My MIL told me to forget about taking a shower or washing my hair one month after giving birth or I will be plagued by headaches and rheumatism for the rest of my life. Any truth to this?

I couldn't even resist not to take a bath for 24 hours! I beg my nurse to let me shower 2 hours after giving birth but they said to wait until overnight :) My opinion, shower is good for your sanitary, if you afraid of any headaches or rheumatism, control the heat. You can shower with warm water or you can simply take a bath without wash your hair (or maybe not doing it every time you shower. 3 times a week might be good)