1. No she uses a more permanent type transformation to hide her age, Which wears away when she has no chakra. (So techinically Naruto too can get prego as he can transform into a girl)
2. Very low chance as usually women get their menopause at about forty years. Show one woman who is over fifty and shriveled and yet had children? Also Tsunade's real body is more or less shriveled wld create complications.
3. Get ur facts right first:
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If u read u will know that only a select few cld awaken the Sharingan. Also Tsunade dont have her grandad's Mokuton: So it proves that blood always dont matter. So there is no certainity.