Table 2. The birth rate of vitrified–warmed oocytes derived from IVF with NAC.

NAC (mM)	Oocyte	Number of transferred two-cell embryos	Number of recipients	Number of live pups (%)
0	Fresh	80	4	31 (38.8 ± 16.5)
0	Vitrified–warmed	80	4	32 (40.0 ± 15.8)
0.5	Vitrified–warmed	80	4	37 (46.3 ± 11.1)

Two-cell embryos were transferred in each oviduct of the recipient mice (20 embryos/recipient), and the number of pups was recorded after 19 days. Two-cell embryos derived from fresh oocytes were used as controls. The birth rate was calculated as follows: (Number of the pups / Number of transferred two-cell embryos) × 100. Results are expressed as mean ± SD (n = 4).