"Pregnancy brain" makes it impossible to concentrate.
This may be true in the first few months, when a 30-fold increase in progesterone makes most women really, really, sleepy. And some researchers say pregnancy hormones may make it hard for a pregnant woman to remember where she placed her keys.
But pregnancy brain may not be all bad.
In a small pilot study of 10 women, Stone and colleagues found that women tend to have increased attention spans in their third trimester. If the results are confirmed in a larger group of women something the researchers are currently working on it may be an indicator of "neuronal nesting."
"This may be nature's way of increasing the attention a mother is going to need to give a newborn," Stone said.