Though not as well known as the Pill or the IUD, the birth control patch is often touted as a good option for women who have trouble remembering to take a daily pill but do not want the more invasive hormonal or copper IUD. Around ten percent of women report that they’ve used the patch to prevent pregnancy, and that percentage has ticked up slowly over the past twenty years. What makes the birth control patch different from other forms of hormonal birth control? And is it really a good option for pregnancy prevention, or could it’s estrogen-related side effects actually cause more harm than good?
How does the birth control patch work?
The birth control patch is a small sticky patch that attaches to your skin and secretes artificial versions of the hormones estrogen and progesterone. These versions aren’t bioidentical or biomolecularly identical, which means they impact the body differently than natural estrogen and progesterone do. Xulane and Twirla are the two generic brands for the patch in the United States, with little difference between the two.
At the beginning of each month, you’ll place a new patch on your body (usually on the back of the arm, leg, torso, or buttock) and swap it for a new one at the beginning of the following week–and then again the week after that. After those three weeks of patch-wearing have passed, you’ll take a week off in order to have a “period.” However, this bleeding is not a real period (and more aptly termed a “withdrawal bleed”), as women on birth control don’t experience a natural cycle.
The patch is very similar to both the combination birth control pill and the vaginal ring because it contains both estrogen and progestin. Instead of ingesting these hormones in a pill, they are secreted into the skin from the patch and absorbed into the bloodstream. Many women choose the patch for this exact reason — it seems more convenient and easier than remembering to take a pill every day or having an invasive procedure to insert an IUD or vaginal ring. Unfortunately, it is this feature (the absorption of the hormones directly into your skin) that actually makes the patch a more dangerous contraceptive option than its counterparts.
Unfortunately, it is this feature (the absorption of the hormones directly into your skin) that actually makes the patch a more dangerous contraceptive option than its counterparts.
More estrogen is absorbed via birth control patches versus other birth control methods
Estrogen is known to increase the risk of blood clotting. Why is that? Let’s first look at how all hormonal birth control methods prevent pregnancy. Without ovulation, there can be no pregnancy, so all HBC methods function primarily by “telling” the body not to ovulate. They do this by blocking the hypothalamic-pituitary-ovarian (HPO) feedback loop.
But how does that relate to blood clotting? Stay with me. What’s a major reason the body would not be ovulating? Pregnancy. And when you’re pregnant, the increase in natural (endogenous) estrogen that occurs also causes the body to produce more clotting factor proteins. Why? In order to assist with any bleeding episodes that might occur during a potential miscarriage or during childbirth.
The artificial, constant, small doses of external (exogenous) estrogen from birth control likewise cause more blood clotting factor protein production within the body. This similarly raises one’s blood clot risk, but unnecessarily so, as there’s no biological need to prevent hemorrhage as there is with pregnancy. A blood clot might not sound like a big deal, but it can cause blockages of blood flow and oxygen to vital body parts, like your lung(s), brain, heart, and/or legs.
Estrogen absorption from the birth control patch is 60% higher than from the Pill
Blood clots are a risk all women on hormonal birth control face. But the risk happens to be much higher with the patch. This is because the amount of estrogen absorbed from the patch is 60 percent higher than the amount absorbed from the Pill [1]. That’s why, in December 2011, the FDA issued a warning stating that the Ortho Evra patch carries an increased risk of blood clotting due to the higher estrogen absorption that occurs for women using the patch.
Women using the Pill already experience a three-fold increase of blood clotting compared to non-users, and that risk further doubles for women who are using the patch instead. Tragically, there have been countless cases of women losing their lives due to blood clots or clot-related strokes after using hormonal birth control. It’s especially important for women with a family history of blood clots to understand the increased possibility of these dangerous effects when using the patch for birth control.
Besides blood clot risk, the other side effects of the birth control patch are largely similar to those of the Pill and other hormonal birth control methods. They include breast pain, headaches, nausea and vomiting, mood swings, weight gain, fatigue, and acne. However, the increased estrogen absorption from the patch can also increase the intensity of some of the estrogen-related symptoms that come with hormonal birth control. Specifically, studies have found a 3.7% increase in dysmenorrhea (menstrual pain) and a 12.9% percent increase in breast pain in patch users compared to women taking the Pill [1].
Why the patch’s typical-use pregnancy prevention rate is less than the Pill
Two other important notes about the patch are that it only works for women whose body mass index (BMI) is less than 30, and its effectiveness rate is 91% with typical usage. The patch losing stickiness and coming off due to rubbing on clothing or being in water for long periods of time are two common reasons for decreased effectiveness. Perfect use effectiveness rate is 99%.
Women who wish to manage their fertility without putting themselves at risk for deadly blood clots and other side effects have other options. Fertility Awareness Methods (FAMs) also boast high effectiveness rates. For example, the Sympto-Thermal method (which tracks basal body temperature, BBT, and cervical mucus) has a perfect use rate of 99.6% and a typical use rate of 98.2% [2]. The Marquette model, which uses a digital fertility monitor which tests levels of luteinizing hormone (LH) in the urine, has a failure rate of only 0.1% for perfect use!
Not only are FAM methods effective, but they’re also helpful for learning more about your health, whether for fertility monitoring, mitigating PMS symptoms, or treating a menstrual disorder. The birth control patch can bring with it a host of unwanted side effects that are only magnified by the increased absorption of estrogen, but choosing a FAM instead can actually help you decrease some of those symptoms.
This article was last updated on February 6th, 2024, to clarify that the concern with the estrogen and progestin found in hormonal birth control isn’t that it’s synthetic. The concern is that the hormones are biomolecularly different (and therefore act differently) than the body’s own estrogen and progesterone.
References:
[1] Wooltorton E. The Evra (ethinyl estradiol/norelgestromin) contraceptive patch: estrogen exposure concerns. CMAJ. 2006 Jan 17;174(2):164-5. doi: 10.1503/cmaj.051623. Epub 2005 Dec 20. Erratum in: CMAJ. 2008 Jun 17;178(13):1688. Dosage error in article text. PMID: 16368722; PMCID: PMC1329453. [2] P. Frank-Herrmann, J. Heil, C. Gnoth, E. Toledo, S. Baur, C. Pyper, E. Jenetzky, T. Strowitzki, G. Freundl, The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study, Human Reproduction, Volume 22, Issue 5, 1 May 2007, Pages 1310–1319, https://doi.org/10.1093/humrep/dem003Additional Reading:
FAM Basics: Your hormones during a natural cycle vs. your hormones on the Pill
How the IUD, implant, pill, and other birth control methods work
