During which trimester is the risk of miscarriage at its highest?

The risk of miscarriage is highest during the first trimester of pregnancy, typically defined as the first 12 weeks. This period is critical because it is the time when the embryo is most vulnerable to genetic abnormalities and other factors that can disrupt normal development. The majority of miscarriages that occur during pregnancy happen in this early phase, often due to chromosomal abnormalities, hormonal changes, or problems with implantation.

During the second and third trimesters, while there are still risks of complications, the rates of miscarriage are significantly lower compared to the first trimester. By the second trimester, the embryo has developed further, and the body has adapted to the pregnancy. As the pregnancy progresses into the third trimester, the risks shift more towards factors such as preterm labor or placental issues rather than miscarriage.

Given this information, it is clear why the first trimester is identified as the time of highest risk for miscarriage.