## **Core Concept**
The concept of stillbirth is crucial in obstetrics and is defined by specific gestational age and fetal weight criteria. Stillbirth, also known as fetal demise or intrauterine fetal death, refers to the birth of a baby who has died in the womb after a specified gestational period. The definition can vary slightly by jurisdiction but generally involves a gestational age threshold.

## **Why the Correct Answer is Right**
The correct answer, **22 weeks**, is significant because it represents a commonly accepted gestational age threshold for defining stillbirth. Before this period, the loss is typically considered a miscarriage. The World Health Organization (WHO) defines stillbirth as babies born dead at 28 weeks of gestation or more. However, different countries and medical organizations may use slightly different criteria, often around 20-28 weeks. A commonly used threshold in many contexts for the definition of stillbirth is **22 weeks** of gestation or a fetal weight of 500 grams.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Less than 20 weeks is generally considered a period for miscarriage, not stillbirth.
- **Option B:** 28 weeks is indeed a criterion used by WHO and some countries for stillbirth, but the question seems to seek a more universally applicable early gestational age threshold.
- **Option D:** More than 30 weeks is beyond the typical threshold for defining stillbirth and leans more towards term gestation.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that stillbirth definitions can vary by country and organization. For example, the American College of Obstetricians and Gynecologists (ACOG) and the WHO have slightly different criteria, but **22 weeks** is a commonly cited threshold in many contexts. Understanding these definitions is crucial for clinical practice, research, and statistics.

## **Correct Answer:** B. 22 weeks.