Cryostorage duration does not affect pregnancy and neonatal outcomes: a retrospective single-centre cohort study of vitrified–warmed blastocysts. Issue 6 (June 2018)

• Record Type: Journal Article
• Authors: Ueno, Satoshi; Uchiyama, Kazuo; Kuroda, Tomoko; Yabuuchi, Akiko; Ezoe, Kenji; Okimura, Tadashi; Okuno, Takashi; Kobayashi, Tamotsu; Kato, Keiichi
• Is Part Of: Reproductive biomedicine online. Volume 36:Issue 6(2018)
• Page Start: 614
• Page End: 619
• Publication Date: 2018-06
• Subjects: Cryostorage duration -- Neonatal outcomes -- Single blastocyst transfer -- Open device vitrification system -- IVF; Human reproductive technology -- Periodicals; Human embryo -- Periodicals; Reproduction -- Periodicals; 616.692
• DOI: 10.1016/j.rbmo.2018.03.008
• Languages: English
• ISSNs: 1472-6483

Abstract

Abstract: A retrospective cohort study of 8736 autologous single vitrified–warmed blastocyst transfer cycles was conducted in a single centre to investigate the effect of cryostorage on clinical and neonatal outcomes. Cryostorage duration was classified into three groups: (A) 0–2 months ( n = 4702); (B) 2–13 months ( n = 2853) and (C) 13–97 months ( n = 1181). Blastocysts were vitrified using the Cryotop method. No significant differences were observed in live birth rates: (A) 37.3%; (B) 34.9%; (C) (35.2%). Gestational period was significantly shorter in group C: (A) 38.7 ± 1.8; (B) 38.6 ± 1.6; (C) 38.1 ± 1.7; P < 0.05. This was clinically unimportant as the average gestational age was more than 38 weeks. No significant differences between groups were observed in birth weight: (A) 3060 ± 455 g; (B) 3052 ± 449 g; (C) 2992 ± 445 g, or congenital malformation rates: (A) 2.2%; (B) 1.9%; (C) 1.8%. The limitation of this study was that maximum storage duration was 8 years; most blastocysts were in cryostorage for much shorter periods. Long-term storage of blastocysts that are vitrified using an open device vitrification system has no negative effect on pregnancy and neonatal outcomes.