For some women, pregnancy brain fog starts as early as the first trimester. For others, it may not start until later in the pregnancy. There is no one answer to this question since every woman’s experience with pregnancy brain fog is different.
Many women find that their brain fog clears up after they give birth. However, for some women it can persist for a while after giving birth. If you are still experiencing cognitive problems after giving birth, be sure to talk to your doctor about it.