**Question:** Mechanism of action of IUCD is A/E -

A. Inhibition of ovulation
B. Progestin release
C. Endometrial irritation
D. Antibacterial effect

**Core Concept:** Intrauterine Contraceptive Devices (IUCDs) are long-acting reversible contraceptives that act through various mechanisms.

**Why the Correct Answer is Right:** The correct answer, A/E - Inhibition of ovulation, explains the primary mechanism by which IUCDs prevent pregnancy. Intrauterine devices work by releasing copper ions or progestogens (e.g., levonorgestrel) into the uterine cavity. This leads to:

1. **Inhibition of ovulation (A):** The copper ions and progestogens interfere with the process of ovulation. They cause inflammation and irritation of the fallopian tubes, making them less hospitable for sperm and ovum. Additionally, progestogens can inhibit the maturation and release of the ovum.

2. **Endometrial irritation (E):** IUCDs cause a mild inflammatory response in the uterine lining (endometrium). This can lead to a reduction in the receptivity of the endometrium for implantation, thereby decreasing the chances of successful fertilization and implantation.

**Why Each Wrong Option is Incorrect:**

3. **Progestin release (B):** While IUCDs do release progestogens, the primary mechanism is not solely progestin release but the combination of ovulation inhibition and endometrial irritation.

4. **Antibacterial effect (D):** Although IUCDs have a mild antimicrobial effect, it is not the primary mechanism for contraception. The main focus should be on ovulation inhibition and endometrial irritation.

**Clinical Pearl:** IUCDs are a reliable and reversible method of contraception, offering protection against unintended pregnancies for up to 10-15 years. They have also been shown to reduce the risk of pelvic infections and provide mild pain relief during menstruation.

However, IUCDs have some potential side effects, such as menstrual irregularities, pelvic pain, and rare complications like ectopic pregnancy, expulsion, and uterine perforation. These devices should be discussed during family planning counseling to help patients make an informed decision about contraceptive methods.