Introduction
This note covers abortion and ectopic pregnancy: their definitions, causes, the characteristic microscopic structures, possible sites and the complications.
Abortion
Abortion is defined as termination of pregnancy before the 28th week of gestation. It is classified as spontaneous or induced.
- In the 1st trimester spontaneous abortion is due to fetal or maternal causes.
- Induced abortion is therapeutic, legal or illegal.
Causes of spontaneous abortion
- Fetal: chromosomal abnormalities (the most common cause in the first trimester) and developmental defects of the embryo.
- Maternal: endocrine disorders (luteal phase defect, diabetes, thyroid disease), infections, uterine anomalies and fibroids, cervical incompetence, autoimmune disease, trauma and toxins.
Pathognomonic microscopic structures in abortion
- Focal areas of decidual necrosis with intense neutrophilic infiltration.
- Thrombi within decidual blood vessels.
- Increased amount of haemorrhage with necrotic decidua.
- Placental villi may be oedematous and lack blood vessels.
Complications
- Haemorrhage and anaemia; retained products of conception.
- Infection: septic abortion, which can lead to endometritis, pelvic inflammatory disease, sepsis and septic shock (especially after illegal abortion).
- Disseminated intravascular coagulation and, later, infertility from uterine scarring.