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?

Believe it or not I obeyed my confinement nanny and did not bathe for 2 weeks. I could only wipe my body. After the first shower I enjoyed it so much that I continued with it. Maybe 20 years later we will be able to answer your question!