1. Reproductive BioMedicine Online
Larger oocyte cohorts maximize fresh IVF cycle birth rates and availability of surplus high-quality blastocysts for cryopreservation 
Matthew T. Connell, Kevin S. Richter, Kate Devine, Micah J. Hill, Alan H. DeCherney, Joseph O. Doyle, Michael J. Tucker, Michael J. Levy 
Reproductive BioMedicine Online 
DOI: /j.rbmo
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2. Figure 1
Flow diagram illustrating the context of the selected study population in relation to all oocyte retrievals for fresh autologous IVF and embryo transfer performed at our centre. 2PN = two-pronuclear; DOR = diminished ovarian reserve; PGT = preimplantation genetic testing.
Reproductive BioMedicine Online DOI: ( /j.rbmo )
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3. Figure 2
Frequency distribution of numbers of oocytes retrieved per cycle. Our target cohort size of approximately 12–16 retrieved oocytes per cycle is indicated by the contrasting green bars.
Reproductive BioMedicine Online DOI: ( /j.rbmo )
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4. Figure 3
Fertilization rates according to the number of oocytes retrieved. Each data point illustrates the observed average fertilization rate for all cycles of that cohort size, with 95% confidence intervals indicated by the error bars. The red trend line, derived from linear regression modelling of the raw data, illustrates the significant decline in fertilization with increasing oocyte numbers (R2 = 0.0027, P < 0.0001).
Reproductive BioMedicine Online DOI: ( /j.rbmo )
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5. Figure 4
Treatment outcomes according to the number of oocytes in a retrieved cohort. In A–C, cohort size is categorized as: 1 (n = 30); 2 (n = 76); 3 (n = 136); 4 (n = 168); 5–6 (n = 588); 7–10 (n = 1929); 11–15 (n = 2776); 16–20 (n = 2203); 21–25 (n = 1143); or >25 (n = 1144). Error bars indicate 95% confidence intervals. (A) The percentage of cycles with no viable embryos available for transfer. (B) Live birth rates per fresh embryo transfer, with numbers of transfers indicated on corresponding columns. (C) Live-born children per freshly transferred embryo. In D–F, outcomes are plotted in increments of 1 oocyte, with the empirically best fitting model trend lines superimposed in red. (D) The percentage of fresh embryo transfer cycles having additional surplus good-quality blastocyst(s) available for cryopreservation after fresh transfer. (E) The average number of surplus good-quality blastocysts cryopreserved per cycle after fresh transfer. (F) The estimated total number of children that would be born per retrieval assuming the eventual transfer of all cryopreserved embryos.
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6. Figure 5
Incidence of severe ovarian hyperstimulation syndrome (OHSS). (A) Frequency of severe OHSS per retrieval according to treatment year, with trend lines for gonadotrophin-releasing hormone (GnRH) antagonist suppression and GnRH agonist trigger protocols superimposed. (B) Frequency of severe OHSS according to cohort size and trigger medication (human chorionic gonadotrophin [HCG] versus GnRH agonist). Group sample sizes: for HCG triggers, n = 505, 1494, 1854, 1253, 544 and 362, respectively per cohort size group; for GnRH agonist triggers, n = 83, 435, 922, 950, 599 and 782, respectively per cohort size group.
Reproductive BioMedicine Online DOI: ( /j.rbmo )
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