Background Hundreds of thousands of human embryos are cultured yearly at in vitro fertilization (IVF) centers worldwide, yet the vast majority fail to develop in culture or following transfer to the uterus. However, human embryo phenotypes have not been formally defined, and current criteria for embryo transfer largely focus on characteristics of individual embryos. We hypothesized that embryo cohort-specific variables describing sibling embryos as a group may predict developmental competence as measured by IVF cycle outcomes and serve to define human embryo phenotypes. Methodology/Principal Findings We retrieved data for all 1117 IVF cycles performed in 2005 at Stanford University Medical Center, and further analyzed clinical data from the 665 fresh IVF, non-donor cycles and their associated 4144 embryos. Thirty variables representing patient characteristics, clinical diagnoses, treatment protocol, and embryo parameters were analyzed in an unbiased manner by regression tree models, based on dichotomous pregnancy outcomes defined by positive serum ？-human chorionic gonadotropin (？-hCG). IVF cycle outcomes were most accurately predicted at ~70% by four non-redundant, embryo cohort-specific variables that, remarkably, were more informative than any measures of individual, transferred embryos: Total number of embryos, number of 8-cell embryos, rate (percentage) of cleavage arrest in the cohort and day 3 follicle stimulating hormone (FSH) level. While three of these variables captured the effects of other significant variables, only the rate of cleavage arrest was independent of any known variables. Conclusions/Significance Our findings support defining human embryo phenotypes by non-redundant, prognostic variables that are specific to sibling embryos in a cohort.
References
[1]
Behr B (1999) Blastocyst culture and transfer. Hum Reprod 14: 5–6.
[2]
Cowan CA, Klimanskaya I, McMahon J, Atienza J, Witmyer J, et al. (2004) Derivation of embryonic stem-cell lines from human blastocysts. N Engl J Med 350: 1353–1356.
[3]
Gardner DK, Lane M, Schoolcraft WB (2000) Culture and transfer of viable blastocysts: a feasible proposition for human IVF. Hum Reprod 15: Suppl 69–23.
[4]
Milki AA, Hinckley MD, Fisch JD, Dasig D, Behr B (2000) Comparison of blastocyst transfer with day 3 embryo transfer in similar patient populations. Fertil Steril 73: 126–129.
[5]
Chen H, Qian K, Hu J, Liu D, Lu W, et al. (2005) The derivation of two additional human embryonic stem cell lines from day 3 embryos with low morphological scores. Hum Reprod 20: 2201–2206.
[6]
Strelchenko N, Verlinsky O, Kukharenko V, Verlinsky Y (2004) Morula-derived human embryonic stem cells. Reprod Biomed Online 9: 623–629.
[7]
Mitalipova M, Calhoun J, Shin S, Wininger D, Schulz T, et al. (2003) Human embryonic stem cell lines derived from discarded embryos. Stem Cells 21: 521–526.
[8]
Artley JK, Braude PR, Johnson MH (1992) Gene activity and cleavage arrest in human pre-embryos. Hum Reprod 7: 1014–1021.
[9]
Barratt CL, St John JC, Afnan M (2004) Clinical challenges in providing embryos for stem-cell initiatives. Lancet 364: 115–118.
[10]
Hardy K, Spanos S, Becker D, Iannelli P, Winston RM, et al. (2001) From cell death to embryo arrest: mathematical models of human preimplantation embryo development. Proc Natl Acad Sci U S A 98: 1655–1660.
[11]
Dobson AT, Raja R, Abeyta MJ, Taylor T, Shen S, et al. (2004) The unique transcriptome through day 3 of human preimplantation development. Hum Mol Genet 13: 1461–1470.
[12]
Alikani M, Cohen J, Tomkin G, Garrisi GJ, Mack C, et al. (1999) Human embryo fragmentation in vitro and its implications for pregnancy and implantation. Fertil Steril 71: 836–842.
[13]
Ebner T, Moser M, Sommergruber M, Tews G (2003) Selection based on morphological assessment of oocytes and embryos at different stages of preimplantation development: a review. Hum Reprod Update 9: 251–262.
[14]
Ebner T, Yaman C, Moser M, Sommergruber M, Polz W, et al. (2001) Embryo fragmentation in vitro and its impact on treatment and pregnancy outcome. Fertil Steril 76: 281–285.
[15]
Giorgetti C, Terriou P, Auquier P, Hans E, Spach JL, et al. (1995) Embryo score to predict implantation after in-vitro fertilization: based on 957 single embryo transfers. Hum Reprod 10: 2427–2431.
[16]
Jun SH, O'Leary T, Jackson KV, Racowsky C (2006) Benefit of intracytoplasmic sperm injection in patients with a high incidence of triploidy in a prior in vitro fertilization cycle. Fertil Steril 86: 825–829.
[17]
Keltz MD, Skorupski JC, Bradley K, Stein D (2006) Predictors of embryo fragmentation and outcome after fragment removal in in vitro fertilization. Fertil Steril 86: 321–324.
[18]
Lan KC, Huang FJ, Lin YC, Kung FT, Hsieh CH, et al. (2003) The predictive value of using a combined Z-score and day 3 embryo morphology score in the assessment of embryo survival on day 5. Hum Reprod 18: 1299–1306.
[19]
Nagy ZP, Dozortsev D, Diamond M, Rienzi L, Ubaldi F, et al. (2003) Pronuclear morphology evaluation with subsequent evaluation of embryo morphology significantly increases implantation rates. Fertil Steril 80: 67–74.
