What is a "trimester"?

What is a "trimester"?

Jay Goldberg (Obstetrician/Gynecologist, Cedars-Sinai Medical Center) gives expert video advice on: What are the risks of being pregnant over 35? and more...

Pregnancy is 40 weeks. From the date of conception to delivery, is typically, on average, 40 weeks. It's broken into trimesters (about 13, 13 1/2 weeks) because certain testing is provided in each trimester. It's like milestones. You get through the first trimester; it's considered a good milestone. You get through the second trimester, it's a better milestone to achieve and then hitting into the third trimester running is a good sign.