Larger donor oocyte cohorts maximize potential number of live born infants per retrieval among recipient in vitro fertilization (IVF) patients

BACKGROUND: Controversy exists regarding whether retrieval of large oocyte cohorts adversely affects IVF birth outcomes. OBJECTIVE: Primarily, to evaluate live birth outcomes among donor oocyte recipients undergoing fresh embryo transfers, according to retrieved oocyte cohort size. Secondarily, to quantify the potential contribution of surplus cryopreserved embryos to the number of achievable births per retrieval. MATERIALS AND METHODS: A retrospective cohort study of live birth outcomes of oocyte donation cycles (donor maximum age 33 years) during 2009-2014 was performed. Each donated cohort was shared among 1-3 recipients. Donor retrievals were excluded from analysis if any recipient was known (non-anonymous donation), had oocytes or embryos cryopreserved without undergoing fresh embryo transfer, was diagnosed with uterine factor infertility, or used non-ejaculated sperm. Vitrification of surplus good quality expanded blastocysts (minimum ICM and trophectoderm grades of BB) was performed on day 5 or 6 after retrieval. To estimate potential births from vitrified blastocysts, we assumed a 29% birth rate, our historically observed success rate per vitrified/warmed blastocyst among donor oocyte recipients. RESULT(S): A total of 1,771 eligible oocyte donation cycles were evaluated. Oocyte cohorts with a total of 2-5 or 6-9 MII oocytes retrieved from donors were less likely to result in live birth from fresh embryo transfer(s) to one or more recipients (43% and 56% versus R73%, p<0.0001 versus larger cohorts). The average number of live born infants from fresh embryo transfers per donor retrieval was significantly lower with retrievals of only 2-5 or 6-9 total MII oocytes compared to larger oocyte cohorts. The number of infants born from fresh transfers plateaued at an average of 1.3 per retrieval when cohort size was 15-19 MII oocytes or larger. Live born infants per freshly transferred embryo was higher for embryos originating from larger oocyte cohorts. Each incremental increase in retrieved cohort size resulted in a significant increase in the number of surplus good quality blastocysts cryopreserved after fresh transfer, and in the estimated total number of potential infants per retrieval. CONCLUSION(S): Previous data have suggested that IVF live birth rates may be maximized with intermediate oocyte cohort size, while retrieval of larger cohorts is associated with poorer outcomes (ref). This current analysis of IVF outcomes among recipients of oocytes donated by healthy, young and presumably fertile oocyte donors refutes this notion. It demonstrates that live birth from fresh embryo transfer is not adversely affected by retrieval of more oocytes. Numbers of fresh-transfer live born infants per donor retrieval, and proportions of live born infants per freshly transferred embryo, were both maximized with retrieval of larger oocyte cohorts. Secondarily, in addition to the beneficial impacts on fresh embryo transfers, we also noted a steady and substantial increase with increasing retrieved cohort size in the numbers of good quality surplus blastocysts available for cryopreservation after fresh transfer. Therefore, the potential cumulative number of infants per retrieval event increases significantly as retrieved oocyte cohort size increases. FINANCIAL SUPPORT: This research was supported, in part, by Intramural research program of the Program in Reproductive and Adult Endocrinology, NICHD, NIH. References: 1. Sunkara et al., Hum Reprod 2011;26:1768-74.

Chart 1. Positive pregnancy test clinical pregnancy and implantation rates of D5 embryos

OBJECTIVE: The aim of this study was to evaluate if clinical outcomes differ between day 5 blastocyst stage vitrified embryos thawed on the day prior to versus the day of transfer. MATERIALS AND METHODS: Design: Retrospective study. Setting: Academic fertility center. Interventions: Blastocysts vitrified and thawed the day prior to transfer (Group 1) were compared to those thawed the day of transfer (Group 2). All embryos were vitrified on the cryolock device and all patients underwent endometrial priming. Pregnancies were initially detected by serum b-human chorionic gonadotropin (hCG) concentrations. Clinical pregnancy and implantation were confirmed by transvaginal ultrasound (US). Exclusion criteria included: donor oocyte, pre-implantation genetic testing, and gestational carrier cycles, as well as cycles that included embryos imported from different centers and cycles with combined day 5 (D5) and day 6 (D6) frozen embryo transfers. Outcome Measures: Positive pregnancy test (serum b-hCG concentration >6 IU/L) per cryothaw cycle, clinical pregnancy (CPR) and implantation rates (number of sacs observed on US over the number of embryos transferred). Statistics: X2-square and t-test were used as appropriate. P<0.05 was considered statistically significant. RESULT(S): A total of 112 thawed blastocysts (88 D5, 24 D6) from 94 patients were included in the analysis. Patient characteristics did not differ between the 2 groups of embryos (Table 1). When all blastocyst stage embryos (D5 and D6) were compared between the Group 1 and Group 2, positive pregnancy test (61.7% vs 70.2, p¼0.51, respectively), CPR (61.7% vs 62.2%, p¼1.00, respectively) and, implantation (85.0% vs 82.4%, p¼0.76, respectively) rates did not differ. When the analysis was restricted to D5 embryos, which were the blastocysts affected by the intervention implemented, positive pregnancy test, CPR and implantation rates were similar amongst the groups (Chart 1). CONCLUSION(S): According to our findings, thawing D5 blastocysts the day prior to transfer does not impact CPR or implantation rates, thus allowing embryologists some flexibility to the timing of D5 embryo thaw. FINANCIAL SUPPORT: none.

P-65 P-64

EFFICACY OF GENETIC COUNSELING IN THE PREIMPLANTATION GENETIC DIAGNOSIS (PGD) SETTING: PATIENT OPINIONS AND PERSPECTIVES. D. Goldberg-Strassler, E. Armenti, R. Cabey, J. Gay, A. Jordan. Reprogenetics, Livingston, NJ.

LARGER DONOR OOCYTE COHORTS MAXIMIZE POTENTIAL NUMBER OF LIVE BORN INFANTS PER RETRIEVAL AMONG RECIPIENT IN VITRO FERTILIZATION (IVF) PATIENTS. Nicole Doyle,a Kevin Richter,b Micah Hill,c George Patounakis,d Michael Tucker,a Joseph Doyle,a Michael Levy.a aNICHD; bShady Grove Fertility; cWRNMMC; d Reproductive Medicine Associates of Florida.

MII oocytes in retrieved cohort Donor retrievals Live birth per retrieval - fresh transfer(s) Live born infants per retrieval - fresh transfer(s) Live born infant per freshly transferred embryo Surplus cryopreserved embryos per retrieval Total estimated infants per retrieval

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PCRS Abstracts

2-5 83 36 (43%) 0.5 30%

6-9 252 140 (56%) 0.7 35%

BACKGROUND: As genetic services become more commonplace it is important to understand the usefulness and impact of genetic counseling.

10-14 450 327 (73%) 1.1 40%

15-19 422 312 (74%) 1.3 41%

20-24 281 217 (77%) 1.3 42%

25-29 178 140 (79%) 1.3 43%

30-39 91 67 (74%) 1.5 45%

40+ 14 11 (79%) 1.3 51%

0.5

1.2

2.1

3.1

4.7

5.7

6.7

10.6

0.6

1.0

1.7

2.2

2.7

3.0

3.4

4.4

Vol. 107, No. 3, Supplement, March 2017