In adult womenK____ may cause menstrual cycle to become irregular

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which condition in adult women may lead to irregular menstrual cycles.

2. **Identifying Relevant Hormones**: It is important to recognize the role of hormones in regulating the menstrual cycle. Key hormones include estrogen, progesterone, and thyroid hormones.

3. **Role of Thyroid Hormones**: Thyroid hormones are crucial for maintaining the body's metabolic rate and overall hormonal balance. Any disorders related to these hormones can disrupt normal bodily functions.

4. **Effects of Thyroid Disorders**: Thyroid disorders, particularly hypothyroidism, can lead to irregularities in the menstrual cycle. This can manifest as early or late menstruation, or changes in the flow of menstrual periods (light or heavy).

5. **Specific Impact of Hypothyroidism**: In cases of hypothyroidism, women may experience:
- Absence of menstrual cycles (amenorrhea)
- Changes in coagulation factors leading to heavy bleeding
- Increased prolactin levels, which can inhibit ovulation

6. **Conclusion**: Based on the information gathered, hypothyroidism is the condition that may cause menstrual cycles in adult women to become irregular.

**Final Answer**: Hypothyroidism may cause menstrual cycles to become irregular in adult women.

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