When does miscarriage usually happen in a pregnancy?

The most common period one experiences a miscarriage is before the 12th week of pregnancy, within the first trimester. There is a 31% chance of women experiencing a miscarriage within the first six weeks of pregnancy. A miscarriage between the first 6 to 7 weeks of pregnancy might occur if the gestational sac is empty or if the fetus does not have heart activity. Once the fetal heart rate is present after the first six weeks of pregnancy, there is less chance of experiencing a miscarriage. Statistics show a 1 to 5% chance of a miscarriage occurring within the second trimester, between the 13th and 19th week of pregnancy.