While the definitions of pregnancy loss, miscarriage, and recurrent pregnancy loss vary across national and international organizations, the American Society for Reproductive Medicine (ASRM) uses the definitions below:
- Pregnancy loss is the death of a fetus before birth, regardless of the duration of the pregnancy. A pregnancy loss can include induced terminations, also known as abortions. Pregnancy loss during the first trimester (less than 10 weeks gestation) occurs in approximately 1 in 7 known pregnancies.
- Clinically recognized miscarriages, defined as an early pregnancy loss, are common, occurring in approximately 15–25% of pregnancies. Miscarriages can occur for many different reasons.
- Recurrent pregnancy loss (RPL) is defined by two or more failed clinical pregnancies. Up to 50% of cases of RPL will not have a clearly defined cause.
The terms of fetal death and stillbirth are often used interchangeably. The Center for Disease Control and Prevention (CDC) uses the definitions below:
- A fetal death is the death of a fetus before birth, regardless of the duration of the pregnancy. Fetal deaths do not include abortions.
- A stillbirth is the death of a fetus after 20-week gestation and before birth.