What does it mean that Wuzi Japanese bed is really northwest?

This is the monthly and daily position of Liu Jia Fetal God recorded in the Yellow Calendar. It means: in the first month, the fetal god occupied the houses and beds in the northwest. On the day of Wuzi, pregnant women should not lose their manners in the position occupied by the fetal god, otherwise it will have a negative impact on the fetus. (Liu Jia refers to pregnant women; Indeed, we must talk about it; Northwest is the fetal position of Wuzi, and Daoism opens the door. )