## **Core Concept**
Prolonged pregnancy, also known as post-term pregnancy, refers to a pregnancy that extends beyond the normal gestational period. The normal gestational period is typically considered to be between 37 weeks and 42 weeks of gestation.

## **Why the Correct Answer is Right**
The correct definition of prolonged pregnancy is a gestation period that exceeds 42 weeks. This is because the risk of complications for both the mother and the fetus increases significantly after 42 weeks. The World Health Organization (WHO) and other medical guidelines define prolonged pregnancy as pregnancies that have reached or surpassed 42 weeks of gestation.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because a pregnancy lasting less than 37 weeks is considered preterm, not prolonged.
* **Option B:** This option suggests 40 weeks, which is within the normal range for gestation and not considered prolonged.
* **Option C:** While 41 weeks is sometimes considered late-term, it is not the threshold for defining a prolonged pregnancy.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that pregnancies that go beyond 42 weeks are associated with increased risks such as fetal distress, meconium aspiration syndrome, and decreased fetal movement. Monitoring and possible intervention are crucial in such cases.

## **Correct Answer:** D. 42 weeks.