In the first phase, the oogonium has little cytoplasm and bigger nuclear-cytoplasmic ratio.

第1时相，卵原细胞细胞，大。

The proliferative phase of the oogonium was found in the gestational age between 41d and 84d.

卵原细胞增殖期为41-84天胎龄间，而增殖高峰在41-48天间出现。