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Blastocyst culture and transfer in clinically assisted reproduction: a committee opinion (2018)


INTRODUCTION

Extending the duration of embryo culture to the blastocyst stage for assisted reproduction offers several theoretical advantages over the transfer of cleavage-stage embryos. These include 1) a higher implantation rate and livebirth rates, 2) the opportunity to potentially select the most viable embryo(s) for transfer, 3) the potential decrease in the number of embryos transferred, and 4) better temporal synchronization between embryo and endometrium at the time of embryo transfer since implantation in vivo generally occurs on day 5–7 (1–9).

Advances in our understanding of the dynamic physiology of early human embryos have led to the development of culture systems now capable of yielding viable blastocysts with greater consistency. Whereas most culture systems involve two distinct media used sequentially (1, 10, 11), others use a single medium (12, 13). Studies have shown that a single-step medium supports blastocyst development equivalently to that of sequential media (14–16).

Commercially available media provide the means for any in vitro fertilization (IVF) program to incorporate extended culture systems and blastocyst transfer into its treatment protocols. The prevailing challenge is to determine prospectively, for each patient, whether this technology will increase the likelihood of a healthy baby compared with cleavage-stage transfer. This challenge is complicated by our continuing inability to predict with certainty which cleavage-stage embryos will develop into viable blastocysts.

Assessing Live-birth Rates Based on Day of Transfer

Proponents of extended culture believe that blastocyst embryos have higher reproductive potential due to lower rates of aneuploidy and better synchrony with the uterine milieu. For these reasons, blastocyst transfer should translate into higher implantation and, more importantly, live-birth rates.

The results of a randomized trial in a good-prognosis population (>10 follicles >12 mm on day of human chorionic gonadotropin [hCG]) revealed a higher implantation rate (fetal heart beat per embryo transferred) after blastocyst transfer than after cleavagestage embryo transfer (50.5% vs. 30.1%, P<.01) (17). More recent trials in good-prognosis patients (defined by such factors as age, number of previous failed attempts, ovarian response, and number and quality of embryos) have provided consistent evidence for an increased likelihood of live birth after transfer of fresh blastocysts compared with cleavage-stage embryos (18–20).

Looking at women with at least 2 prior failed implantations, a randomized controlled trial (RCT) of 118 women under age 40 compared outcomes for fresh cleavage vs. blastocyst embryo transfers (21). The researchers reported no statistical difference in implantation rates (22/152 [14.5%] vs. 21/173 [12.1%], respectively, P¼.535) or pregnancy rates (19/57 [33.3%] vs. 17/61 [27.9%], respectively, P¼.519). This study, like another small study, which found trends toward higher rates of implantation, clinical pregnancy, and live-birth rates following blastocyst transfer, but the differences were not clinically significant (22). These two small studies echo previous findings of higher implantation rates with blastocyst transfer (17, 23).

An updated 2016 meta-analysis added four new RCTs to compare clinical pregnancy rate (fetal cardiac activity), livebirth rate per embryo transfer (live birth rate, >20 weeks), and cumulative pregnancy rate (fresh and frozen thawed transfers) per oocyte retrieval and in blastocyst vs. cleavage-stage embryo transfers (24). The analysis included 27 RCTs of women undergoing assisted reproductive technology (ART) using autologous oocytes (15 with good-prognosis patients, 3 with poor-prognosis patients, 9 with unselected patients). Pooling of implantation rate data could not be included due to issues with validity.

According to the authors of the meta-analysis, there was moderate evidence for higher clinical pregnancy rate after blastocyst transfers (odds ratio [OR] 1.30, confidence interval [CI] 1.14–1.47); restricting to studies with a low risk of bias did not impact this observation. There was low-quality evidence for higher live-birth rate after blastocyst transfers (OR 1.48, CI 1.20–1.82; 13 RCTs, 1,630 women, I2 ¼ 45%). This effect on live-birth rate was lost when restricted to studies with a low risk of bias but was speculated to have been an underpowered subgroup analysis (n¼ 539 women). There was no difference between blastocyst- and cleavage-stage transfer based on number of embryos transferred, prognosis, or day of randomization.

There was no difference observed in cumulative pregnancy rate between the groups (OR 0.89, CI 0.64–1.22; five RCTs, 632 women, I2 ¼ 75%, very low quality of evidence). There was no difference between blastocyst- and cleavagestage transfer based on number of embryos transferred, prognosis, or day of randomization. A post hoc subgroup analysis found differences according to method of cryopreservation: cleavage-stage transfer showed benefit in the four studies using slow freezing, but there was a higher cumulative pregnancy rate for blastocyst transfer in the single study with vitrification (OR 2.44, CI 1.17–5.12). A significant limitation to this review is that most included studies only cryopreserved blastocysts on day 5 of culture, rather than including day 6 (or 7) blastocysts; current practice generally allows for freezing day 5 or 6 cryopreservation, which may allow for more embryos to be cryopreserved and therefore higher cumulative pregnancy rates in cases of blastocyst culture.

There were no differences between the groups for the rates of multiple pregnancy, high-order multiple pregnancy, or miscarriage. Rates of embryo cryopreservation were lower (OR 0.48, CI 0.40–0.57; 14 studies, 2,292 women, I2¼ 84%, low quality of evidence) and failure to transfer embryos was higher in the blastocyst group (OR 2.50, CI 1.76–3.55; 17 studies, 2577 women, I2¼36%, moderate quality of evidence). Since laboratories vary in blastulation rates and embryo potential may be adversely affected by blastulation rate, it is difficult to argue uniformly that suboptimal embryos do not blastulate.

