeze-all PGT-A, p = 0.0025). Average days from oocyte retrieval to pregnancy was significantly lower for all fresh ETs (28.8 days for fresh ET without biopsy, 26.6 days for fresh ET with biopsy of supernumerary embryos, p < 0.0001) compared to all freeze-all transfers (110.9 days for freeze-all ET without biopsy, 119.5 days for freeze-all ET with biopsy, p < 0.0001). This delay in time to pregnancy is partially attributed to pending genetic testing results, however, these results usually return in 2-3 weeks, which does not account for the near 3-month delay in time to pregnancy among freeze-all cycles.

Limitations, reasons for caution

These retrospective findings were of all women who achieved pregnancy from one retrieval. These results are not reflective of the patients who needed to undergo multiple cycles to achieve pregnancy, or patients who never achieved pregnancy.

Wider implications of the findings

These findings suggest that PGT-A may be offered to patients > 35 to minimize the number of embryos for transfer. Patients opting for a fresh transfer of an untested embryo and biopsy of supernumerary embryos had a nearly 3-month shorter time to pregnancy than those electing for a freeze-all cycle

Trial registration number

not applicable

O-184 The impact of cryopreserved sperm on Intrauterine Insemination (IUI) outcomes: Is frozen as good as fresh?

Study question

Are the outcomes of IUI cycles [with or without ovarian stimulation (OS)] comparable when frozen instead of fresh-ejaculated sperm is utilized?

Summary answer

Overall, clinical outcomes did not differ significantly between frozen and fresh sperm IUI cycles, although specific subgroups might benefit from fresh sperm utilization.

What is known already

At present, data from animal studies point towards less favorable outcomes with frozen sperm utilization, implicating cryopreservation-induced damages to the cytoskeleton, DNA, and acrosome leading to adverse effects on spermatozoa’s motility, viability, and ability to fuse with the oocyte. Assisted Reproductive Technology (ART) data, mostly focusing on severe male factor infertility diagnoses, suggest no major differences between in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles utilizing frozen over fresh sperm, often surgically extracted. Nevertheless, contemporary data from IUI(±OS) cycles are still scarce.

Study design, size, duration

Data from 5335 IUI(±OS) cycles (time-period: 01/2004-12/2021) from a large academic fertility center were retrospectively reviewed. Cycles were stratified in two groups based on utilization of frozen instead of fresh-ejaculated sperm for the IUI [FROZEN (n = 1871, all infertility diagnoses), and FRESH (n = 3464, idiopathic infertility diagnosis only), respectively]. Cycle outcomes were compared between groups.

Participants/materials, setting, methods

Participants: women seeking IUI (±OS) treatments.

Outcome Measures: HCG-positivity, clinical pregnancy (CP), spontaneous abortion (SAB) rates. Initial analysis included all cycles irrespective of OS regimen.  Cycles were then stratified by OS regimen into three subgroups [injectable gonadotropins, oral medications (OM): clomiphene-citrate and letrozole, and unstimulated/natural]. Odds ratios (OR) for all relevant outcomes were calculated utilizing logistic regression and adjusted for maternal age, day-3 FSH, and OS regimen. Time-to-pregnancy and first-cycle only analyses were also performed.

Main results and the role of chance

Unadjusted HCG-positivity, and CP were lower in the FROZEN compared to the FRESH group (12.2% vs. 15.6%, p < 0.001; 9.4% vs. 13.0%, p<.001, respectively), which persisted only among OM after stratification (9.9% vs. 14.2% HCG-positivity, p=.030; 8.1% vs. 11.8% CPR, p=.041, for FROZEN compared to FRESH, respectively).

Among all cycles, adjOR(95%CI) for HCG-positivity and CP were respectively: 0.75(0.56-1.02), and 0.77(0.57-1.03), ref: FRESH). Following stratification by OS regimen, adjOR(95%CI) for HCG-positivity and CP showed no difference between groups among gonadotropin and natural cycles but favored the FRESH group in OM cycles [HCG-positivity: 0.55(0.30-0.99); CP: 0.49(0.25-0.95), ref.: FRESH]. SAB odds did not differ between groups among OM and natural cycles but were lower in the FROZEN compared to FRESH group among gonadotropin cycles [adjOR(95%CI): 0.13(0.02-0.98), ref.: FRESH]. However, regarding the latter comparison, numbers were small and the 95%CI wide.  When analysis was limited to first-cycles only and further stratified by OS regimen, the previously noted differences in CP and SAB odds no longer existed within the OS subgroups.

Nevetheless, time-to-conception was slightly longer in the FROZEN compared to the FRESH group (3.84 vs. 2.58 cycles, p<.001).

Limitations, reasons for caution

Study is limited by its retrospective nature. The two groups differed somewhat in age, infertility diagnosis, utilized OS regimen, and as expected in total motile sperm counts. Despite the less favorable characteristics of the FROZEN group, no detrimental effect of sperm cryopreservation on IUI outcomes was noted.

Wider implications of the findings

Our study, the largest to date, showed no significant difference in IUI outcomes between cycles utilizing frozen instead of fresh-ejaculated sperm. Although, specific subgroups might benefit from fresh sperm utilization and time-to-pregnancy might be shorter with fresh over frozen sperm, patients should be counselled about the non-inferiority of frozen sperm.

Trial registration number

Not applicable

P-342 The impact of Clomiphene Citrate (CC) on the endometrium in comparison to gonadotropins (Gn) in intrauterine-insemination treatments (IUI): Is it thinner and does it matter?

