Yes, The volume of your brain cells actually decreases during the third trimester. There is no research to back that up as a recently research doubt about that but talking to pregnancy mothers and being once in that position, I do agree with this. According to the doctors there are 15 to 40 times more progesterone and estrogen marinating the brain during pregnancy and when you are not getting enough sleep and are multitasking, nobody's memory is good.
A little forgetfulness is understandable like the feeling of walking into a room, going after something, and not remembering what you went for but don't worry - this is only temporary and levels should bounce back to normal after birth.
If after delivery you keep forgetting things it is better to see your doctor.