This meta-analysis noted an overall low quality of evidence. Reasons cited were risk of bias, the fact that only 13 of 27 studies reported live-birth rate, and the fact that only 5 of 27 studies reported cumulative pregnancy rate with high heterogeneity due to different methods of cryopreservation. Because this meta-analysis excluded cycles that employed preimplantation genetic testing (PGT) and very few reported a cumulative pregnancy rate, this may not accurately represent current practice culture. Other factors that can make it challenging to interpret trials designed to assess efficacy of blastocyst transfer are variations in patient populations, culture systems, individual laboratory experience, and embryo-transfer policies among programs.

While there is evidence suggesting that blastocyst transfer may yield better rates of clinical pregnancy and live birth, more studies are needed to incorporate outcomes for single-embryo transfer, cumulative pregnancy rate, and PGT.

Cancelled Transfer

Although there is intense investigation to find markers to identify developmentally competent embryos (25–27), none are recommended for routine use. This lack of established markers for predicting blastocyst development increases the risk of having no embryos to transfer despite observations of adequate development in vitro on day 2–3. There is some evidence to suggest that the numbers of blastomeres (28–30) and the degree of fragmentation observed on day 3 (31) are associated with the potential for blastocyst formation. However, these associations do not necessarily correlate with blastocyst viability, and the ability to produce blastocysts varies widely among patients, ranging from 0% to almost 100% (17). Consequently, the incidence of cancelled transfers is significantly higher in unselected patients randomized to extended culture (16 RCTs: 8.9% vs. 2.8%, blastocyst vs. cleavage stage, respectively; OR 2.85; 95% CI 1.97–4.11) but is not different in good-prognosis patients (OR 1.50; 95% CI 0.79–2.84; 9 RCTs [32]). More recent efforts have therefore focused on identifying clinical factors associated with blastocyst development and pregnancy (33) and on developing a model to predict blastocyst-transfer cancellation rates (34). While several clinical and cyclebased factors have been associated with blastocyst development (such as patient age, parity, antral follicle count, fertilization technique, and number and quality of embryos), prospective testing of derived models in multicenter trials has yet to be undertaken. Time lapse microscopy has demonstrated a capacity to predict which cleavage stage embryos will successfully blastulate (35–37), though the expense of this technology may limit its widespread use. Other areas of noninvasive embryo selection such as metabolomics and proteomic profiles are active areas of study to optimize embryo selection, and potentially also blastocyst formation. These tools may allow for further ability to advise patients going through IVF, particularly as practices establish guidelines regarding when to transfer cleavage embryos vs. continue culture to a blastocyst embryo.

Elective Single-embryo Transfer

Studies have observed high implantation rates for transferred blastocysts (17). A retrospective cohort study utilizing the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) database demonstrated a 10%–15% reduction in live-birth rate and 47% decrement in twinning when comparing elective single-embryo transfer (eSET) to double-blastocyst transfer (38). Furthermore, two other retrospective analyses of nonrandomized goodprognosis patients with elective single-blastocyst or doubleblastocyst transfer using autologous embryos have shown that eSET significantly reduced the incidence of twin pregnancies (1% vs. 44% [39]; 2% vs. 25% [40]), while pregnancy rates were not compromised (65% vs. 63% [41]; 63% vs. 61% [40]). In donor-egg recipients, live-birth rates were lower with eSET vs. double-embryo transfer (DET) (64% vs. 74%, P¼.012), while twin rates were significantly reduced (2% vs. 54%) (39).

Therefore, transfer of a single blastocyst in good-prognosis patients dramatically decreases the incidence of multiple pregnancy while maintaining pregnancy rates similar to those following double blastocyst transfer.


Monozygotic Twinning

Studies examining the risk associated with monozygotic twinning (MZT) from blastocyst transfer have yielded inconsistent results. While most of the studies (41–47), including two meta-analyses (48, 49) and a large study exploring almost 9,000 IVF gestations (50), have reported a significantly increased risk following blastocyst transfer compared with cleavage-stage transfer, other reports have documented no difference in this incidence (51, 52). One study demonstrated the incidence of monozygotic twins between cleavage and extended culture to be 2.09% vs. 2.8% (P¼.008), demonstrating a small absolute risk increase (50).

Monozygotic twinning following blastocyst transfer also is associated with female age <35 years (42, 45) and has been decreasing in incidence in the past 10–15 years (49, 51, 53). The rationale for the occurrence of MZT is unknown but felt to possibly be related to experience with blastocyst culture and transfer. Differing culture systems among programs have led to variations in culture-induced alterations in the zona pellucida and/or the embryo-hatching process (43–45, 53). While one study investigating risk factors that predispose IVF embryos to monochorionic twinning revealed blastocyst transfer as an independent predictor (OR 2.48; 95% CI 1.62–3.80 [54]), another showed no increase in MZT when comparing blastocyst- to cleavage-stage transfers when controlling for patient prognosis and embryo quality factors (55).

Until further studies are undertaken to clarify the association between extended culture and zygosity/chorionicity, patients should be counseled that there may be a small statistically significant increased risk of MZT and monochorionic twinning with blastocyst- vs. cleavage-stage embryo transfer, though the increase in absolute risk remains small.

Altered Sex Ratio

Blastocyst transfer may be associated with an increased likelihood of conceiving a male offspring, and this may be affected by mode of fertilization. The majority of earlier studies investigating sex-ratio imbalance, including a study evaluating greater than 100,000 births from IVF/intracytoplasmic sperm injection (ICSI) in China, reported a higher frequency of males compared with either natural pregnancy (56) or after day-3 transfer (41, 57–59). This observation likely relates to the underlying observation that, in animal models, male embryos develop faster (60), and embryologists tend to select preferentially more developmentally advanced blastocysts for transfer. While several of these studies had small sample sizes and failed to show statistical significance, a meta-analysis of four trials demonstrated a higher male-to-female ratio following blastocyst transfer compared with cleavage-stage transfer (56.8% vs. 50.9%; OR 1.29; 95% CI 1.10–1.51 in 1,485 vs. 1,102 births, respectively [49]). This observation has been confirmed further for 5,773 IVF children in a SART CORS national database study (49.5% males for day 3 vs. 54.9% males for all transfers beyond day 3; P<.0001), although children born after ICSI from blastocyst transfers were less likely to be male than those from IVF (OR 0.81; 95% CI, 0.71–0.92; 5.3% decrease [61]). The reasons for this decreased likelihood in male offspring after ICSI are unknown.