Study question

Utilizing patients as their own controls, does endometrial thickness (EMT) differ between CC/IUI and Gn/IUI? Does EMT differ between CC-cycles with and without associated conception?

Summary answer

Within-patient, CC resulted in thinner EMT compared to Gn. CC-cycles associated with conception compared to the ones without it, had thicker endometria.

What is known already

CC, unlike gonadotropins, may have an anti-estrogenic effect on the endometrium. Concerns exist that the thinning of the endometrium might be associated with altered endometrial development and receptivity. However, available data in CC cycles remain inconsistent, probably due to patient and protocol heterogeneity. Currently, it remains unclear whether CC treatments produce a thinner endometrium, compared to gonadotropins, in the same patient. Furthermore, it is uncertain whether such a difference, if one exists, has a consequential effect on IUI cycle outcomes.

Study design, size, duration

Design: retrospective.

Duration: 1/2004-9/2021

Cohort 1 utilized women as their own controls to evaluate CC’s impact on the endometrium and included all cycles from women who sought fertility treatments and initially underwent CC/IUI (CC1, n = 1252) followed by Gn/IUI (Gn1, n = 1307).

Cohort 2 included all cycles from women seeking fertility treatments at the same center that conceived following CC/IUI treatments (CC2, n = 686).

EMT was compared between groups (CC1 vs. Gn1, CC1 vs. CC2).

Participants/materials, setting, methods

Outcome measures:

Primary: EMT (mm).

Secondary: HCG-positivity (pos-HCGR), clinical pregnancy (CPR), and spontaneous abortion rates (SABR).

Statistics:

Regression analysis was used to calculate Odds Ratios (OR) with associated 95% confidence intervals (95%CI), adjusting for potential confounders [maternal age, Body Mass Index (BMI), prior parity, day of EMT measurement relative to trigger). Generalized estimating equations (GEE) model were utilized to account for multiple cycles per patient. P < 0.05 was considered significant.

Main results and the role of chance

In cohort 1, despite CC1 exhibiting non-inferior ovarian response compared to Gn1 (as assessed by preovulatory follicular number), EMT was significantly thinner in CC1 compared to Gn1 [Median(IQR): 7.0(5.7-8.3) vs. 8.9(7.4-10.0), p<.001]. When CC1 was compared to CC2 (CC conceiving), EMT was also thinner [Median(IQR): 7.0(5.7-8.3) vs. 7.5(6.2-9.0), for CC1 vs. CC2, respectively, p<.001]. A higher percentage of CC1 compared to Gn1 cycles resulted in EMT≤7mm (48.9% vs. 16.7% , for CC1 vs. Gn, respectively; p<.001). Most subsequent Gn cycles (82.8%), in the same women, resulted in thicker EMT compared to CC1. AdjOR, in generalized linear mixed models, suggested that CC2 when compared to CC1 cycles had thicker EMT [adjOR(95%CI): 1.81, (1.41,2.35), p<.001].

Interestingly, clinical pregnancies were observed even when EMT was ≤4mm in both CC2 and Gn1 groups and SABR did not differ between cycles with EMT≤4mm and the ones with thicker EMT (2.5% vs. 11.5%, p=.258, in CC2; 0% and 12.3%, p=.544, in Gn1; SABR EMT ≤4 vs. 4 mm, respectively). GEE models suggested an association between EMT and CPR in CC cycles (CC1&CC2), [adjOR(95%CI): 1.12(1.07,1.18), p<.001)] while in Gn1, no such association was observed.

Limitations, reasons for caution

Our study was limited by its retrospective design. Reflecting our selection criterion, in cohort 1, most CC cycles did not result in pregnancy, restricting relevant comparisons. Number of cycles resulting in EMT ≤7mm, and particularly ≤4mm, was limited, and consequently respective results should be interpreted cautiously.

Wider implications of the findings

Utilizing patients as their own controls, we showed that CC compared to gonadotropins resulted in thinner endometrium. Given comparable follicular response, and potentially estradiol levels, thinner endometrium might have resulted from CC’s anti-estrogenic effect. Furthermore, patients conceiving on CC had a thicker endometrium compared to the ones that did not.

Trial registration number

NA

P-434 Is there an association between pre-ovulatory estradiol levels and placental pathology of singleton livebirths conceived with gonadotropins/intrauterine insemination (Gn/IUI) treatments?

Study question

Is pre-ovulatory estradiol level associated with placental weight (PW) and abnormality rates (PAR) in singleton livebirths resulting from gonadotropins/intrauterine insemination (Gn/IUI) treatments?

Summary answer

In Gn/IUI-conceived, singleton-livebirths with available placental pathology, an association was noted between preovulatory estradiol levels and PW, but not between estradiol and PAR.

What is known already

Data suggest an association between ART and placental-mediated pregnancy complications, as well as increased rates of placental pathology. Supraphysiologic levels of preovulatory estradiol have been implicated in abnormal placentation. Whether such an effect is noted in Gn/IUI treatments, where levels of estradiol are lower, nevertheless supraphysiologic, remains unknown.

Study design, size, duration

We retrospectively reviewed data from 560 Gn/IUI-conceived, singleton-livebirths (1/2004-1/2021) recruited from a large academic fertility center. Placental pathology information was available from 218 cycles. These cycles were stratified by pre-ovulatory estradiol levels in quartiles [Q1(lower)-Q4 (higher)]. PW [grams & percentiles (%iles)], and rates of placental abnormalities (classified as anatomic, inflammatory, infectious, and vascular/thrombotic) were compared between groups.

Participants/materials, setting, methods

Participants: Women with Gn/IUI-conceived, singleton-livebirths with available placental pathology.

