When I was pregnant with PK, I was well into my second trimester before I started noticing the fact that my hair wasn't falling nearly as much as it used to. I was grateful because I normally shed like a cat, and hence it ended up EVERYWHERE! I shed so little hair that the only hair I'd find piling up in the bathroom was the hubby's hair, instead of mine. And extra bonus: my hair wasn't clogging up the bathtub anymore.
Right after PK was born, however, I noticed that my hair once again started to fall out at its normal rate. I counted myself lucky that I wasn't one of those women whose hair falls out in clumps post-partum. That is, until I started talking to other moms and found out that their hair started falling out like crazy at around the 3-month mark. Well, sure enough, the same thing happened to me. Now I shed enough hair to make a village of Barbie dolls VERY happy. I just hope that I don't end up with any bald spots. *knock on wood*