Skip to Content
Home > Wellness > Health Library > Trimester
Browse and register for related classes.
A normal pregnancy lasts about 40 weeks from the first day of your last menstrual period to the
birth of a baby. This time is roughly divided into 3 periods: the first
trimester, from the first day of your last menstrual period to about the 12th week of pregnancy; the second
trimester, from about 13 to 27 weeks of pregnancy; and the third trimester,
from about 28 weeks of pregnancy until birth.
Each trimester of pregnancy is marked by developmental changes in
Current as of:
May 22, 2015
Sarah Marshall, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
250 Pleasant Street
Concord, NH 03301
Contact Concord Hospital
View Quality Data
© 2016 Concord Hospital