Read the following passage and answer any four questions given below:
Lactational amenorrhea, is also called as postpartum infertility. It occurs when a women is not menstruating and fully breast feeding. It is a temporary family planning method. It is a contraceptive method where the mother is informed and supported in how to use breast feeding for contraception. As breast feeding delays the return of a mother's ovulation (when the woman's ovary releases an egg) and may make her infertile for six months or more.
Lactational amenorrhea is due to action of which hormone :

Options

A. Prolactin induced inhibition of GnRH
B. Prolactin induced inhibition of FSH
C. Oxytocin induced inhibition of GnRH
D. Oxytocin induced inhibition of FSH

Explanation

**Step-by-Step Solution:**

1. **Understanding Lactational Amenorrhea**:
- Lactational amenorrhea is a condition that occurs in women who are fully breastfeeding and not menstruating. This condition is often referred to as postpartum infertility.

2. **Mechanism of Action**:
- During breastfeeding, the body produces higher levels of the hormone prolactin. Prolactin is responsible for stimulating milk production in the mammary glands.

3. **Impact on Ovulation**:
- The elevated levels of prolactin have a significant effect on the reproductive hormones. Specifically, prolactin inhibits the release of Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus.

4. **Consequences of GnRH Inhibition**:
- Since GnRH is responsible for stimulating the release of gonadotropins (FSH and LH) from the pituitary gland, its inhibition leads to a decrease in the levels of these hormones.
- FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone) are crucial for the menstrual cycle and ovulation. Their reduced levels result in the absence of menstruation and ovulation.

5. **Conclusion**:
- Therefore, lactational amenorrhea is primarily due to the action of the hormone prolactin, which induces the inhibition of GnRH. This leads to the absence of FSH and LH, preventing ovulation and menstruation.

**Final Answer**: Lactational amenorrhea is due to the action of **prolactin**, which induces the inhibition of GnRH.

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