when is second trimester

The second trimester usually runs from about week 13 or 14 of pregnancy up to the end of week 26 or 27, roughly covering months 4, 5, and 6 of pregnancy.

If you conceived naturally and count from the first day of your last menstrual period (how doctors usually date pregnancy), that means:

• First trimester: up to 12–13 weeks.

• Second trimester: about 13/14 weeks to 26/27 weeks.

• Third trimester: starts around week 27/28 until birth.

Because different organizations use slightly different cutoffs, some say 13–26 weeks and others 14–27 weeks, but all place the second trimester squarely in the middle third of pregnancy.