Vitrification of human hatched blastocysts: a report of 4 cases.
BACKGROUND
Vitrification is a fairly well-established technique for cryopreservation of human zona-intact blastocysts. However, little is known about the efficacy of the vitrification technique for zona-free hatched blastocysts.


METHODS
A total of 4 hatched blastocysts from 4 healthy, infertile women undergoing in vitro fertilization were vitrified and warmed. All 4 hatched blastocysts expanded after warming and were transferred to 4 patients. Three of the women became clinically pregnant. Two healthy infants were born in 2 deliveries, and 1 pregnancy had progressed to 35 weeks at this writing.


CONCLUSIONS
Our results suggest that vitrification is a useful cryopreservation technique not only for zona-intact blastocysts but also for zona-free hatched blastocysts.
Hiraoka
Kenichiro
K
Kinutani Women's Clinic, 2-1-4-3F, Ohtemachi, Naka-ku, Hiroshima 730-0051, Japan. hiraoka@chive.ocn.ne.jp
Hiraoka
Kaori
K
Kinutani
Masayuki
M
Kinutani
Kazuo
K
D000328:Adult; D001755:Blastocyst / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods; D046149:Embryo Culture Techniques; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy