What is the ruling on going out in a loose dress that resembles an abaya and is suitable for pregnancy, with a calm color that does not attract attention, along with a covering hijab?

The Shar'i hijab does not require a specific color or form. Rather, it has conditions and regulations, among them: that it should not be eye-catching or an adornment in itself. There is no objection to wearing a dress if these conditions are met.