My doctor said 2nd tri starts at 12 weeks 1 day.
The pregnology ticker says it starts at 13weeks.
A few internet sights say it starts at 13weeks 1 day.
Other internet sights say it starts at 14 weeks.
So sometime between Monday and November 8th, I'll be in 2nd tri!! haha
Re: S/O- 2nd Tri?
I saw it worked out the other day if you divide 40 weeks into 3 it is 2nd tri begins @ 13w3days,3rd tri begins @ 26w6d. Hope that helps.
Edit...p-brain error.
This. The reasoning behind the 12 weeks is technically 37 weeks is full term, so 37 divide by 3 is 12w3d.
I found this to be helpful last time around:
The three basic ways to calculate trimesters
Development, Gestation, Conception. They give different dates for when the second trimester begins and for when the third trimester begins. Your health care provider might prefer to use the Development method, while another Midwife or Doctor may use the Gestation method.
I am sure they do that just to confuse pregnant women.
by Development:
This uses actual developmental stages to divide up a pregnancy. From LMP to 12 weeks the embryo develops all the major organs and becomes a fetus. From 12 weeks to 27 weeks the fetus continues developing and reaches viability. From 27 weeks on the fetus finishes development and prepares for delivery. Here the second trimester begins at 12w 0d and the third at 27w 0d.by Gestation:
With this method you take the 40 weeks of gestation and divide by three. Here the second trimester begins at 13w 3d and the third at 26w 6d.by Conception:
This method is where you take the 38 weeks of post conception development, divide by three, and add two weeks. Here the second trimester begins at 14w 5d and the third at 27w 3d.that is very interesting!