How much Dha do you need while pregnant?

Heather
Hi ladies! Sorry this maybe a silly question but how much DHA did your doctor's recommend you to take? My prenatal used to contain it until there was a recall on them and I was told to buy it over the counter. I asked the pharmacist and she told me to take two pills (which servings per container said 2 pills) but the two pulls were 900mgs. I didn't know if that was way to much?