Journal of Assisted Reproduction and Genetics

, Volume 24, Issue 4, pp 119–123

Natural cycle cryo-thaw transfer may improve pregnancy outcome

  • Vadim Morozov
  • Jane Ruman
  • Daniel Kenigsberg
  • Glenn Moodie
  • Steven Brenner
Assisted Reproduction


Objective: To compare natural vs. hormone replacement treatment (HRT) for cryo-thaw embryo transfer cycles in patients with frozen embryos from previous ART. Design and Settings: Retrospective chart review of 164 patients (242 cycles) who underwent natural or HRT cryo-thaw embryo transfer between January 2002 and April 2005. Main Outcome Measures: Pregnancy rates per transfer in natural and HRT cryo-thaw cycles. Results: The pregnancy rate per transfer was higher with natural cycles (36.76% vs. 22.99%, P = 0.0298). There was no statistical difference in mean age, endometrial thickness, and average embryo quality in successful cycles. Mean endometrial thickness prior to transfer was greater in natural cycles (9.95 vs. 8.89 mm, P < 0.001). Mean serum estradiol levels were higher in the HRT group prior to transfer (526.1 vs. 103.8 pg/ml, P < 0.001), and were found to be lower in women who achieved pregnancy (337.1 vs. 433.3 pg/ml, P = 0.0136). Conclusion: Hormone replacement in preparation for cryo-thaw transfer of embryos was found to be associated with decreased pregnancy rates in comparison to natural cycle cryo-thaw transfer. Greater endometrial thickness was achieved with lower serum estradiol levels in patients undergoing natural cycles, suggesting that higher estradiol levels during HRT cycle may interfere with the window of implantation.


Cryo-thaw cycle Natural HRT 


  1. 1. Scholar
  2. 2.
    Wang JX, Yap YY, Matthews CD. Frozen-thawed embryo transfer: influence of clinical factors on implantation rate and risk of multiple conception. Hum Reprod 2001;16(11):2316–9PubMedCrossRefGoogle Scholar
  3. 3.
    Dickey RP, Olar TT, Curole DN, Taylor SN, Rye PH. Endometrial pattern and thickness associated with pregnancy outcome after assisted reproductive technologies. Hum Reprod 1992;7(3):418–21PubMedGoogle Scholar
  4. 4.
    Noyes N, Liu HC, Sultan K, Schattman G, Rosenwaks Z. Endometrial Thickness appears to be a significant factor in embryo implantation in in-vitro fertilization. Hum Reprod 1995;10(4):919–22PubMedGoogle Scholar
  5. 5.
    Oehninger S, Mayer J, Muasher S. Impact of different clinical variables on pregnancy outcome following embryo cryopreservation. Mol Cell Endocrinol 2000;169(1–2):73–7PubMedCrossRefGoogle Scholar
  6. 6.
    Queenan JT Jr, Veeck LL, Seltman HJ, Muasher SJ. Transfer of cryopreserved-thawed pre-embryos in a natural cycle or a programmed cycle with exogenous hormonal replacement yields similar pregnancy results. Fertil Steril 1994;62(3):545–50PubMedGoogle Scholar
  7. 7.
    Sathanandan M, Macnamee MC, Rainsbury P, Wick K, Brinsden P, Edwards RG. Replacement of frozen-thawed embryos in artificial and natural cycles: A prospective semi-randomized study. Hum Reprod 1991;6(5):685–7PubMedGoogle Scholar
  8. 8.
    al-Shawaf T, Yang D, al-Magid Y, Seaton A, Iketubosin F, Craft I. Ultrasonic monitoring during replacement of frozen/thawed embryos in natural and hormone replacement cycles. Hum Reprod 1993;8(12):2068–74PubMedGoogle Scholar
  9. 9.
    Tanos V, Friedler S, Zajicek G, Neiger M, Lewin A, Schenker JG. The impact of endometrial preparation on implantation following cryopreserved-thawed-embryo transfer. Gynecol Obstet Invest 1996;41(4):227–31PubMedCrossRefGoogle Scholar
  10. 10.
    Loh SK, Leong NK. Factors affecting sussecc in an embryo cryopreservation programme. Ann Acad Med, Singapore 1999;28(2):260–5Google Scholar
  11. 11.
    Sathanandan M, Macnamee MC, Rainsbury P, Wick K, Brinsden P, Edwards RG. Replacement of frozen-thawed embryos in artificial and natural cycles: a prospective semi-randomized study. Hum Reprod 1991;6(5):685–7PubMedGoogle Scholar
  12. 12.
    Adams SM, Terry V, Hosie MJ, Gayer N, Murphy CR. Endometrial response to IVF hormonal manipulation: Comparative analysis of menopausal, down regulated and natural cycles. Reprod Biol Endocrinol 2004;2:21PubMedCrossRefGoogle Scholar
  13. 13.
    Ma WG, Song H, Das SK, Paria BC, Dey SK. Estrogen is a critical determinant that specifies the duration of the window of uterine receptivity for implantation. Proc National Acad Sci, USA 2003;100(5):2963–8CrossRefGoogle Scholar
  14. 14.
    Leal Almeida M, Saucedo de la Llata E, Batiza Resendiz V, Santos Haliscak R, Galache Vega P, Hernandez Ayup S. Endometrial thickness. Prognostic factor in assisted reproduction? [Spanish] Ginecologia y Obstetricia de Mexico 2004;72:116–9PubMedGoogle Scholar
  15. 15.
    Rashidi BH, Sadeghi M, Jafarabadi M, Tehrani Nejad ES. Relationships between pregnancy rates following in vitro fertilization or intracytoplasmic sperm injection and endometrial thickness and pattern. European J Obstetrics, Gynecol, Reprod Biol 2005;120(2):179–84CrossRefGoogle Scholar
  16. 16.
    Elizur SE, Lerner-Geva L, Levron J, Shulman A, Bider D, Dor J. Factors predicting IVF treatment outcome: a multivariate analysis of 5310 cycles. Reprod Biomed Online 2005;10(5):645–9PubMedCrossRefGoogle Scholar
  17. 17.
    Jansen RP. The effect of female age on the likelihood of a live birth from one in-vitro fertilisation treatment. Med J Australia 2003;178(6):258–61PubMedGoogle Scholar
  18. 18.
    Miles RA et al. Pharmacokinetics and endometrial tissue levels of progesterone after administration by intramuscular and vaginal routes: a comparative study. Fertil Steril 1994;62(3):485–90PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Vadim Morozov
    • 1
  • Jane Ruman
    • 1
  • Daniel Kenigsberg
    • 2
  • Glenn Moodie
    • 2
  • Steven Brenner
    • 1
  1. 1.Department of Obstetrics and GynecologyLong Island Jewish Medical Center, Long Island Campus of Albert Einstein College of Medicine of Yeshiva UniversityNew Hyde ParkUSA
  2. 2.John T. Mather Memorial HospitalPort JeffersonUSA

Personalised recommendations