How Does an IUD Work?

There are many types of birth control on the market that are highly effective in preventing pregnancy. Women who are looking to prevent pregnancy for several years may choose an intrauterine device (IUD) – but which option is best?

At her practice in the Upper East Side of Manhattan, New York, Dr. Inga Zilberstein provides various birth control methods, including the IUD. This month, we cover the pros and cons of IUDs and describe how they work to help you decide on the best choice for your needs.

What is an IUD?

This small device, no larger than a quarter, looks like a “T” and sits inside the uterus to prevent pregnancy. We insert it through the vagina and into the uterus in a simple in-office procedure.

It’s a long-term contraception option that lasts up to 10 years, depending on the type. IUDs are highly effective and come with few side effects or problems.

One significant aspect of an IUD is that we can also remove it whenever you'd like, such as if you're ready to get pregnant, and fertility returns promptly. They're also mistake-proof, meaning you can't forget to take it like the pill and don't have to remove it once a month like a vaginal ring.

Although you may experience some side effects following IUD placement, they're usually mild. For example, common side effects of the hormonal IUD include heavier-than-normal bleeding and spotting between periods.

Two types of IUDs and how they work

There are two forms of IUDs – copper and hormonal. Both are 99% effective in preventing pregnancy, but they work in different ways to do so.

A hormonal IUD slowly releases a synthetic form of progesterone through the stem of the device. Progesterone is a naturally occurring hormone in the female body that's vital in regulating the menstrual cycle.

Hormonal IUDs work in several ways to prevent pregnancy. The excess progesterone thickens cervical mucus, which traps sperm and prevents them from reaching an egg. This IUD also prevents ovulation, which is necessary to achieve pregnancy, and thins the uterine lining, which makes it inhospitable to a fertilized egg if conception were to occur.

The nonhormonal copper IUD is the same shape, but it has copper wrapped around its stem. This metal affects the way sperm cells move, which keeps them from reaching an egg.

An IUD can also be used as emergency contraception if it’s placed within five days of unprotected sex.

Which one is right for me?

The main difference between the two types is the use of hormones and how long they prevent pregnancy. 

If you're looking to avoid hormonal side effects and want an option that lasts about 10 years, the copper IUD is a good fit. Many women choose this if they plan to wait several years to start a family or don't want any more children.

A variety of hormonal IUDs are available, and they vary in how long they last, about three to five years. You may opt for a hormonal IUD if you experience uncomfortable PMS symptoms like heavy cramping or bleeding. Some women stop menstruating entirely with hormonal IUDs.

Contact Inga Zilberstein, MD, today to discuss IUD placement by calling or texting 830-254-5941. You can also send a message through our website.