Spontaneous abortion or miscarriage is defined as the loss of pregnancy less than 20 weeks gestation. The American College of Obstetricians and Gynecologists (ACOG) estimates it is the most common form of pregnancy loss. It is estimated that as many as 26% of all pregnancies end in miscarriage and up to 10% of clinically recognized pregnancies. Moreover, 80% of early pregnancy loss occurs in the first trimester. The risk of miscarriage decreases after 12 weeks gestation. Most clinically apparent miscarriages (two-thirds to three-quarters in various studies) occur during the first trimester. About 30% to 40% of all fertilized eggs miscarry, often before the pregnancy is known. uterine Early miscarriages can be due to a developmental abnormality of the placenta or other embryonic tissues. In some instances an embryo does not form but other tissues do. This has been called a "blighted ovum".Treatment options include expectant management, medication, or surgical interventions. Decisions are often made jointly with the patient and the obstetrician as to which path to choose. As long as patients are hemodynamically stable and do not require emergency surgery, there is no difference in long-term outcomes when comparing these treatment options. Expectant management is typically limited to those miscarrying in the first trimester due to lack of studies beyond that timeframe and presumed increased risk of bleeding complications beyond that. Approximately 80% of women achieve complete passage of intrauterine contents within 8 weeks.