Pregnancy is not 10 months

A year has 52 weeks (12 months).
You are pregnant for 40 weeks (9 months).
You are not pregnant for 12 weeks (about 3 months).

The average month has 4.3 weeks in it.
If you are pregnant for 40 weeks, that comes to 9.3 months.
Which is like nine months and a week.
So don't count the first "pre-conception" days and you get nine months.
Even a 42 week pregnancy (from LMP) is still not 10 months.

http://www.babiesonline.com/articles/pregnancy/a10monthpregnancy.asp

I'm currently 19 weeks + 1 day so that means I'm 4 months pregnant...I won't be 5 months pregnant until 21 weeks + 4 days (April 6th). =)