Hair change !!!!

Help !!! My hair use to be super curly pretty much my whole life even with straightening in my teens years but every since I got pregnant with my daughter 5 years ago my hair had changed !!!! So while pregnant with her I went on a no heat strike(b.c I was to lazy to do my hair ) so I always left it natural without products. And I started to notice my hair become less curly fast forward to now the same thing happened again while pregnant with my son 9 months ago but there was a BIG change ! My hair is just wavy now with pretty much no curl pattern left and it’s very sad lol.... has this happened to anyway I the only one who experienced drastic hair change during and after birth? HELP