Outcome Measures: PW and PAR.

Statistics: Regression analysis was utilized to estimate the association of pre-ovulatory estradiol %iles with PW and PAR, adjusting for potential confounders (PW: maternal and gestational age, BMI, infertility diagnosis, medical complications, infant gender; PAR: maternal and gestational age, BMI, race). Adjusted Odds Ratios (OR) with 95%CI were calculated for the latter.

Main results and the role of chance

Mean PW(±SD) in grams were 477.3(±124.1), 445.9(±107.4), 451.2(±113.9), and 438.9(±107.0) in Q1 through Q4 (p=.368). Small placentas (≤10thPW %ile) accounted for more than a third of the total in all estradiol quartiles (37.5%, 49.2%, 37.5%, and 42.2%, p=.539, Q1-Q4, respectively). Similarly, increasingly higher percentages of placentas ≤25th PW %ile were noted with increasing estradiol quartiles (47.9%, 57.6%, 62.5% and 64.5%, in Q1-Q4 respectively, p=.347). After adjusting for potential confounders, we noted a mean 13.7 grams decrease in PW between each subsequent estradiol quartile [ adjβ-coeff (95%CI): -13.7(-27.7-0.3), p=.055]. When estradiol levels were analyzed as a continuous variable, an inverse association with PW [ adjβ-coeff (95%CI): -0.08 (-0.16-(-0.01)), p=.026] was noted. Adjusted ORs for small placenta did not differ between estradiol quartiles or when estradiol was analyzed as a continuous variable [adjORs(95%CI): 1.73(0.74-4.07), 1.10(0.47-2.55), 1.81(0.69-4.72), for Q2-Q4, Q1 as ref.; 1.001(1.000-1.003), p=.167; respectively].

There was no significant association between placental abnormality rates (PAR) and estradiol, either before or after adjustment [adjORs(95%CI): i) Anatomic : 1.16(0.49-2.74), 1.52(0.65-3.59), and 1.17(0.45-3.02); ii) Inflammatory : 0.40(0.13-1.25), 0.79(0.28-2.17), and 1.25(0.42-3.73); iii) Infectious : 0.89(0.35-2.25), 1.67(0.68-4.13), and 0.58(0.20-1.67); iv) Vascular/thrombotic : 0.88(0.37-2.08), 1.87(0.80-4.41), and 0.95(0.36-2.49); for Q2-Q4 vs. Q1].

Limitations, reasons for caution

There are several limitations, including the retrospective design, possible selection bias resulting from the decision to obtain placental pathology. Nonetheless, birth weights did not differ between those with and without placental pathology. Estradiol levels, albeit supraphysiologic, are much lower than those in ART and differences might be masked.

Wider implications of the findings

In Gn/IUI-conceived, singleton-livebirths with available placental pathology, an association was noted between preovulatory estradiol levels and placental weight, but not between estradiol and the rate of specific placental abnormalities (PAR). Since estradiol levels are lower than those observed in ART, an association might have been missed.

Trial registration number

not applicable

O-299 Analyzing the impact of simple wash versus density gradient sperm preparations on intrauterine insemination outcomes. Is the cost-effective and time-efficient option just as good?

Study question

How do different sperm preparations, such as simple-wash (SW) and density-gradient (DG), impact intrauterine insemination (IUI) outcomes among women seeking fertility treatments?

Summary answer

Using a population from a large, academic medical center, this study discerned no differences in pregnancy outcomes between SW and DG sperm preparations.

What is known already

IUI with or without ovulation induction (OI) is often a first-line treatment among couples seeking fertility services. SW and DG are two common methods used to prepare sperm for IUI. In comparison to its latter counterpart, the SW technique is lesser-used, yet is more time-efficient, and cost-effective due to its utilization of only a single centrifugation step. Since the impact of sperm preparation techniques on the post-processing sperm yield and its parameters varies by the method used, the cycle outcomes might differ as well. However, limited data exists on various sperm preparations’ impact on IUI clinical outcomes.

Study design, size, duration

Data from 3378 IUI+OI cycles (from 1503 women of all diagnoses seeking IUI with fresh-ejaculated sperm) that took place at a large academic fertility center between 9/2014 and 3/2021 were retrospectively reviewed. Cycles were either unstimulated (natural) or stimulated with either oral OI agents (clomiphene-citrate & letrozole) or gonadotropins. Cycles were divided in two groups based on sperm preparation technique: SW (n = 1691) and DG (n = 1687) and outcomes were compared between them.

Participants/materials, setting, methods

Sperm preparation: SW semen were mixed in 10ml MHM (FujiFilm) and centrifuged for 10min. DG semen were layered over 45:90 gradient of Isolate (FujiFilm), centrifuged for 20min, and washed twice (10min) in 10ml MHM.

Outcome measures: hCG-positivity (posHCGR), clinical pregnancy (CPR), spontaneous abortion (SABR), and livebirth rates/cycle (LBR).

Statistics: Logistic regression with Odds Ratios (OR) adjusted for both partners’ ages, day-3 FSH, stimulation, and sperm score (poor, fair, good, excellent). Sub-analysis limited cohort to first-cycles only.  

Main results and the role of chance

Groups were comparable in patient [age (maternal, paternal), BMI, day-3 FSH, infertility diagnosis], and cycle characteristics [follicular response (measured as number of preovulatory follicles), and endometrial thickness]. Preprocessing sperm parameters differed slightly with higher mean sperm concentrations and lower total motility among SW cycles (75.3 + 57.0 vs. 71.0 + 51.3 million, p = 0.02; 48.6 + 19.6 vs. 52.5 + 20.2, p < 0.001, for SW and DG, respectively). posHCGR, CPR, SABR, and LBR per cycle did not differ between groups (15.8% vs. 15.4%, p = 0.76;13.7% vs. 13.2%, p = 0.62;18.1% vs. 18.5%, p = 0.93; 9.5 vs. 8.9%, p = 0.56; for SW and DG, respectively).

