Great question!
I have fish oil at home, but haven't been taking them. I have seen studies regarding fish oil and improved brains in babys, when mum takes them while pregnant, and particularly when breastfeeding. I couldnt find specifics n when to take them, but I know what seems like a high dose is normal. I do remember reading not to take them late in third trimester as I think there is an increased chance of bleeding. Dont quote me on this- I should have looked it up properly first. Do a google search on it.