Which of the following factor induces the lactational amenorrhoea ?

Options

A. Increased level of estrogen
B. Decreased level of oxytocin
C. Increased level of prolactin
D. Increased level of progesterone

Answer

### Step-by-Step Solution:

1. **Understanding Lactational Amenorrhea**:
- Lactational amenorrhea is a natural form of contraception that occurs during the first six months postpartum when a woman is breastfeeding. During this period, menstruation is absent, and the chances of ovulation and pregnancy are significantly reduced.

2. **Physiological Mechanism**:
- The absence of menstruation and ovulation during lactation is primarily due to hormonal changes in the body. Specifically, the levels of certain hormones fluctuate to prevent ovulation.

3. **Hormonal Factors**:
- **Estrogen**: Typically, high levels of estrogen promote ovulation. However, during breastfeeding, estrogen levels are lower.
- **Prolactin**: This hormone is crucial for milk production. During breastfeeding, prolactin levels are elevated, which inhibits the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus.
- **Gonadotropin-Releasing Hormone (GnRH)**: This hormone is responsible for stimulating the release of other hormones (LH and FSH) that are necessary for ovulation.
- **Oxytocin**: This hormone helps with milk ejection during breastfeeding but does not directly influence ovulation.

4. **Conclusion**:
- The key factor that induces lactational amenorrhea is the **increased level of prolactin**. Elevated prolactin levels inhibit GnRH, which in turn prevents the secretion of hormones necessary for ovulation, thus leading to amenorrhea.

5. **Final Answer**:
- The correct answer to the question is **increased level of prolactin**.