Definition - What does Trimester mean?
A trimester is a stage of pregnancy lasting three months.
FertilitySmarts explains Trimester
Pregnancy lasts roughly nine months (or 40 gestational weeks) and is divided into three trimesters:
- First trimester - first three months (1-12 gestational weeks)
- Second trimester - middle three months (12-28 gestational weeks)
- Third trimester - last three months (28-40 gestational weeks)