[20]
Stone BA, Greene J, Vargyas JM, Ringler GE, Marrs RP (2005) Embryo fragmentation as a determinant of blastocyst development in vitro and pregnancy outcomes following embryo transfer. Am J Obstet Gynecol 192: 2014–2019; discussion 2019–2020.
[21]
Volpes A, Sammartano F, Coffaro F, Mistretta V, Scaglione P, et al. (2004) Number of good quality embryos on day 3 is predictive for both pregnancy and implantation rates in in vitro fertilization/intracytoplasmic sperm injection cycles. Fertil Steril 82: 1330–1336.
[22]
(2006) Guidelines on number of embryos transferred. Fertil Steril 86: 5 SupplS51–52.
[23]
Racowsky C (2002) High rates of embryonic loss, yet high incidence of multiple births in human ART: is this paradoxical? Theriogenology 57: 87–96.
[24]
Milki AA, Hinckley MD, Gebhardt J, Dasig D, Westphal LM, et al. (2002) Accuracy of day 3 criteria for selecting the best embryos. Fertil Steril 77: 1191–1195.
[25]
Neuber E, Mahutte NG, Arici A, Sakkas D (2006) Sequential embryo assessment outperforms investigator-driven morphological assessment at selecting a good quality blastocyst. Fertil Steril 85: 794–796.
[26]
Rijnders PM, Jansen CA (1998) The predictive value of day 3 embryo morphology regarding blastocyst formation, pregnancy and implantation rate after day 5 transfer following in-vitro fertilization or intracytoplasmic sperm injection. Hum Reprod 13: 2869–2873.
[27]
Mastenbroek S, Twisk M, van Echten-Arends J, Sikkema-Raddatz B, Korevaar JC, et al. (2007) In vitro fertilization with preimplantation genetic screening. N Engl J Med 357: 9–17.
[28]
Guzick DS, Overstreet JW, Factor-Litvak P, Brazil CK, Nakajima ST, et al. (2001) Sperm morphology, motility, and concentration in fertile and infertile men. N Engl J Med 345: 1388–1393.
[29]
Friedman J (1999) Greedy function approximation: A stochastic boosting machine. Department of Statistics, Stanford University. Technical Report.
[30]
Friedman J (1999) Stochastic gradient boosting. Department of Statistics, Stanford University. Technical Report.
[31]
Friedman J (2002) Tutorial: Getting started with MART in R. Department of Statistics, Stanford University.
[32]
Friedman J, Meulmann JJ (2003) Multiple additive regression trees with application in epidemiology. Statistics in medicine 22: 1365–1381.
[33]
Gardner DK, Schoolcraft WB, Wagley L, Schlenker T, Stevens J, et al. (1998) A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization. Hum Reprod 13: 3434–3440.
[34]
Racowsky C, Jackson KV, Cekleniak NA, Fox JH, Hornstein MD, et al. (2000) The number of eight-cell embryos is a key determinant for selecting day 3 or day 5 transfer. Fertil Steril 73: 558–564.
[35]
Braude P, Bolton V, Moore S (1988) Human gene expression first occurs between the four- and eight-cell stages of preimplantation development. Nature 332: 459–461.
[36]
Fisch JD, Milki AA, Behr B (1999) Sibling embryo blastocyst development correlates with the in vitro fertilization day 3 embryo transfer pregnancy rate in patients under age 40. Fertil Steril 71: 750–752.
[37]
Gardner DK, Surrey E, Minjarez D, Leitz A, Stevens J, et al. (2004) Single blastocyst transfer: a prospective randomized trial. Fertil Steril 81: 551–555.
[38]
Lane M, Gardner DK (1992) Effect of incubation volume and embryo density on the development and viability of mouse embryos in vitro. Hum Reprod 7: 558–562.
[39]
Rijinders PM, Jansen CAM (1998) The predictive value of day 3 embryo morphology regarding blastocyst formation, pregnancy, and implantation rate after day 5 transfer following in vitro fertilization or intracytoplasmic sperm injection. Hum Reprod 13: 2869–2873.
[40]
Spyropoulou I, Karamalegos C, Bolton VN (1999) A prospective randomized study comparing the outcome of in-vitro fertilization and embryo transfer following culture of human embryos individually or in groups before embryo transfer on day 2. Hum Reprod 14: 76–79.
[41]
Paria BC, Dey SK (1990) Preimplantation embryo development in vitro: cooperative interactions among embryos and role of growth factors. Proc Natl Acad Sci U S A 87: 4756–4760.
[42]
Broekmans FJ, Kwee J, Hendriks DJ, Mol BW, Lambalk CB (2006) A systematic review of tests predicting ovarian reserve and IVF outcome. Hum Reprod Update 12: 685–718.
[43]
Jain T, Soules MR, Collins JA (2004) Comparison of basal follicle-stimulating hormone versus the clomiphene citrate challenge test for ovarian reserve screening. Fertil Steril 82: 180–185.
[44]
Srouji SS, Mark A, Levine Z, Betensky RA, Hornstein MD, et al. (2005) Predicting in vitro fertilization live birth using stimulation day 6 estradiol, age, and follicle-stimulating hormone. Fertil Steril 84: 795–797.
[45]
Watt AH, Legedza AT, Ginsburg ES, Barbieri RL, Clarke RN, et al. (2000) The prognostic value of age and follicle-stimulating hormone levels in women over forty years of age undergoing in vitro fertilization. J Assist Reprod Genet 17: 264–268.
[46]
Scott RT Jr, Elkind-Hirsch KE, Styne-Gross A, Miller KA, Frattarelli JL (2007) The predictive value for in vitro fertility delivery rates is greatly impacted by the method used to select the threshold between normal and elevated basal follicle-stimulating hormone. Fertil Steril.
