Twin pregnancy after vitrification of 2-pronuclei human embryos.
OBJECTIVE
To report an ongoing twin pregnancy after transfer of embryos that were vitrified at the 2-pronuclei stage in a new vitrification solution.


METHODS
Case report.


METHODS
A tertiary-care infertility clinic.


METHODS
A 26-year-old infertile woman in whom two previous IVF implantations failed.


METHODS
Vitrification of 2-pronuclei embryos, in vitro culture for 48 hours, and transfer into the uterus.


METHODS
Survival and cleavage after vitrification and achievement of clinical pregnancy.


RESULTS
Six zygotes were vitrified by using a three-step protocol (4% ethylene glycol for 3 minutes, 20% ethylene glycol for 1 minute, and 38% ethylene glycol and 1.2 M trehalose for 0.5 minute). After 2 months of storage in a double-straw system in liquid nitrogen, two zygotes were warmed and cryoprotectants were removed by using a four-step protocol (1 M, 0.5 M, 0.25 M, and 0.125 M of trehalose). Two embryos were transferred after 48 hours of in vitro culture, cleaving to 5 and 6 cells. The resulting twin pregnancy was confirmed by ultrasonography at the sixth week.


CONCLUSIONS
Vitrification by using ethylene glycol and trehalose appears to be a safe, promising method for cryopreservation of human zygotes. Storage of vitrified zygotes in a double-straw system does not compromise their subsequent potential for survival and development.
Jelinkova
Ladislava
L
Christian-Lauritzen-Institut, Frauenstrasse 51, 89073 Ulm, Germany. ljeli@seznam.cz
Selman
Helmy A
HA
Arav
Amir
A
Strehler
Erwin
E
Reeka
Natalie
N
Sterzik
Karl
K
D000328:Adult; D015925:Cryopreservation / Q000379:methods; D003451:Cryoprotective Agents; D004624:Embryo Transfer; D019855:Ethylene Glycol / Q000494:pharmacology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014199:Trehalose / Q000494:pharmacology; D014427:Twins
D003451:Cryoprotective Agents; D014199:Trehalose; D019855:Ethylene Glycol