How to iuds work

Overview

Intrauterine devices, commonly known as IUDs, are a highly effective, long-acting reversible contraception (LARC) method. They are small, T-shaped devices inserted into the uterus by a trained healthcare professional. IUDs are designed to provide continuous pregnancy prevention for several years, making them a convenient and reliable choice for many individuals seeking contraception.

How IUDs Work

The mechanism by which IUDs prevent pregnancy differs slightly between the two main types: hormonal IUDs and copper IUDs.

Hormonal IUDs

Hormonal IUDs release a small amount of progestin, a synthetic version of the hormone progesterone, directly into the uterus. This progestin works in several ways to prevent pregnancy:

• Thickening of Cervical Mucus: The progestin thickens the mucus in the cervix, creating a barrier that makes it difficult for sperm to travel through to reach an egg.
• Thinning of the Uterine Lining: Progestin also thins the endometrium, the lining of the uterus. This makes it less likely for a fertilized egg to implant, even if fertilization were to occur.
• Inhibition of Ovulation (less common): In some cases, particularly with higher doses of progestin, hormonal IUDs can suppress ovulation, meaning the ovaries do not release an egg. However, this is not the primary mechanism of action for most hormonal IUDs.

Hormonal IUDs are available in different strengths and can last for varying periods, typically 3 to 8 years, depending on the brand.

Copper IUDs

Copper IUDs do not contain hormones. Instead, they have copper wire coiled around the stem and arms of the T-shaped plastic frame. The copper acts as a spermicide, creating an inflammatory reaction within the uterus that is toxic to sperm. This toxicity:

• Impedes Sperm Motility: The copper ions make it difficult for sperm to move effectively, reducing their ability to reach and fertilize an egg.
• Prevents Fertilization: The inflammatory response and the presence of copper ions can prevent sperm from fertilizing an egg.
• Alters Uterine Environment: The copper also changes the uterine environment, making it less hospitable for implantation.

Copper IUDs are typically effective for up to 10 years and are a non-hormonal option for contraception.

Insertion and Removal

The insertion of an IUD is a procedure performed by a healthcare provider. It involves using a speculum to visualize the cervix, similar to a Pap smear. The IUD is then loaded into an applicator and guided through the cervix into the uterus. Most people experience some cramping during and after insertion, which usually subsides within a few days. Some IUDs have strings attached that hang through the cervix into the vagina, which can be used by the individual or the provider to check placement and to aid in removal.

Removal is also a simple procedure done by a healthcare provider. They gently pull on the strings to dislodge the IUD from the uterine wall. For hormonal IUDs, removal typically results in the return of fertility within a few weeks.

Effectiveness and Safety

IUDs are among the most effective forms of birth control available, with failure rates typically less than 1% when used correctly. They are considered safe for most people, including adolescents and those who have not given birth. However, as with any medical procedure, there are potential risks and side effects, such as irregular bleeding, cramping, and, in rare cases, expulsion of the IUD or uterine perforation during insertion. It is important to discuss your medical history and any concerns with your healthcare provider to determine if an IUD is the right choice for you.