Kishimoto is known for adding mythological elements for the series. As the Uchiha Clan's moves are based off Japan's mythological gods. And how Kushina, Mikoto and Fugaku, are named after gods.

Sakura is loosely based of Konohasakuya-hime.

In chapter 50 she holds a mirror and comb.

Couldn't find the original one.

Which is a prominent feature of Konohasakuya-hime. Konohasakuya-hime is a blossom princess princess and the cherry blossom is her symbol. She also controls the volcanoes and erupts when she's upset which can allude to Sakura's fiery temper. Sakura has the ability to heal others, Konohasakuya-hime is the avatar of life.

In various covers Sakura is by the beach, which was where Konohasakuya-hime met Nigni-no-Mikoto (Who Sasuke is said to be loosely based off)

Nigini-no-Mikoto and Sasuke both wield the Kusanagi blade. 

Nigni-no-Mikoto was offered a different bride but has hid mind set on marrying Konohasakuya-hime, similar to Sasuke's loyalty to Sakura.

Sarada is named after the god Saraswati, the goddess of knowledge.

Its possible that the Gaiden was loosely based off the Konhasakuya-hime tale's when there was question of their child's parentage which made the mother upset. Both mothers are protective of their children.

-LunaKingdom