when does second trimester start

The second trimester of pregnancy starts at around week 13 and lasts through the end of week 27 or 28, depending on the source. It marks the middle part of pregnancy, often referred to as months 4, 5, and 6. This period is typically when early pregnancy symptoms like morning sickness begin to fade, and the fetus continues significant development. Many people start to feel fetal movements between weeks 18 to 20, sometimes earlier. The third trimester then begins at about week 28.