**Question:** Not a barrier contraceptive:

A. Condoms
B. Diaphragm
C. Coitus interruptus
D. Oral contraceptives

**Correct Answer:** C. Coitus interruptus

**Core Concept:** Contraceptive methods primarily aim to prevent pregnancy by interrupting the sexual act (coitus interruptus) or by physical barriers that prevent sperm from reaching the egg (condoms, diaphragms, and intrauterine devices (IUDs)). Oral contraceptives primarily suppress ovulation and do not rely on physical barriers.

**Why the Correct Answer is Right:** Coitus interruptus, also known as withdrawal method, is a traditional form of contraception where a partner withdraws from the vagina just before ejaculation to prevent sperm from reaching the egg. This method is not reliable and has a high failure rate due to the possibility of sperm being present in the vagina or on the penis during withdrawal.

**Why Each Wrong Option is Incorrect:**

A. Condoms: Condoms are a widely used and effective barrier contraceptive method, protecting against sexually transmitted infections and unintended pregnancies.

B. Diaphragms: Diaphragms are another effective barrier contraceptive method, along with spermicide, which helps reduce the number of viable sperm.

D. Oral contraceptives: Oral contraceptives, also known as hormonal contraceptives, work by suppressing ovulation, while also thickening the cervical mucus to make it more hostile to sperm. They do not rely on physical barriers.

**Clinical Pearl:** While oral contraceptives are essential in preventing unintended pregnancies and reducing the risk of certain cancers, they are not considered a barrier contraceptive method. Using barrier contraceptives like condoms or diaphragms in combination with hormonal contraceptives can improve overall contraceptive effectiveness.