Odds for posHCG, CP, SAB, or LB did not differ between groups [adjOR(95%CI): 1.05(0.87-1.26), p = 0.65; 1.10(0.67-1.83), p = 0.71; 0.98(0.60-1.60), p = 0.94; 1.08(0.85-1.37), p = 0.66, respectively]. When cycles were stratified by type of ovarian stimulation, rather than adjusted for it, no difference was seen in any of the clinical outcomes within individual strata{adjOR(95%CI): [Oral OI: 1.00(0.74-1.37), p = 0.98; 1.78(0.68-4.61), p = 0.25; 0.97(0.40-2.38), p = 0.95; 1.05(0.72-1.53), p = 0.81], [Gonadotropins: 0.99(0.78-1.28), p = 0.96; 0.93(0.49-1.77), p = 0.83; 0.97(0.52-1.80), p = 0.96; 1.03(0.75-1.41), p = 0.87], [Natural: 2.36(0.97-5.76), p = 0.06; 0.08(0.001-6.84), p = 0.26; 0.20(0.003-11.02), p = 0.43; 2.52(0.63-10.00), p = 0.19], for posHCG, CP, SAB, and LB, respectively}. Similarly, no difference was seen in any of the clinical outcomes when cycles were stratified by sperm score or when analysis was limited to first-cycles only.

Limitations, reasons for caution

LBR were calculated excluding pregnancies with no information after discharge to obstetrics (approximately 16%). Although not significant, there might be minor variations in individual provider’s practices between time frames in which these techniques were implemented.

Wider implications of the findings

SW is a much simpler, time-efficient, and cost-effective sperm processing technique for IUI compared to DG, however remains infrequently utilized. Adoption of SW, over DG, could yield comparable clinical efficacy, yet optimize teamwork flow and lower healthcare costs, due to its non-labor-intensive and inexpensive nature.

Trial registration number

not applicable

P-294 Use of Artificial Intelligence to Assess the Effects of Assisted Hatching on Embryo Development and Implantation Potential

Study question

Does the use of laser-assisted hatching (AH) on cleavage stage embryos affect in vitro preimplantation embryo development or implantation potential?

Summary answer

There is no difference in blastocyst conversion rate or implantation potential of embryos following AH at the cleavage stage for patients under age 35 years.

What is known already

Laser-AH is the process of creating an opening within the zona pellucida on cleavage stage embryos to facilitate biopsy of trophectoderm cells for preimplantation genetic testing (PGT). Studies have shown that PGT for aneuploidy (PGT-A) in patients under 35 years have reduced pregnancy rates compared to those not undergoing biopsy. This is attributed to the additional micromanipulation events involved with PGT-A may decrease the viability of embryos and compromise their implantation potential. We aimed to objectively compare the impact of AH on embryo development using an artificial intelligence (AI)-algorithm trained to assess embryo quality and predict developmental fate.

Study design, size, duration

A retrospective dataset from patients under 35 years was generated from two timepoints: cleavage stage embryos immediately before AH between 60-64 hours post insemination (hpi); and blastocyst stage embryos between 110-115 hpi prior to transfer or vitrification. Time-lapse imaging was obtained using the EmbryoScope (Vitrolife). Cleavage stage embryo images were used to train a convolutional neural networks (CNN) to predict and classify the development and implantation potential of cleavage and blastocyst stage embryos.

Participants/materials, setting, methods

Time-lapse images were collected for 1444 cleavage stage embryos spanning 189 in vitro fertilization (IVF) cycles between January 2014 – December 2021 at a single academic fertility center in Boston. Embryos were categorized into two groups: Day 3 embryos with AH (D3+AH) and without AH (D3-No AH). Each patient had a single blastocyst embryo transfer with a known outcome. Two-tailed t-tests were used to compare differences, with p-value less than 0.05 set for statistical significance.

Main results and the role of chance

The dataset included 1035 embryos with AH (D3+AH) and 409 embryos without AH (D3-No AH). There were no differences in AI-predicted blastocyst development between Day 3 embryos with AH and without AH (64.1% vs 64.1%) or AI-predicted high quality blastocyst development rate between these two groups (43.8% vs 40.8%), respectively. On Day 5 there were no differences in the AI-categorization of embryos at the blastocyst stage between embryos with or without AH (62.3% vs 62.5%) or AI-categorization of high-quality blastocyst development (45.2% vs 41.8%), respectively. AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (61.1% vs 69.9%). When stratifying to only the embryos transferred, there were no differences in the AI-predicted blastocyst development between Day 3 embryos with AH and without AH (96.0% vs 97.1%) or in the AI-predicted high quality blastocyst development rate between these two groups (72.0% vs 82.7%). AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (72.0% vs 69.0%). These results correspond with the true clinical pregnancy rate between the AH and Non-AH groups (68.0% vs 61.9%, p = 0.44).

Limitations, reasons for caution

These retrospective findings were of patients who had time-lapse imaging of cleavage stage and blastocysts available. Additionally, we focused on high prognosis patients that were eligible for single blastocyst stage embryo transfer. Clinical pregnancy rate was examined, not spontaneous abortion or live birth rates.

Wider implications of the findings

Utilization of AI technology allows for more objective and standardized methods for examining the impact of laboratory procedures on the developmental fate of embryos. This study demonstrated the safety of utilizing laser-assisted hatching on embryo development within this study population.

