How many months pregnant are you if you are 21 weeks?
Since most doctors calculate based on how many weeks along you
are starting from your Last Known Mental Period (LMP), it can be
confusing converting weeks into months.
So here's a basic rundown: Normal pregnancy lasts 280 days from
your LMP (or, 40 weeks), or roughly 266 days from conception (which
happens AFTER the LMP) to birth (or, 38 weeks).
Here is a simple breakdown of weeks to months to help keep you
on track: Weeks 1-4 - Month One (First Trimester) Weeks 5-8 - Month
Two (First Trimester) Weeks 9-13 Month Three (First Trimester)
Weeks 14-17 Month Four (Second Trimester) Weeks 18-21 Month Five
(Second Trimester) Weeks 22-26 Month Six (Second Trimester) Weeks
27-30 Month Seven (Third Trimester) Weeks 31-35 Month Eight (Third
Trimester) Weeks 36-40+ Month Nine (Third Trimester)