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Question #45579
The Question
In a demographic study, a paradoxical increase in Infant Mortality Rate (IMR) was linked to reduced birth spacing, despite mothers relying on Lactational Amenorrhea (LAM) as a natural contraceptive. Many of these mothers conceived before the return of their first postpartum menses. Which of the following physiological events best explains this contraceptive failure?
Options
- A.
A slight decrease in suckling intensity reduces prolactin levels, allowing GnRH pulsatility to resume and trigger an LH surge, causing ovulation prior to the first postpartum menses.
- B.
Continuous breastfeeding maintains high oxytocin levels, which eventually downregulates GnRH receptors in the anterior pituitary, leading to spontaneous ovulation.
- C.
High prolactin levels successfully inhibit FSH secretion but fail to suppress the basal secretion of LH, allowing a dominant follicle to rupture without prior menstruation.
- D.
The method remains highly effective for up to one year postpartum, but fails because high prolactin directly stimulates the ovaries to undergo silent ovulation.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Reproductive_Health|Spermatogenesis_vs_Oogenesis_Chronology|Lactational_Amenorrhea
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that as long as amenorrhea (absence of menses) persists, ovulation cannot occur.
The pivot is understanding the sequence of the menstrual cycle: ovulation precedes menstruation.
If the prolactin threshold drops, ovulation happens first, leading to pregnancy before the mother ever sees a warning sign (menses).
It also tests the functional distinction between Prolactin and Oxytocin, and the strict NCERT timeline of 6 months for LAM efficacy.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Reproductive Health - Class 12 |
| Concept | Public Health Indicators |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |