Evening Primrose affects hormones, which is why it's not advised until the very end of pregnancy.
Fish oils are a MUST for baby's brain and neuron development, among other things. The problem finding a good one are many, however:
-- Pregnant tummies are sensitive
-- Many are already rancid when on the shelf
-- Pregnant tummies are sensitive
-- Even if the oil itself is free of contaminates the capsule ingredients can be very bad
-- Pregnant tummies are sensitive
I used to take one that was reliably free of contaminates, but the capsules "may include pthalates" which could cause defects (specifically genital ones, in boys, and I'm having a boy) so while Daddy got to keep taking that brand until he was done with the bottle, I was told to quit.
I burped and vomited up a bunch of others, even though my morning sickness was pretty mild.
My naturopath put me on Nordic Naturals Pro-Omega (the Prenatal isn't necessary). The other tip was to put the capsules in the freezer, and take 2 before a meal. Then I almost never burped it back up. And when I did, since the oil wasn't rancid and had a lemon flavor, it didn't bother me.