Answer the following:
Why is rhythm method not 100 per cent safe?

Explanation

### Step-by-Step Solution:

1. **Definition of the Rhythm Method**: The rhythm method, also known as the calendar method or safe period method, is a natural family planning technique that involves tracking the menstrual cycle to determine the fertile and non-fertile days.

2. **Understanding Ovulation**: Ovulation typically occurs around the middle of the menstrual cycle, approximately 12 to 14 days before the start of the next period. The days leading up to and following ovulation are considered fertile days.

3. **Identifying Safe Periods**: The rhythm method relies on identifying the "safe period," which is calculated by avoiding intercourse during the fertile days (around ovulation) and engaging in it during the non-fertile days.

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