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Question #45356
The Question
A nursing mother relying on the Lactational Amenorrhea Method (LAM) for contraception conceives at 5 months postpartum, despite having experienced no menstrual bleeding since delivery. Which of the following statements correctly identifies the physiological mechanism of lactational amenorrhea and the primary reason for its failure in this scenario?
Options
- A.
High oxytocin exerts negative feedback on the anterior pituitary to suppress FSH; failure occurs because oxytocin levels fluctuate independently of suckling intensity.
- B.
High prolactin suppresses pulsatile GnRH release, preventing the LH surge; failure occurs because the first postpartum ovulation precedes the first postpartum menstruation.
- C.
Prolactin directly inhibits the proliferation of the endometrial lining; failure occurs because ovarian follicular development and ovulation continue uninterrupted.
- D.
High prolactin maintains the corpus luteum to secrete progesterone continuously; failure occurs when the corpus luteum abruptly degenerates after 4 months.
Check Your Answer
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
Hypothalamus|GnRH|Prolactin|FSH|LH
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line 'absence of menstruation means chances of conception are almost nil' without understanding the chronological sequence of the reactivated HPG axis.
The trap is failing to realize that ovulation (the release of the ovum) must chronologically precede menstruation (the shedding of the unfertilized ovum's endometrial bed).
Therefore, a woman becomes fertile before her first warning sign (menses) appears.
Additionally, it tests the classic functional confusion between Prolactin (milk synthesis and GnRH suppression) and Oxytocin (milk let-down).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Hormonal Feedback Loops |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |