Tsunade is the strongest female in Naruto.

[Neonian]

Also Mei. She's strong.

 

[Keimil]

Don't worry, Konan, Mei and Mito won't have higher stats than a Sannin- Hokage.

Maybe, but if you read what Hashirama said, Sakura is at least at Tsunade's level or above, or she will surpass her soon, besides Jiraya and Kakashi predicted she would surpass her in the firsts chapters. It's only matter of time.