Intra Uterine Devices (IUDs): Types and How They Work
Biology · Reproductive Health · NEET
An Intra Uterine Device (IUD) is a small device inserted into the uterus by a doctor or a trained nurse to prevent pregnancy. There are 3 types: non-medicated (Lippes loop), copper-releasing (CuT, Cu7, Multiload 375) and hormone-releasing (Progestasert, LNG-20). Memory hook: "IUDs work INSIDE the uterus" — they mainly increase phagocytosis (eating) of sperms in the uterus, so fewer sperms survive to fertilise the egg.
The three NCERT types of IUDs and their action. All IUDs increase phagocytosis of sperms in the uterus; copper IUDs add copper-ion action on sperms, and hormone IUDs add implantation and cervical effects. Always inserted by a doctor or expert nurse.
Your doubts, answered
Is an IUD the same as an oral contraceptive pill?
No. An IUD is a physical device placed inside the uterus, while a pill is a hormone taken by mouth. IUDs act locally in the uterus (mainly by increasing phagocytosis of sperms); pills act through hormones that mainly prevent ovulation. NEET often mixes these in matching questions, so keep them separate.
Who inserts an IUD? Can the woman insert it herself?
No, the woman does not insert it herself. IUDs are inserted into the uterus by doctors or expert nurses. This is a common NCERT-based trap: any option saying 'IUDs are generally inserted by the user herself' is WRONG.
What are the 3 types of IUD given in NCERT?
NCERT groups IUDs into three: (1) non-medicated IUDs, example Lippes loop; (2) copper-releasing IUDs, examples CuT, Cu7, Multiload 375; and (3) hormone-releasing IUDs, examples Progestasert and LNG-20. Learn one example for each — NEET repeatedly asks matching questions on these.
Do IUDs stop ovulation or spermatogenesis?
No. IUDs do NOT suppress ovulation, gametogenesis or spermatogenesis. They act inside the uterus by increasing phagocytosis of sperms. Copper ions additionally suppress sperm motility and the fertilising capacity of sperms, and hormone-releasing IUDs also make the uterus unsuitable for implantation and the cervix hostile to sperms.
Is CuT a copper IUD or a hormone-releasing IUD?
CuT (and Cu7, Multiload 375) is a copper-releasing IUD. The Cu (copper) ions it releases suppress sperm motility and the fertilising capacity of sperms. Only Progestasert and LNG-20 are hormone-releasing IUDs — 'LNG' stands for levonorgestrel, a hormone.
Why is IUD a good contraceptive choice for spacing children?
IUDs are ideal for women who want to delay or space their children because they are effective, reversible (fertility returns after removal) and need little day-to-day effort. This is why NCERT calls IUDs one of the most widely accepted methods of contraception in India.
⚠️ The NEET trap ✗ IUDs prevent pregnancy by stopping ovulation, and the woman inserts them herself. ✓ IUDs do NOT stop ovulation. They act inside the uterus by increasing phagocytosis of sperms (copper ions also lower sperm motility/fertilising capacity; hormone IUDs also block implantation). They are inserted by a doctor or expert nurse, not the user. 🧠 IUD = works INSIDE the uterus on sperms, inserted by an expert — it never touches ovulation.
Real NEET questions
NEET 2021
Which one of the following is an example of Hormone releasing IUD?
A · Cu 7
B · Multiload 375
C · CuT
D · LNG 20 ✓
Solution: The hormone-releasing IUDs are Progestasert and LNG-20 (LNG = levonorgestrel, a hormone). Cu7, CuT and Multiload 375 are copper-releasing IUDs, so they are wrong.
NEET 2017
The function of copper ions in copper releasing IUDs is:
A · They suppress sperm motility and fertilising capacity of sperms ✓
B · They inhibit gametogenesis
C · They make uterus unsuitable for implantation
D · They inhibit ovulation
Solution: Copper ions from copper-releasing IUDs (CuT, Cu7, Multiload 375) suppress sperm motility and the fertilising capacity of sperms. Making the uterus unsuitable for implantation is the extra action of hormone-releasing IUDs, and IUDs do not inhibit gametogenesis or ovulation.
NEET 2022
Lippes loop is a type of contraceptive used as:
A · Cervical barrier
B · Vault barrier
C · Non-Medicated IUD ✓
D · Copper releasing IUD
Solution: NCERT names Lippes loop as the example of a non-medicated IUD. Copper-releasing IUDs are CuT, Cu7 and Multiload 375, while caps and vaults are barrier methods, not IUDs.
Solved Reproductive Health NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
An IUD (Intra Uterine Device) is a small device that a doctor or trained nurse places inside the uterus to prevent pregnancy. It works mainly by increasing phagocytosis (destruction) of sperms in the uterus.
They release copper (Cu) ions that suppress sperm motility and the fertilising capacity of sperms, in addition to the usual IUD action of increasing phagocytosis of sperms.
How do hormone-releasing IUDs work?
Along with the usual IUD action, they make the uterus unsuitable for implantation and make the cervix hostile to sperms. Examples are Progestasert and LNG-20.
Do IUDs cause abortion?
No. IUDs are contraceptives — they prevent fertilisation and implantation. They are not abortion methods; ending an established pregnancy is done by MTP, a separate topic.
Are IUDs reversible?
Yes. IUDs are removable and reversible; normal fertility returns after the device is taken out, which is why they suit couples who want to delay or space children.
