Prenatal vitamins before pregnancy?

Annamaria

What do you ladies think about taking prenatal vitamins before even being pregnant. Im 37 TTC baby #1 Dr advised I can start taking prenatal vitamins but they cause me and sorry for this ...nothing but constipation! 😩😳 Help should I avoid them before being preggers? And start then? If not what brands do u suggest would be best for that issue. I'm thinking they have too much iron for me!