Given below are two statements, one is Assertion (A) and other is Reason (R).

Assertion (A): When the placenta is implanted partially or completely over the lower uterine segment it is called placenta previa.

Reason (R): The fertilized ovum drop down and implants in the lower uterine segment.

Select the correct answer using the code given below:

1. A

   Both (A) and (R) are true and (R) is correct explanation of (A)

2. B

   Both (A) and (R) are true but (R) is not correct explanation of (A)

3. C

   (A) is true but (R) is false

4. D

   (A) is false but (R) is true

Appeared in: UPPSC 2022

Explanation

• Assertion (A) is a factually correct statement that provides the standard medical definition of placenta previa.
• Reason (R) is also a factually correct statement, describing the 'dropping down theory,' which is a widely accepted explanation for the cause of placenta previa.
• The reason directly explains the assertion. The low implantation of the fertilized ovum (the event described in R) is the direct cause of the placenta developing in a low-lying position (the condition described in A).
• Therefore, both statements are true, and R is the correct and logical explanation for A.

Why Other Options Were Wrong

• Option B: This option is incorrect because the reason is not just a separate true statement; it is the direct cause of the assertion. The low implantation of the ovum is the mechanism that leads to placenta previa.
• Option C: This option is incorrect because Reason (R) is a valid and accepted theory for the development of placenta previa. The 'dropping down theory' is a key concept in understanding its etiology.
• Option D: This option is incorrect because Assertion (A) provides the correct and standard definition of placenta previa. It is a true statement.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology and definition of Placenta Previa as background academic context rather than a clinical decision trigger.
• The hallmark sign of placenta previa is painless, bright red vaginal bleeding, typically occurring in the second or third trimester. This is a key diagnostic clue for nurses.
• A critical nursing and medical safety protocol is to NEVER perform a digital vaginal examination on a patient with suspected placenta previa, as it can disrupt the placental implantation site and cause catastrophic hemorrhage.
• What if? If the bleeding were painful and the blood was dark red, the priority diagnosis would shift from placenta previa to abruptio placentae. This would require immediate assessment for fetal distress and maternal signs of shock, as it indicates a different, often more acute, emergency.

How to Approach the Question

• First, evaluate Assertion (A) for its factual accuracy. Recall the definition of placenta previa: implantation of the placenta in the lower uterine segment.
• Confirm that statement (A) is a correct definition.
• Next, evaluate Reason (R) for its factual accuracy. Recall the theories about the causes of placenta previa, specifically the 'dropping down theory' of ovum implantation.
• Confirm that statement (R) describes a valid etiological theory.
• Finally, determine the relationship between the two statements. Does the low implantation of the ovum (R) directly cause the placenta to be located in the lower segment (A)?
• Since the location of implantation determines the location of placental development, (R) is the direct explanation for (A).

Concept Tested & Keywords

• Concept Tested: Etiology and definition of Placenta Previa.
• Stem keywords: placenta previa, lower uterine segment, implantation, fertilized ovum, Assertion (A), Reason (R)
• Lead-in keywords: correct explanation
• Negative lead-in flag: false

Question ID

QFV7QND85ohb_pO4DdsYu7

Copy ID

Reference Book

E6 Obstetrics Williams p. 70-94