If you are a new mother to be, you might be a bit confused as to when does third trimester start. One thing you have to understand is that each trimester is a grouping of three months. Since you are usually pregnant for about nine months, then there are going to be three trimesters during your pregnancy. The third trimester gives you a 90 percent plus chance of survival for the baby if you go into labor for any reason. This includes forced labor if there are medical complications involved. The baby has a greater than 90 percent chance to survive even if medical attention is required.
There is, however, some confusion as to exactly when does third trimester start. Some people will tell you that the third trimester starts at the 29th or 30th week where others are going to tell you that it will start around the 25th week of your pregnancy. The reason is that there are two gestational periods that people will go by. You are only pregnant for 266 days, but one gestational period is added into this from the time of ovulation, and that adds in the extra two weeks. This, of course, throws the trimester count off just a bit.
A good way to get around this is to change when does third trimester start means to you. Most women are saying that their third trimester starts around week 28. Even if they are a bit later than the 25th week trimester start, they are still within the 90 percent chance of survival period for their baby. That is the most important aspect of counting your trimesters, after all. Your doctor might tell you to wait until the 30th week to declare your third trimester; but unless you know the actual day of ovulation and conception, it’s all estimated anyway.
Women that are actively keeping count of their ovulation and fertility because they are trying to get pregnant will have a better estimation of when does third trimester start. These women will be actively keeping track of everything they are doing around their ovulation cycle and can simply count the weeks out from the time of conception to determine when their third trimester happens. Women that aren’t actively trying to become pregnant and, instead, find it a rather pleasant surprise that they got pregnant, will usually count around 28 weeks as the start, and leave the rest of the estimations up to their doctor from there on out.↑ Back to Top