Available data support blastocyst transfer being associated with a small increased likelihood of conceiving a male child with standard insemination but a decreased likelihood of a male child following use of ICSI.


Cryopreservation

Logically, patients randomized to blastocyst transfer have fewer embryos available for cryopreservation than those randomized to cleavage-stage embryo transfer and cryopreservation (19, 32). This finding is supported by a meta-analysis of eight RCTs comparing cryopreservation rates from cleavagestage vs. blastocyst-stage groups in which patients had an equal number of embryos transferred (OR 0.28; 95% CI 0.14–0.55 [32]).

Vitrification, a method of rapid cryopreservation, is an alternative to slow-freeze methods. It has the theoretical advantage of providing better protection from cryoinjury by reducing the formation of intracellular ice crystals (62). Vitrification has provided excellent survival and implantation rates of thawed blastocysts in most programs (63, 64) with equivalent success rates but improved neonatal outcomes compared with fresh embryo transfers (65). However, additional research aimed at improving and comparing different methods of blastocyst vitrification is still ongoing (66, 67). Although the success achieved with blastocyst cryopreservation among centers has varied, those that perform extended culture also should have an established cryopreservation program for surplus blastocysts. As the cumulative delivery rate (i.e., the delivery rate from fresh and frozen transfers) should be the measure for assessing optimal cycle outcome, the overall efficiency of blastocyst cryopreservation protocols is of critical importance when evaluating the optimum day of embryo transfer.

Neonatal Outcomes

Maternal-fetal morbidity increases with multiple gestation. Extended culture may significantly reduce multi-fetal gestation by improving embryo selection for eSET. One study showed that children born from blastocyst transfer (n¼1,311) were at a slightly increased risk for adverse neonatal outcomes, such as preterm birth (<37 weeks) (OR 1.35; 95% CI 1.07–1.71), compared with children conceived after cleavage transfer (n¼12,562), though the absolute risk is small (0.091% vs. 0.072%, respectively) (68). One metaanalysis of six observational studies found an increased risk of preterm birth (OR 1.32, CI 1.19–1.46) and congenital anomalies (OR 1.29, CI 1.03–1.62) following blastocyst (vs. cleavage-stage) transfer. The study found no significant differences in very preterm birth (<32 weeks), low birth weight (<2,500 g), or very low birth weight (<1,500 g) (69). The clinical significance and cause of these small increased risks are unclear; they may be due to patient selection for extended culture and/or culture conditions. The increased preterm birth may be explained, in part, by the association of male gender with preterm birth and the higher male-to-female ratio following blastocyst transfer (49, 69).

Some studies suggest that extended culture may impact offspring via differences in gene expression and epigenetic mutations (69–74), while other studies appear reassuring (75), particularly regarding the blastocyst stage (76). The mechanisms via which culture media may influence epigenetic modifications are unknown. Certain components of the culture medium, such as the methionine concentration, have been implicated (77). Concerns about the potential risks of culture, particularly using media with undefined components and/or concentrations, merit careful consideration. Every effort should be made to standardize culture conditions and to continue the ongoing evaluation of the health of offspring following extended culture and blastocyst transfer. On balance, the impact of blastocyst culture on improving neonatal outcomes is mostly from increased utilization of eSET and the subsequent decrease in multifetal gestation.

Practical Laboratory-related Issues

There are several laboratory-related issues that warrant consideration when weighing whether to offer blastocyst transfer to patients. The decision to offer blastocyst transfer may depend on the success of extended culture for an individual laboratory. Extended culture requires greater incubator capacity to hold the embryos for the additional 2 to 3 days in culture. Moreover, managing the potential increased workload of relocating embryos to fresh medium on day 3 if sequential media are used and, possibly, the need to perform two embryo-cryopreservation runs (cleavage as well as blastocyst), likely requires additional embryologists (78). Finally, embryos developing to the blastocyst stage appear to benefit from culture in a low-oxygen environment (79, 80). Two prospective randomized trials (81, 82) have each shown improved blastocyst formation rates (45.7% vs. 35.2%, P<.03 [81]), numbers of cryopreserved embryos (71.0% vs. 54.9%, P<.011 [68]), and increased clinical pregnancy rates (45.7% vs. 35.2%, P<.03 [81]; 71.0% vs. 54.9%, P¼.011 [82]) after culture in oxygen tension that is physiologically appropriate for the fallopian tubes (5%) compared with atmospheric oxygen (19%–21%) tension.

SUMMARY

  • In good-prognosis patients, blastocyst transfer results inincreased live-birth rates compared with transfer of equalnumbers of cleavage-stage embryos. Given the high implantationrate with blastocysts, eSET should be routinelyutilized to minimize multiple gestation.
  • Reliable criteria to identify embryos destined to develop toviable blastocysts in vitro remain to be established.
  • Extended culture yields fewer surplus embryos for cryopreservationcompared with cleavage-stage cryopreservation.
  • Although the data are conflicting, blastocyst culture and transfer may be associated with a small increased risk of monozygotic twinning when compared with cleavagestage transfer.
  • Blastocyst culture may be associated with a small increased risk of adverse neonatal outcomes, though no causal relationship has been proven.
  • Embryologists must be sure to have appropriate equipment, protocols, and personnel to routinely offer blastocyst transfer.

CONCLUSIONS

  • Evidence supports blastocyst transfer in good-prognosis patients. Elective single-embryo transfer should be routinely utilized to minimize the high risk of multiples in good-prognosis patients.
  • Future studies are needed about selection of embryos destined to blastulate to avoid no-transfer scenarios.

