Spontaneous Abortion Overview

What is the most common genetic abnormality associated with first trimester abortions?

At what gestational age is fetal viability typically recognized in the USA?

Which of the following is considered a uterine factor that can contribute to spontaneous abortions?

What percentage of all pregnancies typically experience spontaneous abortion?

Which factor is NOT associated with an increased incidence of spontaneous abortion in multiple pregnancies?

Spontaneous Abortion

Definition of Abortion: The loss (termination) of pregnancy before the age of fetal viability.
Definition of Fetal Viability: The gestational age at which a fetus has a reasonable chance to live outside the uterus with assistance.
- 24 weeks in Egypt and the UK
- 20 weeks or 500 grams in the USA
Incidence: Approximately 20% of all pregnancies.
- Exact incidence is difficult to estimate because some first-trimester abortions are undetected (subclinical).
- Criminal abortions are not typically recorded.

Causes of Spontaneous Abortion

Fetal Causes:
- Genetic Abnormalities: The most common cause of first-trimester abortions, particularly associated with advanced maternal age.
  - Examples include aneuploidy (e.g., trisomy 16, 18, 21; monosomy X).
- Congenital Malformations: These can occur in conjunction with genetic abnormalities. Exposure to teratogens (agents that cause birth defects) can also affect development.
- Multiple Pregnancies: These have a higher incidence of abortion.
Parental Causes:
- Genetic Abnormalities: For example, balanced translocations.
- Uterine Factors:
  - Congenital anomalies (e.g., uterine septum).
  - Cervical incompetence: A common cause in the second trimester.

This quiz covers the essentials of spontaneous abortion, including definitions, incidence, and causes. It highlights fetal viability and discusses various fetal causes such as genetic abnormalities and congenital malformations. Understanding these concepts is crucial for comprehending reproductive health.