Should embryos developing to blastocysts on day 7 be cryopreserved and transferred an analysis of pregnancy and implantation rates

Capsule:
Embryos cryopreserved after reaching blastocyst stage on day 7 were compared to those cryopreserved on days 5 and 6. Day 7 blastocysts have lower but clinically important pregnancy rates.

Authors:
George Kovalevsky, M.D., Stacy M. Carney, B.A., Linda S. Morrison, M.B.A., Caitlin F. Boylan, B.S., Adrienne B. Neithardt, M.D., Ronald F. Feinberg, M.D., Ph.D.

Volume 100, Issue 4, Pages 1008-1012, October 2013

Abstract:

Objective:
To compare pregnancy rates (PRs) using blastocysts cryopreserved on day 7 with those cryopreserved ondays 5 and 6.

Design:
Retrospective observational cohort study.

Setting:
Infertility center performing IVF.

Patient(s):
Eight hundred women with infertility undergoing frozen ET.

Intervention(s):
Blastocysts cryopreserved on days 5, 6, and 7 after retrieval were thawed and transferred.

Main Outcome Measure(s):
Ongoing PRs (pregnancy developing appropriately into the second trimester). Thaw survival, implantation rates, and clinical PRs were also calculated.

Result(s):
A total of 1,406 embryos were thawed with a survival of 90.7% for day 5, 83.7% for day 6, and 78.7% for day 7. Implantation rates were 43.3%, 28.9%, and 28.9%, respectively. Ongoing PRs were 43.9%, 32.9%, and 26.7%, respectively.

Conclusion(s):
Blastocysts cryopreserved on day 7 have a lower, but clinically important potential. Embryos that do not achieve blastocyst stage on day 6 should not be universally discarded, but should be observed in culture 1 more day as 27% may result in an ongoing pregnancy.

Translate »