Trial registration number

None

P-426 Placental pathology following Intrauterine Insemination (IUI) with or without Ovarian Stimulation (OS)

Study question

Do placental weight percentiles (PW %iles) and abnormality rates (PAR) differ in singleton-livebirths following IUI with or without OS [oral medications (OM), and injectable gonadotropins]?

Summary answer

Following singleton-livebirths, PW did not differ between groups, albeit over half of placentas were ≤25th%ile. Placental anatomic abnormalities were more often seen in OM cycles.

What is known already

ART data suggest a possible association between stimulation-induced supraphysiologic estradiol levels and increased risk of placental abnormalities, as well as subsequent placental-mediated pregnancy complications, such as preeclampsia. Whether there is an association between OS protocols for IUI and placental pathology remains unknown.

Study design, size, duration

Data from 975 IUI(±OS) cycles resulting in singleton livebirths at a large academic fertility center between 01/2004 and 01/2021, were retrospectively reviewed. In 386 cycles a full placental pathologic examination was available. Placentas were stratified by OS regimen into three groups: gonadotropins (n = 222), OM [Clomiphene Citrate (CC)/Letrozole (LTZ); n = 129], and unstimulated / natural (n = 35). PW and PAR were compared between groups.

Participants/materials, setting, methods

Participants: Women delivering a singleton liveborn following IUI(±OS) treatments with placental pathology available.

Outcome Measures: PW (grs & %iles), and PAR (classified as anatomic, inflammatory, infectious, and vascular/thrombotic).

Statistics: Regression analysis was utilized to compare PW and PAR between groups, adjusting for potential confounders (PW: maternal and gestational age, BMI, infertility diagnosis, medical complications, infant gender; PAR: maternal and gestational age, BMI, race). Adjusted Odds Ratios (adjOR, 95%CI) were calculated for the latter.

Main results and the role of chance

Mean(±STDEV) PW (grs) were 451.7(±113.3), 449.2(±102.4), and 481.8(±99.8), for the gonadotropins, OM, and natural groups, respectively. Interestingly, over half of the placentas in all three groups were ≤25th %ile (58.6%, 56.1%, and 52.9%, for gonadotropins, OM, and natural, respectively, p=.249), while 41.8%, 46.4%, and 38.2% were below the 10th %ile (for gonadotropins, OM, and natural, respectively, p=.598). Adjusted PW differences, and adjOR for small placenta (≤10th %ile) did not differ between groups [PW OR(95%CI): 5.6(-17.9-29.2), -28.1(-71.4-15.2), -11.7(-52.6-29.3); small placenta OR(95%CI): 1.04(0.62-1.76); 1.27(0.40-4.01), and 0.96(0.34-2.74) for OM vs. gonadotropins, OM vs. natural, and gonadotropins vs. natural, latter as ref. ].

Regarding PAR, anatomic(43.7%, 52.7%, and 40%, p=.192), inflammatory(20.7%, 27.1%, and 20%, p=.354), infectious(32.9%, 33.3%, and 31.4%, p=.978), and vascular/thrombotic(42.3%, 41.9%, and 42.9%, p=.993) abnormalities rates did not differ between gonadotropins, OM, and natural, respectively. AdjORs(95%CI) for inflammatory, infectious, and vascular/thrombotic abnormalities did not differ significantly between groups. However, anatomic abnormalities were more frequent among OM compared to gonadotropin and natural cycles [adjOR(95%CI): 1.76(1.06-2.91), p=.028, gonadotropins as ref.; 2.52(1.05-6.05), p=.038, natural as ref.].

Limitations, reasons for caution

This study is limited by its retrospective nature. Unfortunately, placental pathology was available only in conceptions clearly identified as resulting from IUI(±OS) treatments. However, birth weights did not differ between those with and without available placental pathology. Natural/IUI cycles were limited in numbers not allowing meaningful conclusions.

Wider implications of the findings

Between IUI-conceived, singleton-livebirths with available placental pathology, mean PW did not differ significantly. However, a higher-than-expected percent of placentas were below the expected %iles, suggesting that IUI(±OS) might be associated with altered placental growth. Placental anatomic abnormalities were more common among OM cycles, compared to gonadotropins, and n atural IUI cycles.

Trial registration number

Not applicable

O-125 Development of an artificial intelligence embryo witnessing system to accurately track and identify patient specific embryos in a human IVF laboratory

Study question

Can convolutional neural networks (CNN) be used as a witnessing system to accurately track and identify patient specific embryos at the cleavage stage of development?

Summary answer

We developed the first artificial intelligence driven witnessing system to accurately track cleavage and blastocyst stage embryos in a human ART laboratory.

What is known already

There are reports of human errors in embryo tracking that have led to the births of children with different genetic makeup than their birth parents. Clinical practices rely on manual identification, barcodes or radio-frequency identification technology to track embryos. These systems are designed to track culture dishes but are unable to monitor developing embryos within the dish to help ensure an error-free patient match. Previously, we developed an AI witnessing system to track blastocysts with 100% accuracy. The goal of this study was to determine whether an AI witnessing system could be developed that accurately tracks cleavage stage embryos.

Study design, size, duration

A pre-developed deep neural network technology was first trained and tested on 4944 embryos images. The algorithm processed embryo images for each patient and produced a unique key that was associated with the patient ID at 60 hpi, which formed our library. When the algorithm evaluated embryos at 64 hpi it generated another key that was matched with the patient’s unique key available in the library.

