The copper component of the ParaGard intrauterine device functions primarily to:

• A. Thicken the endometrium and cervical mucus
• B. Decrease the movement of ovum through the fallopian tubes
• C. Interfere with estrogen uptake and decrease sperm motility
• D. Suppress ovulation

Answer: (C)

The copper component of the ParaGard intrauterine device primarily functions to create an inflammatory reaction in the uterine environment, which is toxic to sperm and ova. This action hinders sperm motility, making it difficult for sperm to reach and fertilize an ovum. The presence of copper does not directly interfere with estrogen uptake or have a significant impact on hormonal mechanisms but rather works through a non-hormonal mechanism that disrupts the normal functioning of sperm.

Although some mechanisms like thickening the cervical mucus or affecting ovum transit could play a role in the overall contraceptive efficacy of various forms of birth control, the specific action of the copper in the ParaGard is most closely associated with its role in impeding sperm motility. This inflammatory response, rather than hormonal suppression or modification, is a key aspect of how copper IUDs prevent pregnancy effectively.