Skip to content
Question

Q.Assertion (A) : Cu-T, Cu-7 and LNG-20 are the most widely used copper-releasing IUDs. Reason (R) : Cu-ions in IUDs effectively suppress sperm motility and the fertilising capacity of sperms.

CBSECBSE Class XII Board 2025MCQ· 1mImportance★★★★★
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Copper-releasing IUDs work by releasing Cu²⁺ ions that impair sperm function and prevent fertilisation; both the assertion about widely used IUDs and the reason explaining their mechanism are correct and linked.

The question tests your understanding of intrauterine devices (IUDs) as a contraceptive method, specifically the mechanism by which copper-releasing IUDs prevent pregnancy. This is a classic assertion-reason question where you need to evaluate two statements: whether each is true, and whether the reason correctly explains the assertion.

Let's first understand what makes copper IUDs effective. When a copper-releasing IUD is placed in the uterus, it continuously releases cupric ions (Cu²⁺) into the uterine and tubal fluids. These ions create a hostile environment for sperm in multiple ways: they damage sperm membranes, reduce sperm motility (movement), and critically impair the sperm's ability to undergo capacitation and the acrosome reaction—both essential for fertilisation. The copper ions also trigger a local inflammatory response that further enhances the contraceptive effect. Importantly, this is primarily a spermicidal mechanism, not an abortifacient one; fertilisation itself is prevented.

Now let's evaluate each statement:

Evaluating Assertion (A):

  1. Cu-T is indeed one of the most common copper IUDs, shaped like the letter T with copper wire wound around the stem.

  2. Cu-7 (also called Copper-7) was historically significant and widely used, though it has been largely replaced by newer models in many countries. It had a "7" shape.

  3. LNG-20 refers to the levonorgestrel-releasing intrauterine system (Mirena being a brand name), which releases 20 μg of the hormone levonorgestrel per day. Here's the critical point: LNG-20 is not a copper-releasing IUD—it's a hormonal IUD.

The assertion mixes copper IUDs (Cu-T, Cu-7) with a hormonal IUD (LNG-20). While all three are IUDs, only the first two release copper. More accurate examples of copper IUDs would be Cu-T 380A, Cu-375, or Multiload 375.

Watch out

A common confusion: not all IUDs work the same way. Copper IUDs release Cu²⁺ ions, while hormonal IUDs like LNG-20 release progestogen. They have different mechanisms of action.

Evaluating Reason (R):

The reason states that Cu-ions suppress sperm motility and fertilising capacity. This is absolutely correct. The mechanism includes:

  • Direct toxic effect on sperm
  • Inhibition of sperm motility
  • Interference with sperm metabolism
  • Prevention of sperm capacitation
  • Alteration of cervical mucus
  • Changes in the endometrium that prevent implantation (secondary mechanism) …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.