Spontaneous Abortion: Clinical Overview and Classification
Spontaneous abortion, also known as miscarriage, is defined as the noninduced loss of pregnancy before 20 weeks' gestation. In medical terms, pregnancy is the status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. It is important to note that the layperson use of the term “abortion” is often intended to refer to induced termination of a pregnancy, whereas “miscarriage” is preferred for spontaneous loss.
Epidemiology
Spontaneous abortion is a common complication of early pregnancy. It accounts for pregnancy loss in 10%–20% of clinically recognized pregnancies. While it occurs in all age groups, the incidence—which is the number of new cases of a given disease during a given period in a specified population—is higher in women > 35 years of age.
Etiology and Timing
Most spontaneous abortions occur within the 1st 12 weeks of gestation. These events can be caused by several factors such as infection, trauma, and genetic and autoimmune causes.
Classification
Spontaneous abortion can be classified into several types based on clinical presentation. These categories help clinicians determine the appropriate course of action.
| Type of Spontaneous Abortion |
|---|
| Threatened abortion |
| Inevitable abortion |
| Incomplete abortion |
| Complete abortion |
| Missed abortion |
Clinical Presentation and Diagnosis
Spontaneous abortions are diagnosed based on history, physical examination, and ultrasound findings. Differential diagnosis is also a key part of the clinical evaluation process.
Management
Once a diagnosis is established, management options include expectant, medical, or surgical therapy.