Acknowledgments

This report was developed under the direction of the Practice Committee of the American Society for ReproductiveMedicine (ASRM) incollaborationwith the Society for Assisted Reproductive Technology (SART) as a service to its members and other practicing clinicians. Although this document reflects appropriate management of a problem encountered in the practice of reproductive medicine, it is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs of the individual patient, available resources, and institutional or clinical practice limitations. The Practice Committees and the Board of Directors of ASRM and SART have approved this report.

This document was reviewed by ASRM members and their input was considered in the preparation of the final document. The Practice Committee acknowledges the special contribution of Matthew ‘‘Tex’’ VerMilyea, Ph.D., Jennifer Hirschfeld- Cytron, M.D., and Kathryn Campbell Calhoun, M.D. The following members of the ASRM Practice Committee participated in the development of this document. All Committee members disclosed commercial and financial relationships with manufacturers or distributors of goods or services used to treat patients. Members of the Committee who were found to have conflicts of interest based on the relationships disclosed did not participate in the discussion or development of this document.

Alan Penzias, M.D.; Kristin Bendikson, M.D.; Samantha Butts, M.D., M.S.C.E.; Tommaso Falcone, M.D.; Susan Gitlin, Ph.D.; Clarisa Gracia, M.D., M.S.C.E.; Karl Hansen, M.D., Ph.D.; Sangita Jindal, Ph.D.; Jennifer Mersereau, M.D.; Randall Odem, M.D.; Robert Rebar, M.D.; Richard Reindollar, M.D.; Mitchell Rosen, M.D.; Jay Sandlow, M.D.; Peter Schlegel, M.D.; Dale Stovall, M.D.

