Anyone taking vitamins with DHA?

Luciana
My Doctor said that baby's tend to grow more than average if taking DHA in prenatal vitamins . I went for my 20 weeks Ultrassound and baby boy weight is 566g (20oz) and he was supposed to be around 300g. So he is very big. I'm wondering if this will make my delivery harder . Should I switch for a prenatal vitamin without DHA?