prenatal vitamins with or without DHA

Summer
Does your prenatal vitamins have DHA in it?  The ones prescribed by my Dr does not and I asked him during first tri and he said I did not need DHA but I just read an article saying I should have been taking DHA. I'm 36w now. I'm going to CVS to get some vitamins with DHA hopefully it's not too late?  I'm upset he told me I didn't need it