US Pharm. 2022:47(9):15-16.



Preventing Unwanted Pregnancies

There are several contraceptive options to consider when it comes to preventing unwanted pregnancy (UP). All options differ in their level of effectiveness and for how long they provide protection. Long-acting, reversible contraceptives last several years and provide highly effective protection from UP. Birth control implants and intrauterine devices (IUDs) are two types of long-acting contraceptives with effects that are reversible when removed from the body. Birth control implants are small, hormone-infused rods placed just under the skin in the upper arm, whereas IUDs are placed directly into the uterus and may or may not contain hormones.

History of IUD Use

The first documented use of an IUD to prevent pregnancy dates to 1909, when a ring made of silkworm gut placed in the uterus reduced the pregnancy rate to 3% in women who used the device. Many years later, and after many technological advances, a product named the Dalkon Shield was developed and marketed to women in the United States. It was quickly pulled from the market after reports of many serious side effects, including infection and infertility. The use of IUDs slowed significantly in favor of other forms of contraception until 1995-2000, when two new types of IUDs were introduced and gained popularity.

IUDs prevent fertilization of the egg by either preventing sperm from reaching the fallopian tubes or preventing the release of the egg by the ovary. There are two types of IUDs available today. A nonhormonal variation uses copper, and the other variation releases the hormone progestin.

Copper-Containing IUDs Do Not Contain Hormones

Copper-containing IUDs are small, T-shaped devices that are inserted directly into the uterus by a medical professional. Copper ions from the device create an inhospitable environment for egg implantation and one that is toxic for sperm. Copper IUDs can remain in the uterus for up to 10 years, providing long-term pregnancy prevention. The failure rate of copper-containing IUDs is approximately 1% to 2%, with most failures occurring in the first year after insertion. This failure rate is very low and comparable with the pregnancy rate for women who have undergone a sterilization procedure. Copper IUDs have also been used as an emergency contraceptive when placed within 120 hours of unprotected intercourse.

Though generally safe, the copper-containing IUD is not without side effects and risks. The most common potential side effect is increased cramping and bleeding associated with the menstrual cycle. In rare instances, uterine perforation and infection have occurred with copper IUD use. Copper-containing IUDs can be used by women who are medically unable to use progestin or who prefer to avoid synthetic hormones.

Hormone-Containing IUDs Can Reduce Bleeding

Four versions of hormone-releasing IUDs are available in the U.S., and all are designed to release a small amount of the progestin hormone levonorgestrel each day. The hormones work locally in the uterus by increasing the thickness of the cervical mucus, inhibiting the sperm’s ability to move and interact with the egg. Additionally, the hormone-containing IUDs can change the lining of the uterus, making it notably thinner. As a result, many who use them may stop menstruation.

These IUDs can be used for up to 5 years and can be removed at any time to allow a woman to return to normal fertility. The failure rate for these devices is below 1% over 5 years. Just like copper-containing IUDs, these devices can have side effects and other risks. The most common side effects leading to discontinuation of the hormone-containing IUDs include expulsion of the device, bleeding, acne, and mood swings. Rare cases of uterine perforation and infection have also occurred.

IUDs may be a viable contraceptive option for individuals looking for long-acting pregnancy prevention without the risk of missed doses and user error. Both the benefits and the risks of IUDs for contraception should be discussed with a healthcare provider.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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