REFERENCES

  1. Gardner DK, Lane M. Culture and selection of viable human blastocysts: a feasible proposition for human IVF? Hum Reprod Update 1997;3:367–82.
  2. Pool TB, Atiee SR, Martin JE. Oocyte and embryo culture: Basic concepts and recent advances. Infert Reprod Med Clin N Amer 1998;9:181–203.
  3. Tsirigotis M. Blastocyst stage transfer: pitfalls and benefits: Too soon to abandon current practice? Hum Reprod 1998;13:3285–9.
  4. Gardner DK, Schoolcraft WB. No longer neglected: the human blastocyst. Hum Reprod 1998;13:3289–92.
  5. Desai NN. The road to blastocyst transfer. Hum Reprod 1998;13:3292–4.
  6. Quinn P. Some arguments on the pro side. Hum Reprod 1998;13:3294–5.
  7. Bavister BD, Boatman DE. The neglected human blastocyst revisited. Hum Reprod 1997;12:1607–10.
  8. Behr B. Blastocyst culture without co-culture: role of embryo metabolism. J Assist Reprod Genet 1997;14:13S.
  9. Menezo YJ, Hamamah S, Hazout A, Dale B. Time to switch from coculture to sequential defined media for transfer at the blastocyst stage. Hum Reprod 1998;13:2043–4.
  10. Gardner DK, Vella P, Lane M, Wagley L, Schlenker T, Schoolcraft WB. Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. Fertil Steril 1998;69:84–8.
  11. Jones GM, Trounson AO, Gardner DK, Kausche A, Lolatgis N, Wood C. Evolution of a protocol for successful blastocyst development and pregnancy. Hum Reprod 1998;13:169–77.
  12. Macklon NS, Pieters MH, Hassan MA, Jeucken PH, EijkemansMJ, Fauser BC. A prospective randomized comparison of sequential versus monoculture systems for in-vitro human blastocyst development. Hum Reprod 2002;17:2700–5.
  13. Biggers JD, Racowsky C. The development of fertilized human ova to the blastocyst stage in KSOM(AA) medium: is a two-step protocol necessary? Reprod Biomed Online 2002;5:133–40.
  14. Hardarson T, Bungum M, Conaghan J, Meintjes M, Chantilis SJ, Molnar L, et al. Noninferiority, randomized, controlled trial comparing embryo development using media developed for sequential or undisturbed culture in a time-lapse setup. Fertil Steril 2015;104:1452–9.
  15. Sfontouris IA, et al. Blastocyst culture using single versus sequential media in clinical IVF: a systematic review and meta-analysis of randomized controlled trials. J Assist Reprod Genet 2016;33:1261–72.
  16. Dieamant F, et al. Single versus sequential culture medium: which is better at improving ongoing pregnancy rates? A systematic review and meta-analysis. JBRA Assist Reprod 2017;21:240.
  17. Gardner DK, Schoolcraft WB, Wagley L, Schlenker T, Stevens J, Hesla J. A prospective randomized trial of blastocyst culture and transfer in in vitro fertilization. Hum Reprod 1998;13:3434–40.
  18. Glujovs ky D, Blake D, Farquhar C, Bardach A. Cleavage stage versus blastocyst stage embryo transfer in assisted reproductive technology. Cochrane Database Syst Rev 2012:CD002118.
  19. Papanikolaou EG, D'haeseleer E, Verheyen G, Van de Velde H, Camus M, Steirteghem A, et al. Live birth rate is significantly higher after blastocyst transfer than after cleavage-stage embryo transfer when at least four embryos are available on day 3 of embryo culture. Hum Reprod 2005;20:3198–203.
  20. Papanikolaou EG, Camus M, Kolibinakis EM, Van Landuyt L, Van Steirteghem A, Devroey P. In vitro fertilization with single blastocyst stage versus single cleavage-stage embryos. N Engl J Med 2006;354:1139–46.
  21. Aziminekoo E, Mohseni Salehi MS, Kalantari V, Shahrokh Tehraninejad E, Hahollahi F, Rashidi B, et al. Pregnancy outcome after blastocyst stage transfer comparing to early cleavage stage embryo transfer. Gynecol Endocrinol 2015;31:880–4.
  22. Levitas E, Lunenfeld E, Har-Vardi I, Albotiano S, Sonin Y, Hackmon-Ram R, et al. Blastocyst-stage embryo transfer in patients who failed to conceive in three or more day 2-3 embryo transfer cycles: a prospective, randomized study. Fertil Steril 2004;81:567–71.
  23. Frattarelli JL, Leondires MP, McKeeby JL, Miller BT, Segars JH. Blastocyst transfer decreases the multiple pregnancy rates in in vitro fertilization cycles: a randomized controlled trial. Fertil Steril 2003;79:228–30.
  24. Glujovs ky D, Farquhar C, Quinteiro Retamar AM, Alvarez Sedo CR, Blake D. Cleavage stage versus blastocyst stage embryo transfer in assisted reproductive technology. Cochrane Database Syst Rev 2016;30:CD002118.
  25. Seli E, Robert C, Sirard MA. OMICS in assisted reproduction: possibilities and pitfalls. Mol Hum Reprod 2010;16:513–30.
  26. Schoolcraft WB, Fragouli E, Stevens J, Munne S, Katz-Jaffe MG, Wells D. Clinical application of comprehensive chromosomal screening at the blastocyst stage. Fertil Steril 2010;94:1700–6.
  27. Wong CC, Loewke KE, Bossert NL, Behr B, De Jonge CJ, Baer TM, et al. Noninvasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage. Nat Biotechnol 2010;28:1115–21.
  28. Racowsky C, Jackson KV, Cekleniak NA, Fox JH, Hornstein MD, Ginsburg ES. The number of 8-cell embryos is a key determinant for selecting day 3 or day 5 transfer. Fertil Steril 2000;73:558–64.
  29. Langley MT, Marek DM, Gardner DK, Doody KM, Doody KJ. Extended embryo culture in human assisted reproduction. Hum Reprod 2001;16:902–8.
  30. Neuber E, Rinaudo P, Trimarchi JR, Sakkas D. Sequential assessment of individually cultured human embryos as an indicator of subsequent good embryo quality blastocyst development. Hum Reprod 2003;18:1307–12.
  31. Shoukir Y, Chardonnens D, Campana A, Bischof P, Sakkas D. The rate of development and time of transfer play different roles in influencing the viability of human blastocyst. Hum Reprod 1998;13:676–81.
  32. Papanikolaou EG, Kolibianakis EM, Tournaye H, Venetis CA, Fatemi H, Tarlatzis B, et al. Live birth rates after transfer of equal number of blastocysts and cleavage stage embryos in IVF. A systematic review and meta-analysis. Hum Reprod 2008;23:91–9.
  33. Thomas MR, Sparks AE, Ryan GL, van Voorhis BJ. Clinical predictors of human blastocyst formation and pregnancy after extended embryo culture and transfer. Fertil Steril 2010;94:543–8.
  34. Dessolle L, Freour T, Barriere P, Darai E, Ravel C, Jean M, et al. A cycle-based model to predict blastocyst transfer cancellation. Hum Reprod 2010;25:598–604.
  35. Kaser DJ, Farland LV, Missmer SA, Racowsky C. Prospective study of automated versus manual annotation of early time-lapse markers in the human preimplantation embryo. Hum Reprod 2017;32:1604–11.
  36. Kirkegaard K, Kesmodel US, Hindkjær JJ, Ingerslev HJ. Time-lapse parameters as predictors of blastocyst development and pregnancy outcome in embryos from good prognosis patients: a prospective cohort study. Hum Reprod 2013;28:2643–51.
  37. Milewski R, Kuc P, Kuczynska A, Stankiewicz B, qukaszuk K, Kuczynski W. A predictive model for blastocyst formation based on morphokinetic parameters in time-lapse monitoring of embryo development. J Assist Reprod Genet 2015;32:571–9.
  38. Mersereau J, Stanhiser J, Coddington C, Jones T, Luke B, Brown MB. Patient and cycle characteristics predicting high pregnancy rates with single-embryo transfer: an analysis of the Society for Assisted Reproductive Technology outcomes between 2004 and 2013. Fertil Steril 2017;108:750–6.
  39. Stillman RJ, Richter KS, Banks NK, Graham JR. Elective single embryo transfer: a 6-year progressive implementation of 784 single blastocyst transfers and the influence of payment method on patient choice. Fertil Steril 2009;92:1895–906.
  40. Mullin CM, Fino ME, Talebian S, Krey LC, Licciardi F, Grifo J. Comparison of pregnancy outcomes in elective single blastocyst transfer versus double blastocyst transfer stratified by age. Fertil Steril 2010;93:1837–43.
  41. Sharara FI, Abdo G. Incidence of monozygotic twins in blastocyst and cleavage stage assisted reproductive technology cycles. Fertil Steril 2010;93:642–5.
