Anna’s work-in-progress guide to hormonal birth control

Credit: Anabelle Kang/ Credit: Anabelle Kang/

Full disclaimer: I am not a medical professional and do not claim to be one. This article is meant only to be a helpful summary of findings based on literature I take to be trustworthy. As you’ll soon learn, birth control is highly personal. Nobody will have the same response to any one type of medicine, and under no circumstances should any form of birth control be taken as 100 percent protection against pregnancy or sexually transmitted diseases or infections. I will also not be commenting on STD prevention in this article because that can only be achieved by barriers and regular testing (and neither are considered reliable protection against pregnancy). I will also not be commenting on non-hormonal options like vasectomies, condoms, abstinence, etc., with the exception of the copper IUD. With that said, I hope I can use what I’ve learned to shed some light on the medical fogginess that is hormonal pregnancy prevention. There is a lot to say about birth control; this is just some of it. Here goes:

Estrogen does not prevent pregnancy.

There, I said it. I know, you’re completely shocked. You’re calling your mom and your middle school health teacher. You’re yelling at random people on the street. Or maybe you’re cooler than I am and you already knew that the only hormone that prevents pregnancy is progestin. Progestin prevents ovulation, which is the release of an egg from the ovary into the uterus, where it could potentially access sperm and become fertilized (read: a baby). Progestin stops this entire process, which halts the menstrual cycle as well, since a period is just a means to getting the egg out of the uterus when it’s been sitting there, not being a baby, for too long. Also, notice that I used the word “halt.” This means that if you’re on a form of birth control that allows you to stop and bleed once a month, you are not having a period; there is no egg to release. Birth control bleeding happens because when you take your break week, the sudden lack of hormones tricks your body into thinking it’s time to bleed, since the normal cycle takes a hormone dip just before the period.

So why are we even talking about estrogen when progestin is obviously the star of the show? The thing is that estrogen is important for a lot of things. It is the key player in the circular dance of the female reproductive cycle, moving up and down in elegant and predictable patterns every month. That’s why some birth control methods include estrogen — not because it actually controls birth, but because it can supplement and stabilize you when you’re using medication to intentionally change your cycle. In the right doses, it keeps your bones healthy, clears up your skin, lowers the risk of certain cancers, and turns you into Cinderella at midnight. Obviously, I’m not sold. Estrogen can be damaging to the stomach and cause the “brain fog” or depression that is listed as a side effect on some birth control methods. The point is that choosing a method of birth control is not just about how convenient or effective it is, but also about considering what ingredients you’re ingesting and how they will affect your body, mind, and the inner werewolf that’s controlled by the cycles of the moon.

Also, estrogen in medications is called ethinyl estradiol. Progestin is just one of a family of hormones called progestogens and is replaced in medications by levonorgestrel (which is actually similar to testosterone). Do not panic when you see these molecules listed on birth control packaging: They are synthetic derivatives of the real deal, chosen because of their ability to deliver similar results. However, do be aware that they are not identical and should not be treated as such.

Some forms of hormonal birth control are seemingly localized to the fertilization organ: the uterus. These include Intrauterine Devices (IUDs) and the ring.

The hormonal Intrauterine Device (IUD; as opposed to the non-hormonal version), uses progestin to thicken cervical mucus as it sits inside the uterus. It can also prevent ovulation, which is typically the end game of birth control, but since the hormones are so localized to the reproductive organ, it takes a more physiological route: using the mucus as a physical barrier against sperm. The hormone sits in a little vial inside the device and leaks out at a controlled rate over the course of five to eight years, depending on the brand. Because the delivery is so constant, if it does prevent ovulation for you, it will stop your period or significantly shorten it. It must be inserted and removed surgically, and can become infected or release itself over time.

The non-hormonal IUD uses copper, which apparently sperm really hate. The release of copper ions into cervical mucus essentially makes it spermicidal. Science is neat, and in this case 99 percent effective!

The ring is deceptive: even though it sits right in the cervix, it releases hormones (both estrogen and progestin) directly into the bloodstream through the walls of the vagina. Despite how weird it may seem to keep something up there for so long, it really will not move until you pull it out because it is shaped the same as the area where the vagina meets the cervix. It stops ovulation and should be taken out once a month to allow for bleeding. Depending on the brand, you can replace the ring the next month with the same one you’ve been using for up to a year or a new one each month. It is 93 percent effective.

Some forms of birth control release hormones constantly throughout the body. One such example is the implant, which is placed (and removed, both surgically) in the upper arm, and works similarly to the hormonal IUD except that the progestin it contains runs through the entire body as opposed to being localized in the uterus. This means that it definitely stops ovulation (with a 99 percent pregnancy prevention rate) while also thickening cervical mucus. It can be kept for about five years.

No matter how many sources I look at, I cannot wrap my head around how the Depo-Provera shot actually works. Like some of the other options I’ve talked about, the shot is just slow released progestin, but for the life of me I cannot understand how they can inject three months of a hormone into your bloodstream and expect it to release at a constant rate. Like so many things with birth control, this one might just remain an unfortunate and kind of misogynistic mystery. What I do know is that it lasts three months, is 96 percent effective, and is given just like any other injection.

The patch works similarly to the ring, and is 93 percent effective. It needs to be replaced every week, skipping every fourth week for bleeding. It releases both progestin and estrogen and can be placed on the back, the butt, or the shoulder.

Then there’s the birth control pill. I could say a lot about the pill, mostly because there isn’t just one, contrary to popular belief. The list of pills may be long, but they all differ in the same respect: the ratio of hormones they contain. Every pill contains progestin, though not always in the same amount. Not all pills contain estrogen. Pills that contain estrogen are known as combination pills. Pills that do not are known as progestin-only. They can be prescribed for a myriad of different purposes, with the hormonal ratio changing depending on what you need. The main difference is that you must take progestin-only pills exactly 24 hours apart, whereas there is a little more leeway with combination pills because estrogen acts as a stabilizer. You take the pill every day for three weeks and then take a one week break. The pill is considered to be 93 percent effective because of the potential for forgetting a pill or taking one late. If you’re going to take the pill, you’d better be good at remembering to do it at the same time every day, and you’d better not make the mistake of taking the first pill on the list without deciding which ratio of hormones is right for you. You can also use some pills (and some patches) to skip your periods by continuing to take them with no break. Do this only with the knowledge that you are disrupting a cycle that your body considers extremely important.

In fact, take any of these options with that knowledge. Pregnancy was never meant to be prevented, and doing so by tampering with the extremely complex female reproductive cycle has consequences. For those of you who are currently yelling “What about male birth control!?”, new research announced this February shows promising options for temporarily disabling sperm mobility. Maybe the time has finally arrived for uterus-havers to not have to worry about the last 1,000 words I just wrote. For now though, I hope I’ve been able to spit some facts for anyone feeling like Carnegie Mellon is not the place to raise a baby.