Question

The method of "Periodic Abstinence" is based on which physiological fact?

• A. Ovum remains viable for about 1-2 days.
• B. Sperm survive for about 3 days.
• C. Ovulation occurs around the 14th day of the cycle.
• D. All of the above facts combined.

Hint:

The fertile period during which couples should abstain from coitus is typically considered to be from day 10 to day 17 of the menstrual cycle, when the chances of fertilization are extremely high.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Periodic abstinence is a natural method of contraception (also known as the rhythm method or fertility awareness-based method).
It involves tracking the menstrual cycle and avoiding sexual intercourse during the "fertile window"—the specific days in the cycle when fertilization is most likely to occur.
The success of this method depends entirely on a precise understanding of reproductive physiology and timing.
Step 2: Detailed Explanation:
The "fertile window" is calculated based on three intersecting biological facts:
1. Timing of Ovulation: In a standard \( 28 \)-day cycle, ovulation (the release of the egg) usually occurs around day \( 14 \). Because cycles can vary, scientists consider days \( 10 \) to \( 17 \) as the high-risk fertile period.
2. Viability of the Ovum: Once the egg is released from the follicle, it only lives for about \( 24 \text{--} 48 \) hours (approximately \( 1 \text{--} 2 \) days). If it is not fertilized within this short time frame, it begins to disintegrate.
3. Longevity of Sperm: Sperm deposited in the female reproductive tract can survive and remain capable of fertilizing an egg for up to \( 72 \) hours (about \( 3 \) days).
Synthesis:
Because sperm can wait for \( 3 \) days for an egg, and an egg can survive for \( 2 \) days waiting for sperm, the danger zone for pregnancy starts several days before ovulation and ends a couple of days after. Without any one of these three facts, the method would not be logically sound. Therefore, the method is built upon the synthesis of all these physiological parameters.
Step 3: Final Answer:
The basis for periodic abstinence is the combination of sperm survival, ovum viability, and the predictable timing of ovulation. Option (D) is correct.