Which of the following is not a natural method of contraception?

Options

A. Coitus interruptus
B. Periodic abstinance
C. Lactational amenorrhoea
D. Physical barriers

Answer

To determine which of the following options is not a natural method of contraception, we will analyze each option provided:

1. **Coitus Interruptus**: This method, also known as the withdrawal method, involves the male partner withdrawing his penis from the female's vagina before ejaculation. This method relies on self-control and timing to prevent sperm from entering the female reproductive tract. Since it does not involve any artificial devices or medical interventions, it is considered a natural method of contraception.

2. **Periodic Abstinence**: This method involves avoiding sexual intercourse during the woman's ovulation period when she is most fertile. Couples track the menstrual cycle to identify fertile days and abstain from intercourse during that time. This method also does not involve any artificial means and is therefore classified as a natural method of contraception.

3. **Lactational Amenorrhea**: This method is based on the natural infertility that occurs during the breastfeeding period after childbirth. It is effective as long as the mother is exclusively breastfeeding and has not resumed her menstrual cycle. Since it relies on natural biological processes, it is considered a natural method of contraception.

4. **Physical Barriers**: This method includes the use of condoms, diaphragms, and cervical caps to physically block sperm from entering the uterus. These devices are artificial and are designed to prevent pregnancy through physical obstruction. As such, this method is not considered natural.

Based on the analysis of the options, the answer to the question "Which of the following is not a natural method of contraception?" is **Physical Barriers**.

### Step-by-Step Solution:
1. Identify the methods listed in the options.
2. Analyze each method to determine if it is natural or artificial.
3. Coitus Interruptus: Natural method.
4. Periodic Abstinence: Natural method.
5. Lactational Amenorrhea: Natural method.
6. Physical Barriers: Artificial method.
7. Conclude that Physical Barriers is the method that is not natural.