parshanut torah comment - Why is Parshat Yitro not called Va'yishmah, after its first word?

Following the logic of previous Parshios: Vayishlach, Vayetze, Vayeshev, Vayigash etc Parshas Yitro should be called Vayishmah as it starts with "וַיִּשְׁמַע יִתְרוֹ כֹהֵן מִדְיָן".

Many other Parshiot do start with verbs, such as Vayeshev, Veytzeh, Vayigash, etc.

Why not?