Participants/materials, setting, methods

A total of 3068 embryos from 412 patients were examined by the CNN at both 60 hpi and 64 hpi. These timepoints were chosen as they reflect the time our laboratory evaluates Day 3 embryos (60 hpi) and the time we move them to another dish and prepare them for transfer (64 hpi). The patient cohorts ranged from 3-12 embryos per patient.

Main results and the role of chance

The accuracy of the CNN in correctly matching the patient identification with the patient embryo cohort was 100% (CI: 99.1% to 100.0%, n = 412).

Limitations, reasons for caution

Limitations of this study include that all embryos were imaged under identical conditions and within the same EmbryoScope. Additionally, this study only examined fresh Day 3 embryos cultured over a span of 4 hours. Future studies should include images of fresh and frozen/thawed embryos captured using different imaging systems.

Wider implications of the findings

This study describes the first artificial intelligence-based approach for cleavage stage embryo tracking and patient specimen identification in the IVF laboratory. This technology offers a robust witnessing step based on unique morphological features that are specific to each individual embryo.

Trial registration number

This work was partially supported by the Brigham Precision Medicine Developmental Award (Brigham Precision Medicine Program, Brigham and Women’s Hospital), Partners Innovation Discovery Grant (Partners Healthcare), and R01AI118502, and R01AI138800.

P–034 Social distancing protocol changes during the COVID–19 pandemic; the effect of at-home semen collection on intrauterine insemination outcomes

Study question

How have the coronavirus 2019 (COVID–19)-driven changes in semen collection protocols, from on-site to at-home collection, impacted intrauterine insemination (IUI) cycle outcomes?

Summary answer

Our data suggest that at-home semen collection within 2 hours of processing does not negatively impact semen parameters and IUI pregnancy outcomes. What is known already: There are mixed reports regarding the effect of at-home semen collection on IUI outcomes. In a study of 633 cycles, no differences in semen parameters or pregnancy rates were observed between home and clinic collections¹. Conversely, in a smaller cohort, at-home collection was associated with worse pregnancy outcomes when IUI was coupled with gonadotropin stimulation, but not when coupled with clomiphene². We previously reported no differences in semen parameters and in-vitro fertilization (IVF) embryo transfer outcomes, when cycles using semen collected at-home were compared to cycles with on-site collection³. However, such findings cannot necessarily be extended to the IUI setting.

Study design, size, duration

This is a retrospective cohort study of all 529 IUI cycles that took place in 2020 at an academic fertility center. Semen collected at the “clinic” was used for 143 cycles before the COVID–19 pandemic, and “at-home” collected specimens were used for the 386 cycles following the revised semen collection protocol. Participants/materials, setting, methods: Prior to the COVID–19 pandemic, semen was collected at our “clinic” and processed within ∼30 minutes. Post-COVID, in order to maintain social distancing, semen was collected “at-home”, at an IUI-approved cup, and transported to our center within 2 hours, while maintained to room temperature. Logistic regression models were performed to evaluate the effect of “at-home” collection on achieving pregnancy (positive pregnancy test-PPT) and clinical pregnancy (sonographic confirmation-CP), adjusting for age and anti-Mullerian hormone (AMH).

Main results and the role of chance

The mean age (SD) (years) of the female partner was 35.4 (4.2) vs. 35.4 (4.4) (p = 0.978) and of the male partner 36.6 (4.4) vs. 37.1 (p = 0.328) for the “clinic” vs. “at-home” groups, respectively. There were no significant differences in day–3 follicle stimulating hormone and AMH. In both groups the most common diagnoses were idiopathic and combined factors infertility (27.3% and 18.9% & 24.1% and 25.1%, respectively for the “clinic” & “at-home” groups, p = 0.376). Similarly, there were no differences regarding ovarian stimulation, and gonadotropins were the most common medication used in both groups (“clinic”: 44.1% vs. “at-home”: 39.4%, p = 0.775). Semen analysis parameters (volume, motility, forward progression, total motile count) were comparable between the 2 groups, with the exception of concentration (mil/ml) which was higher with “at-home” collection [66.1 (45.0) vs. 81.1 (63.0), p = 0.009].

In unadjusted models, “at-home” collection had no significant effect on the odds for a PPT [OR (95%CI): 0.691 (0.427–1.119), p = 0.133] or CP [0.751 (0.447–1.263), p = 0.281]. These results persisted even when adjusting for maternal age and AMH: PPT [0.708 (0.435–1.153), p = 0.165] and CP [0.773 (0.455–1.312), p = 0.340]. When sub-analysis was performed within the different medication groups, the above findings persisted for both gonadotropin and oral medication cycles.

Limitations, reasons for caution

The limitations of the study include its retrospective design and the absence of livebirth data, given the limited follow up period. However, regarding the latter, one can use the ongoing clinical pregnancy rate as an accurate estimate of livebirth.

Wider implications of the findings: At-home semen collection within 2 hours of processing did not negatively impact semen analysis parameters or pregnancy outcomes following IUI. These data constitute an important addition to the current limited literature on the subject and provides an additional level of safety for our patients and staff during the COVID–19 crisis.

Trial registration number

Not applicable

The impact of male factor infertility on early and late morphokinetic parameters: a retrospective analysis of 4126 time-lapse monitored embryos

STUDY QUESTION

Is there an effect of male factor infertility (MFI) on either early or late morphokinetic parameters obtained during embryonic culture to blastocyst stage in a time-lapse imaging (TLI) incubator?

SUMMARY ANSWER

Neither mild nor severe MFI had an impact on overall time to blastocyst or duration of individual cleavage stages in the total embryo population.

