when is the first trimester over

The first trimester of pregnancy is generally considered to be over at about 12–13 weeks of pregnancy, measured from the first day of your last menstrual period. Many medical sources and pregnancy organizations define it as lasting through the end of week 12 or up to 13 weeks and 6 days, with the second trimester starting around week 13–14.

Quick Scoop

• The first trimester usually runs from week 1 through the end of week 12 of pregnancy.

• Some doctors and guides say it ends at 12 weeks, others at 13 weeks and 6 days, so you may see slightly different cutoffs.

• In everyday conversation and on pregnancy forums, people often say they are “out of the first trimester” somewhere between 12 and 14 weeks.

Why There’s Confusion

• Different medical bodies and resources use slightly different week ranges for each trimester, which creates overlapping definitions (for example, first trimester ending at week 12 vs. 13+6).

• Many hospital and maternity sites simply round it and say first trimester is 0–13 weeks, second is 14–26, and third is 27–40.

What This Means For You

• If your provider says “once you hit 13 weeks, you’re in the second trimester,” that aligns with common medical and hospital guidance.

• If you are tracking symptoms (like nausea that often eases in early second trimester), many people notice a shift somewhere between weeks 11 and 15, even though the official trimester line is 12–13+ weeks.

A practical rule of thumb: you can safely think of your first trimester as ending around the end of week 12, and by 13 weeks most people will say you have entered the second trimester.

Information gathered from public forums or data available on the internet and portrayed here.