  42. Sheiner E, Har-Vardi I, Potashnik G. The potential association between blastocyst transfer and monozygotic twinning. Fertil Steril 2001;75:217–8.
  43. Behr B, Fisch JD, Racowsky C, Miller K, Pool TB, Milki AA. Blastocyst-ET and monozygotic twinning. J Assist Reprod Genet 2000;17:349–51.
  44. da Costa AL, Abdelmassih S, de Oliveira FG, Abdelmassih V, Abdelmassih R, Nagy ZP, et al. Monozygotic twins and transfer at the blastocyst stage after ICSI. Hum Reprod 2001;16:333–6.
  45. Tarlatzis BC, Qublan HS, Sanopoulou T, Zepiridis L, Grimbizis G, Bontis J. Increase in the monozygotic twinning rate after intracytoplasmic sperm injection and blastocyst stage embryo transfer. Fertil Steril 2002;77:196–8.
  46. Knopman J, Krey LC, Lee J, Fino ME, Novetsky AP, Noyes N. Monozygotic twinning: an eight year experience at a large IVF center. Fertil Steril 2010;94:502–10.
  47. Milki AA, Jun SH, Hinckley MD, Behr B, Giudice LC, Westphal LM. Incidence of monozygotic twinning with blastocyst compared to cleavage-stage transfer. Fertil Steril 2003;79:503–6.
  48. Vitthala S, Gelbaya TA, Brison DR, Fitzgerald CT, Nardo LG. The risk of monozygotic twins after assisted reproductive technology: a systematic review and meta-analysis. Hum Reprod Update 2009;15:45–55.
  49. 49. Chang HJ, Lee JR, Jee BC, Suh CS, Kim SH. Impact of blastocyst transfer on offspring sex ratio and the monozygotic twinning rate: a systematic review and meta-analysis. Fertil Steril 2009;91:2381–90.
  50. Song B, Wei ZL, Xu XF, Wang X, He XJ, Wu H, et al. Prevalence and risk factors of monochorionic diamniotic twinning after assisted reproduction: A six-year experience base on a large cohort of pregnancies. PLoS One 2017;12:e0186813.
  51. Moayeri SE, Behr B, Lathi RB, Westphal LM, Milki AA. Risk of monozygotic twinning with blastocyst transfer decreases over time: an 8-year experience. Fertil Steril 2007;87:1028–32.
  52. Papanikolaou EG, Fatemi H, Venetis C, Donoso P, Kolibianakis E, Tournaye H, et al. Monozygotic twinning is not increased after single blastocyst transfer compared with single cleavage-stage embryo transfer. Fertil Steril 2010;93:592–7.
  53. Knopman JM, Krey LC, Oh C, Lee J, McCaffrey C, Noyes N. What makes them split? Identifying risk factors that lead to monozygotic twins after in vitro fertilization. Fertil Steril 2014;102:82–9.
  54. Skiadas CC, Missmer SA, Benson CR, Gee RE, Racowsky C. Risk factors associated with pregnancies containing a monochorionic pair following assisted reproductive technologies. Hum Reprod 2008;23:1366–71.
  55. Franasiak JM, Dondik Y, Molinaro TA, Hong KH, Forman EJ, Werner MD, et al. Blastocyst transfer is not associated with increased rates of monozygotic twins when controlling for embryo cohort quality. Fertil Steril 2015;103:95–100.
  56. Menezo YJR, Chouteau J, TorelloMJ, Girard A, Veiga A. Birth weight and sex ratio after transfer at the blastocyst stage in humans. Fertil Steril 1999;72:221–4.
  57. Luna M, Duke M, Copperman A, Grunfeld L, Sandler B, Barritt J. Blastocyst embryo transfer is associated with a sex-ratio imbalance in favor of male offspring. Fertil Steril 2007;87:519–23.
  58. Kausche A, Jones GM, Trounson AO, Figueiredo F, MacLachlan V, Lolatgis N. Sex ratio and birth weights of infants born as a result of blastocyst transfers compared with early cleavage stage embryo transfers. Fertil Steril 2001;76:688–93.
  59. Wilson M, Hartke K, Kiehl M, Rodgers J, Brabec C, Lyles R. Integration of blastocyst transfer for all patients. Fertil Steril 2002;77:693–6.
  60. Mittwoch U. Blastocysts prepare for the race to male. Hum Reprod 1993;8:1550–5.
  61. Luke B, Brown MB, Grainger DA, Baker VL, Ginsburg E, Stern JE. The sex ratio of singleton offspring in assisted-conception pregnancies. Fertil Steril 2009;92:1579–85.
  62. Li Z, Wang YA, Ledger W, Edgar DH, Sullivan EA. Clinical outcomes following cryopreservation of blastocysts by vitrification or slow freezing: a population-based cohort study. Hum Reprod 2014;29:2794–801.
  63. Liebermann J. Vitrification of human blastocysts: an update. Reprod Biomed Online 2009;19:4328.
  64. Wong KM,Mastenbroek S, Repping S. Cryopreservation of human embryos and its contribution to in vitro fertilization success rates. Fertil Steril 2014;102:19–26.
  65. Roy TK, et al. Single-embryo transfer of vitrified-warmed blastocysts yields equivalent live-birth rates and improved neonatal outcomes compared with fresh transfers. Fertil Steril 2014;1025:1294–301.
  66. Youm HS, Choi JR, Oh D, Rho YH. Closed versus open vitrification for human blastocyst cryopreservation: A meta-analysis. Cryobiology 2017;77:64–70.
  67. Schiewe MC, et al. Human blastocyst toxicity potential of different vitrification solutions: experiment II. Reprod Biomed Online 2016;13:e4–5.
  68. Kallen B, Finnstrom O, LindhamA, Nilsson E, Nygren K-G, Olausson OP. Blastocyst versus cleavage stage transfer in in vitro fertilization: differences in neonatal outcome? Fertil Steril 2010;94:1680–3.
  69. Dar S, Lazer T, Shah PS, Librach CL. Neonatal outcomes among singleton births after blastocyst versus cleavage stage embryo transfer: a systematic review and meta-analysis. Hum Reprod Update 2014;20:439–48.
  70. Cox GF, Burger J, Lip V, Mau UA, Sperling K, Wu BL, et al. Intracytoplasmic sperm injection may increase the risk of imprinting defects. Am J Hum Genet 2002;71:162–4.
  71. DeBaun MR, Niemitz L, Feinberg AP. Association of in vitro fertilization with Beckwith-Weidemann syndrome and epigenetic alterations of LIT1 and H19. Am J Hum Genet 2003;72:156–60.
  72. Gicquel C, Gaston V, Mandelbaum J, Siffroi JP, Flahault A, Le Bouc YL. In vitro fertilization may increase the risk of Beckwith-Weidemann syndrome related to the abnormal imprinting of the KCNQ10T gene. Am J Hum Genet 2003;72:1338–41.
  73. Maher ER, Brueton LA, Bowdin SC, Luharia A, Cooper W, Cole TR, et al. Beckwith-Weidemann syndrome and assisted reproductive technology (ART). J Med Genet 2003;40:62–4.
  74. Moll AC, Imhof SM, Cruysberg JR, Schouten-vanMeeteren AY, Boers M, van Leeuwen FE. Incidence of retinoblastoma in children born after in vitro fertilisation. Lancet 2003;36:309–10.
  75. Lidegaard O, Pinborg A, Andersen AN. Imprinting diseases and IVF: Danish National IVF cohort study. Hum Reprod 2005;20:950–4.
  76. Santos F, Hyslop L, Stojkovic P, Leary C, Murdoch A, Reik W, et al. Evaluation of the epigenetic marks in human embryos derived from IVF and ICSI. Hum Reprod 2010;00:1–9.
  77. Nelissen EC, Van Montfoort AP, Coonen E, Derhaag JG, Geraedts JP, Smits LJ, et al. Further evidence that culture media affect perinatal outcome: findings after transfer of fresh and cryopreserved embryos. Hum Reprod 2012;27:1966–76.
  78. Alikani M, Go KJ, McCaffrey C, McCulloh DH. Comprehensive evaluation of contemporary assisted reproduction technology laboratory operations to determine staffing levels that promote patient safety and quality care. Fertil Steril 2014;102:1350–6.
  79. Maas DHA, Storey B, Mastroianni L Jr. Oxygen tension in the oviduct of the rhesus monkey (macaca mulatta). Fertil Steril 1976;27:1312–7.
  80. Mastroianni L Jr, Jones R. Oxygen tension in the rabbit fallopian tube. J Reprod Fertil 1965;9:99.
  81. Waldenstrom U, Engstrom A-B, Hellberg D, Nilsson S. Low-oxygen compared with high-oxygen atmosphere in blastocyst culture, a prospective randomized study. Fertil Steril 2009;91:2461–5.
  82. Meintjes M, Chantillis SJ, Douglas JD, Rodriguez AJ, Guerami AR, Bookout DM, et al. A controlled randomized trial evaluating the effect of lowered incubator oxygen tension on live births in a predominantly blastocyst transfer program. Hum Reprod 2009;24:300–7.

