A miscarriage that occurs before week 12 is the most common and often due to a genetic or chromosomal abnormality in the foetus. Read more in the article Early Miscarriage.
This is defined as a miscarriage that occurs after week 12 up to week 22. After week 22, it is no longer considered a miscarriage but is referred to as intrauterine foetal death. The cause is not always clear, but it may be due to an infection or weakness in the cervix (the neck of the uterus).
A missed abortion, also known as a retained miscarriage means that the miscarriage is delayed, and it takes time, sometimes several weeks, before the body expels the foetus. This is noticed by the onset of bleeding, or it may be discovered during an ultrasound examination. Often, pregnancy symptoms persist even though the foetus is no longer alive.
The definition of recurrent miscarriage usually means that you have had three or more consecutive miscarriages. The recommendation here is to contact your healthcare provider so that you can undergo an investigation to try to find the reason for the miscarriages.