TMI Dark Area During Pregnancy

30 weeks pregnant with my first child and I noticed today my vagina and butt crack area are Dark! Is this normal during pregnancy? Will my dark areas go back to the original color? Or will my dark areas stay this way? This is a little embarrassing for me. And I know underwears are not the problem I stopped using underwears before my pregnancy. All I use are panty liners when I where my pants/jeans. Has anyone experiance this before ? TIA.