Practice Documents

ASRM Practice Documents have been developed to assist physicians with clinical decisions regarding the care of their patients.
PracticeDocument_Teaser.webp

The use of preimplantation genetic testing for aneuploidy: a committee opinion (2024)

PGT-A use in the U.S. is rising, but its value as a routine IVF screening test is unclear, with mixed results from various studies.
PracticeDocument_Teaser.webp

Evidence-based diagnosis and treatment for uterine septum: a guideline (2024)

To provide evidence-based recommendations regarding the diagnosis and effectiveness of surgical treatment of a uterine septum.
PracticeDocument_Teaser.webp

The use of hormonal contraceptives in fertility treatments: a committee opinion (2024)

Hormonal contraception aids in the timing of ART cycles, reduce ovarian cysts at IVF cycle initiation, and optimize visualization before hysteroscopy.
Practice Committee Documents teaser

Current evaluation of amenorrhea: a committee opinion (2024)

Amenorrhea is the absence or abnormal cessation of the menses.

More Resources

MAC 2021 teaser
ASRM Academy on the Go

ASRM MAC Tool 2021

The ASRM Müllerian Anomaly Classification 2021 (MAC2021) includes cervical and vaginal anomalies and standardize terminology within an interactive tool format.

View the MAC Tool
EMR Phrases teaser
Practice Guidance

EMR Shared Phrases/Template Library

This resource includes phrases shared by ASRM physician members to provide a template for individuals to create their own EMR phrases.

View the library
Practice Committee Documents teaser

ASRM Practice Documents

These guidelines have been developed by the ASRM Practice Committee to assist physicians with clinical decisions regarding the care of their patients.

View ASRM Practice Documents
Ethics Committee teaser

ASRM Ethics Opinions

Ethics Committee Reports are drafted by the members of the ASRM Ethics Committee on the tough ethical dilemmas of reproductive medicine.

View ASRM Ethics Opinions
Coding Corner general teaser
Practice Guidance

Coding Corner Q & A

The Coding Corner Q & A is a list of previously submitted and answered questions from ASRM members about coding. Answers are available to ASRM Members only.

View the Q & A
Covid-19 teaser
Practice Guidance

COVID-19 Resources

A compendium of ASRM resources concerning the Novel Corona virus (SARS-COV-2) and COVID-19.

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Patient Resources

ReproductiveFacts.org provides a wide range of information related to reproductive health and infertility through patient education fact sheets, infographics, videos, and other resources.

View Website

Topic Resources

View more on the topic of embryo transfer
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How to bill for an FET

Is there a new update to the 89272 code that allows its use without View the Answer
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Fertility and Sterility On Air - TOC: August 2024

Stay informed with Fertility and Sterility On Air, discussing the latest research on reproductive medicine, obesity, Turner syndrome, and cutting-edge fertility treatments. Listen to the Episode
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Billing Physician vs Service Physician

What physician’s name must be on the treatment notes and who we are permitted to bill to insurance for:   View the Answer
Videos Icon

Journal Club Global: SREI Fellows Retreat - Fellows vs Faculty Debate: Luteal Support in Programmed FET Cycles

Fertility and Sterility Journal Club debate on progesterone administration in frozen embryo transfers, featuring faculty vs fellows discussing IM vs vaginal routes. View the Video
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Fertility and Sterility On Air - Live from ESHRE 2024: Part 2

Explore fresh embryo transfers, progesterone elevation, and day-seven embryo utility from experts at ESHRE 2024. Cutting-edge fertility insights await! Listen to the Episode
Coding Icon

Who to bill for gestational carrier services if intended parents have insurance?

