Prenatal vitamins

Hilda
Has anyone ever had an issue with prenatal vitamins? I'm not sure if it's the pregnancy or the pills that gave me bad diarrhea today. I looked at the label on them and they have 300% of my daily iron requirement. I've been taking them for the last week and a half. I'm worried I might be hurting the little chocolate chip in my belly- I'm six weeks pregnant tomorrow.