You may not feel as sharp as you did prior to pregnancy. In fact, 50-80% of women report some degree of memory change during pregnancy.* These symptoms are commonly referred to as momnesia or pregnant brain. We don't know the exact cause and research has not shown that actual cognitive deficits are occurring (which is a good thing), but it can be quite disturbing for moms and moms-to-be. There are a number of theories about why this occurs, including hormonal and change in brain size during pregnancy, which are discussed in my post 7 Strategies for managing forgetfulness during pregnancy and postpartum.
* Stadtlander, L. 2013. Memory and Perceptual Changes during Pregnancy. Int J Childbirth Education 28(2): 49-53.