What is the primary function of an intrauterine device (IUD)?

An intrauterine device (IUD) serves multiple functions in contraceptive management, which is why the option that encompasses all these functions is the correct choice.

IUDs primarily prevent pregnancy through several mechanisms. Firstly, they can prevent ovulation in some users, particularly with hormonal IUDs, which release levonorgestrel. This hormone can stop the ovaries from releasing eggs, thereby reducing the chance of fertilization.

Additionally, IUDs create a physical barrier to sperm by interfering with sperm movement within the uterus and fallopian tubes. Hormonal IUDs also thicken cervical mucus, which makes it difficult for sperm to travel through the cervical canal and reach an egg.

The combined actions of preventing ovulation, thickening cervical mucus, and inhibiting sperm movement provide a comprehensive approach to contraception, making the option that states "all of the above" the most accurate answer. Each mechanism contributes to the overall efficacy of IUDs in preventing pregnancy.