Comparison of cryopreservation of supernumerary pronuclear human oocytes obtained after intracytoplasmic sperm injection (ICSI) and after conventional in-vitro fertilization.
A comparison was made of pronuclear stage human oocytes obtained either after classical in-vitro fertilization (IVF) or after intracytoplasmic sperm injection (ICSI). After ICSI or IVF, three fertilized oocytes from each patient were kept in culture for a further 24 h before embryo transfer. The surplus oocytes were cryopreserved using the 'open freezing system' and 1,2-propanediol and sucrose as cryoprotectants. A cohort of 817 and 1626 oocytes in pronuclear stage were frozen after IVF and ICSI respectively. Of these, 333 and 744 zygotes have been thawed, of which 78 and 76.5% were morphologically intact zygotes after IVF and ICSI respectively. From the 204 (ICSI) and 89 (IVF) zygote transfers performed, 34 (17%) and 18 (20%) pregnancies were established. Both groups showed a similar abortion rate of approximately 20%. It is concluded that pronuclear stage oocytes resulting from ICSI can be successfully frozen/thawed and the survival and pregnancy rates achieved are comparable to those for zygotes obtained after IVF.
al-Hasani
S
S
Medical University of Lübeck, Department of Obstetrics and Gynecology, Germany.
Ludwig
M
M
Gagsteiger
F
F
Küpker
W
W
Sturm
R
R
Yilmaz
A
A
Bauer
O
O
Diedrich
K
K
D015925:Cryopreservation / Q000379:methods*; D003593:Cytoplasm; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D008845:Microinjections; D009865:Oocytes; D011247:Pregnancy; D011256:Pregnancy Outcome; D013094:Spermatozoa; D015053:Zygote