I wanted to inquire about guidelines for billing services to a surrogate’s insurance company if intended parents purchased the insurance coverage.  View the Answer
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Fertility and Sterility On Air - TOC: June 2024

Covering articles on embryo transfer, PIEZO-ICSI, pregnancy outcomes, oocyte maturity, estradiol levels, and ovarian carcinoma and more! Listen to the Episode
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Fertility and Sterility On Air - TOC: May 2024

Topics this month include Iatrogenic and demographic determinants of the national plural birth increase, outcomes between ICSI and IVF with PGT-A. Listen to the Episode
Coding Icon

Coding for an endometrial biopsy/Mock cycle

We had patients request us to bill their insurance for the two monitoring visits and the Endo BX and change the diagnosis code to something that is payable.  View the Answer
PR Bulletin Icon

IVF-assisted pregnancies constitute 2.5% of all births in 2022

In 2022, the number of babies born from IVF increased from 89,208 in 2021 to 91,771 in 2022. This means that 2.5% of births in the US are a result of ART.

View the Press Release
Videos Icon

Journal Club Global - Actualización en la suplementación con progesterona en fase lútea para transferencias de embriones congelados

Efectividad del rescate de progesterona en mujeres que presentan niveles bajos de progesterona circulante alrededor del día de la transferencia de embriones View the Video
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Journal Club Global: Transferencia de embriones frescos versus congelados: ¿Cuál es la mejor opción

Los resultados de nuevas técnicas de investigación clínica que utilizan información de bancos nacionales de vigilancia médica.   View the Video
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US Embryo Transfer

At the meeting, we learned about the CPT code 76705-Ultasound guidance for embryo transfer, can this code be billed with CPT code 76942? View the Answer
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US Embryo Transfer in Surgery Center

Can we use code 76998 for the ultrasound guidance as this patient is being seen in the Surgery Center? View the Answer
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US Embryo Transfer-Transmyometrial

How would you code for an ultrasound- guided transvaginal-transmyometrial test transfer of embryo catheter? View the Answer
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Uterine Sounding

Is there any specific CPT code(s) for uterine sounding? (Referring to cannulating the cervix and “sounding” or measuring the uterine height)  View the Answer
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CPT 89253 and 89254 for Assisted hatching

Can I bill CPT codes 89253 and 89254 together? If yes, do I need a modifier on any of the codes? View the Answer
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Trial Transfer

Can you advise the proper coding process for a trial transfer? View the Answer
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IVF Lab vs Physician Practice Billing

We are planning to open an IVF lab that is not contracted with insurance companies. View the Answer
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Monitoring FET

What is the correct diagnosis code to use on the follicle ultrasound (76857) for a patient who is undergoing frozen embryo transfer (FET)? View the Answer
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In Vitro Maturation

Have CPT codes been established for maturation in vitro? View the Answer
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Endometrial Biopsy/Scratch

What CPT code should be used for a “scratch test”?  View the Answer
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Embryo Thawing/Warming

Is it allowable to bill 89250 for the culture of embryos after thaw for a frozen embryo transfer (FET) cycle? View the Answer
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D&C Under Ultrasound Guidance

What are the CPT codes and ICD-10 codes for coding a surgical case for a patient with history of Stage B adenocarcinoma of the cervix ... View the Answer
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Elective Single Embryo Transfer

Has any progress been made in creating/obtaining a specific CPT code for an elective single embryo transfer (eSET)?  View the Answer
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Assisted Hatching Billed With Embryo Biopsy

Do you know if both assisted hatching (89253) and embryo biopsy for PGS/PGD/CCS (89290/89291) can be billed during the same cycle?  View the Answer
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Embryo Transfer

A summary of Embryo Transfer codes collected by the ASRM Coding Committee View the Coding Summary
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Journal Club Global Live from PCRS - Non-Invasive Embryo Selection Techniques

The next great frontier in reproductive medicine is how to non-invasively select an embryo with the highest reproductive potential for transfer. View the Video
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Journal Club Global - Should Fellows Perform Live Embryo Transfers in Fellowship?

Few things are more taboo in reproductive medicine fellowship training than allowing fellows to perform live embryo transfers. View the Video
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Journal Club Global Live from ASRM - Optimal Management of the Frozen Embryo Transfer Cycle: Insights From Recent Literature

Three recent papers published in the Fertility and Sterility family of journals, all explore different aspects of optimizing frozen embryo transfer cycles. View the Video
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Guidance on the limits to the number of embryos to transfer: a committee opinion (2021)

ASRM's guidelines for the limits on the number of embryos to be transferred during IVF cycles have been further refined ... View the Committee Opinion
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Compassionate transfer: patient requests for embryo transfer for nonreproductive purposes (2020)

A patient request to transfer embryos into her body in a location or at a time when pregnancy is highly unlikely ... View the Committee Opinion
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Blastocyst culture and transfer in clinically assisted reproduction: a committee opinion (2018)

The purposes of this document is to review the literature regarding the clinical application of blastocyst transfer. View the Committee Opinion
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Transferring embryos with genetic anomalies detected in preimplantation testing: an Ethics Committee Opinion (2018)

Patient requests for transfer of embryos with genetic anomalies linked to serious health-affecting disorders detected in preimplantation testing are rare but do exist. View the Committee Document
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ASRM standard embryo transfer protocol template: a committee opinion (2017)

Standardization improves performance and safety of embryo transfer View the Committee Opinion
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Performing the embryo transfer: a guideline (2017)

A systematic review of the literature was conducted which examined each of the major steps of embryo transfer. Recommendations made for improving pregnancy rates are based on interventions demonstrated to be either beneficial or not beneficial. (Fertil Steril® 2017;107:882–96. ©2017 by American Society for Reproductive Medicine.) View the Committee Guideline