WHAT IS KNOWN ALREADY

Prior studies have suggested that paternal DNA and sperm quality affect embryo morphokinetic parameters, but the impact of MFI is not fully understood.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study, at a major academic fertility centre, included 536 couples (women, ≤44 years of age) undergoing IVF between September 2013 and September 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data from 4126 embryos cultured to the blastocyst stage in a TLI-monitored incubator were retrospectively reviewed. Embryos derived from the sperm of men with MFI were compared with those derived from patients with other infertility diagnoses. Generalized fixed and random effects models, t-test and χ2 were used as appropriate.

MAIN RESULTS AND THE ROLE OF CHANCE

Couples with MFI had a higher rate of ICSI utilization and fewer usable embryos on average, and the men were older compared with couples with other diagnoses. Additionally, the women in MFI couples were younger and had higher antral follicle counts (AFCs) and higher anti-Müllerian hormone (AMH) levels compared with the other women undergoing IVF. When controlling for maternal and paternal ages, AMH and fertilization method (conventional IVF versus ICSI), neither mild nor severe MFI affected duration of individual cleavage stages or overall time to the blastocyst stage, when all or only usable embryos were examined (coefficient 0.44 hours in all embryos, P = 0.57; coefficient 0.39 hours in usable embryos, P = 0.60). Whether the sperm was surgically extracted similarly had no significant effect on embryo morphokinetic parameters. When the fertilization method was assessed independently, ICSI lengthened the overall time to blastocyst stage by 1.66 hours (P = 0.03) on average, primarily due to an increase in duration of the time from 5-cell embryo stage to early blastulation (P5SB).

LIMITATIONS, REASONS FOR CAUTION

This large cohort study avoided embryo selection bias due to random assignment of embryos to the TLI incubators. However, our findings may not be generalizable to groups under-represented in our clinic population. Future studies should also evaluate the impact of male hormonal status and detailed sperm morphology, such as head versus flagellum defects, on embryo morphokinetic development.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that the fertilization method rather than MFI per se impacts time to early blastulation. The clinical implications of this effect on embryo development warrant further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

There were no sources of funding for this study. There are no competing interests.

TRIAL REGISTRATION NUMBER

N/A

Correction to: Abstracts : 31st European Congress of Pathology

The name of the co-author of E-PS-07-008 (page S294) was presented as 'S. Despina' instead of 'D. Sgouridi' in the authorship group The name has been corrected in the authorship group shown above.

The effect of day 2 versus day 3 embryo transfer on early pregnancy outcomes in women with a low yield of fertilized oocytes

PURPOSE

To evaluate the differences in implantation and pregnancy rates when embryo transfer occurs on D2 versus D3 in women with a low yield of fertilized oocytes.

METHODS

A total of 156 IVF/ICSI cycles from 141 women at an academic fertility center were analyzed in a retrospective fashion. Women with a low number of fertilized oocytes (≤ 2 two pronuclei (2PN) stage zygotes) who had their fresh embryo transfer on D2 or D3 were included in the study. Positive pregnancy test per IVF cycle (PPT), clinical pregnancy rate (CPR), spontaneous abortion rate (SABR), and implantation rate (IMPR) were the main outcome measures assessed. Mann-Whitney U test and χ² test were used as appropriate. A generalized linear mixed effect model adjusted for relevant covariates was conducted. P < 0.05 was considered significant.

RESULTS

Patients having their embryo transfer on D2, when compared to those who had a D3 embryo transfer, experienced similar PPT [30.8 vs. 28.2%, respectively; adjusted OR (95%CI): 0.49 (0.16, 1.52)], CPR [26.9 vs. 25.6%, respectively; adjusted OR (95%CI): 0.44 (0.12, 1.67)], and IMPR [17.3 vs. 16.7%, respectively; adjusted β (95%CI) - 5.6% (- 15.0, 3.9)].

CONCLUSION

Our findings suggest that transferring embryos on D2 versus D3 in women with a limited number of 2PN stage zygotes does not affect early pregnancy outcomes. These results indicate that there can be some flexibility in scheduling the day of transfer at the convenience of both the patient and the center.

Factors affecting chromatin stability of bovine spermatozoa

The structural stability of transcriptionally inert paternal chromatin is of vital importance for the fertilization process and early embryonic development. Accordingly, a series of eight experiments were conducted during a 7-month period to investigate: (1) effects of bull breed, individuality, successive ejaculations, semen quality characteristics (SQC), semen dilution rates and hypothermic storage of semen in a Tris-egg yolk extender on incidence of sperm nuclear chromatin instability (NCI), and (2) effects of the interaction between variation of NCI within a frozen ejaculate and variation of oocytes quality due to maturation time and/or season on the efficiency of in vitro embryo production (IVEP). Semen samples were collected once a week from six bulls using an AV and only ejaculates (n=220) of >0.30x10(9) sperm/ml and >or=60% motility were used. NCI was measured by: (1) detection of lysine-rich histones in sperm chromatin using aniline blue staining, (2) sperm susceptibility to acid-induced nuclear DNA denaturation in situ using acridine orange test, and (3) sperm susceptibility to nuclear chromatin decondensation (NCD). Bovine oocytes (n=695) were matured in vitro for 18 or 24 h, fertilized after sperm selection through a swim-up procedure and cultured for 72 h. The results showed that the 2nd ejaculates were superior to the 1st ones with respect to chromatin stability. Dilution of semen to 49.67+/-8.56x10(6) sperm/ml (1:19) decreased resistance of sperm to NCD. Cooling of semen had no significant effect on chromatin stability. Cryopreservation of semen augmented sperm vulnerability to DNA denaturation. Improvement of SQC (semen volume, sperm motility, velocity, viability and morphological normalcy) was generally concomitant with increase of sperm resistance to NCI. While Blonde d'Aquitaine bulls had a resistance to NCD higher than Limousine bulls in fresh semen, the former showed a greater susceptibility to DNA denaturation than the latter in cooled semen. Individuality significantly influenced NCI. The variability of NCI within a frozen ejaculate affected efficiency of IVEP. Significant negative correlations were observed between incidence of NCI and both fertilization rate and developmental capacity of embryos after maturation of oocytes for 18 h. The significant variation in IVEP traits due to season was independent of the effect of sperm chromatin instability.

