Q: We are in the middle of potty training our 2-year-old son, with our baby daughter due in six weeks. What can we expect?
A: In a word: regression. When the new baby arrives, much of your focus will be on her diapers--specifically, the pee and poop in those diapers. It can be hard for a toddler to see so much attention being showered on one family member's elimination habits at the same time that he is supposed to be "growing up" and giving up his diapers.
Even though many doctors recommend toilet training at age 2, I think it is OK to wait until your son is 3 or older. If you try to make large changes in his life--such as toilet training, moving him into a big bed or starting preschool--he may associate them with the new baby and resent her. It's far better to do things months in advance of the new baby--or, better still, months after.
I also suggest keeping toddler-size diapers and Pull-Ups handy: When you're driving with a "potty-trained" 2- to 2 1/2-year-old and he says, "Gotta pee," you've got a 60- to 90-second warning. So be prepared.