293 EFFECT OF GUAIAZULENE ON IN VITRO BOVINE EMBRYO PRODUCTION

The substrates used in in vitro embryo production (IVP) mimic the in vivo fluids in which oocytes mature, oocytes are fertilized, and the early embryos develop (follicular and oviductal fluid). It is well established that oxidative stress negatively affects in vitro culture (IVC) outcomes. Guaiazulene (G) is a component of chamomile species oil with known antioxidant properties. In the present study, all IVP media were modified by the addition of G solutions so that the former exhibited a total protection against induced lipid peroxidation (TPaLP) similar to that of the respective in vivo environment. The IVP outcomes were then compared between G-processed and control oocytes. Bovine preovulatory follicular (BF) and oviductal (BO) fluid samples were collected from 10 Holstein 4- to 5-year-old cows in estrus. TPaLP was assessed according to the samples&apos; ability to inhibit rat hepatic microsomal lipid peroxidation, by determination of the 2-thiobarbituric acid reactive material. TPaLP (mean % � SEM) of the BF and BO were 70.63 � 10.03 and 16.33 � 4.33, respectively, whereas those of the IVP [in vitro-matured (IVM), in vitro-fertilized (IVF), and IVC] media were lower (17.94 � 1.66, -1.82 � 0.78, and 14.57 � 1.26, respectively). TPaLP of the 0.1 mM G-modified IVP medium increased to 67.2 � 5.85, 19.98 � 2.49, and 69.19 � 6.22, respectively. A total of 2041 class A oocytes were used. The proportion of cleavage, early embryo development (embryos with more than 4 cells), or both after IVP (18 h IVM–5% CO2 in air, and 18 h IVF, 48 h IVC–5% CO2, 10% O2, 85% N) in the presence of G (n = 1237) during each of the IVP phases or any possible combination of IVP phases was compared with the respective control (C, n = 804). Statistical analysis was performed by a chi-squared test; P &lt; 0.05 was considered significant. G improved cleavage and embryo development rates when present during IVM (79.4 and 57.8% vs. 64.5 and 38.2% for C) or both IVM and IVC (78.0 and 60.7% vs. 57.8 and 36.5%, respectively). When present only during 18 h of IVF, G had no effect on embryo production. However, an increased embryo development rate resulted from the combined exposure to G during IVF and IVM (56.4 vs. 29.6%), during IVF and IVC (55.3 vs. 35.5%), or at all IVP phases (56.6 vs. 34.9%). The latter effect resembled the one obtained after G addition only to the IVC medium (62.5 vs. 39.7%, respectively). We concluded that the addition of G to IVP substrates, at concentrations that mimic the in vivo TPaLP conditions, could promote bovine IVP efficiency.

[Detection of neutralizing antibodies in calves after single vaccination against foot-and-mouth disease virus type ASIA 1 in the field]

On June 20th 1984 appeared the first FMD-Type ASIA 1 outbreak in Greece. Around the outbreak all susceptible animals were vaccinated with ASIA 1 vaccine produced by IFFA Mereiux. Three weeks after this first vaccination blood samples have been collected and examined for neutralizing antibodies. From 101 examined calves 37 were younger than 6 months, 63 between 6-11 months and one was 12 months old. The titer of the first group was less than 1.2 in 14 and greater than 1.8 in 8 calves. By the second group (63 animals) the titer was less than 1.2 in 28 and greater than 1.8 in 11 calves. The 12 months old calf had a titer of 2.1. Generally the titer only of 59 out of the 101 examined calves was greater than or equal to 1.2 (59%). That means that the vaccine used had a weak immunogenicity.

[Laboratory diagnosis of foot-and-mouth disease and swine vesicular disease in the years 1962-1988 in Greece]

During 26 years (1962-1988) 499 samples from FMD-suspicious cases were examined in Greece. These materials came from 348 (70%) cattle, 95 (19%) pigs and 56 (11%) sheep and goats. The cattle with 197 (72.4%) positive cases seems to play the most important roll in FMD. The different isolated virus types belonged in 60 cases to type A, in 187 to type O, in 14 to type C, in 6 to type SAT 1 and in 2 cases to type ASIA 1, respectively. SVD was isolated in 3 cases from the same area and at the same time. Most samples have been examined by means of CF, cell culture, unweaned mice or by a combined way of these assays. From 363 samples have examined: A) 148 by CF, B) 32 by CF and cell culture, C) 64 by CF and baby mice D) 80 by CF, cell culture baby mice E) 8 by cell culture, F) 18 in cell culture and baby mice and G) 13 by baby mice. Form these samples were found positive in the case A) 74 (50%), E) 3 (38%) and none in case G. On the other hand, the correlation of the positive samples in combined assays were in case B) 9:21, C) 9:1, D) 8:22:16 and the case F) 3:2 respectively. The D case shows that CF detected less positive cases than the cell culture did. For a reliable labor diagnosis of FMD every sample must be examined by more than one method.