Hormones are chemical messengers found in the body. In the reproductive systems of people with vulvas, they regulate everything from libido to the menstrual cycle. In addition, synthetic hormones can be administered to people with vulvas who have natural hormonal imbalances, though they are primarily used as a form of contraception, or birth control.1
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Hormones in the Human Body
Estrogen is a hormone mainly produced by the ovaries, as well as by the adrenal glands in smaller amounts. It plays an integral role in the development of the body, and the reproductive system more specifically. Estrogen induces the development of secondary sexual characteristics such as breasts, pubic hair, and armpit hair, and also functions to regulate the menstrual cycle. As a part of the reproductive system, estrogen serves to thicken the endometrial lining of the uterus in order to prepare for the potential implantation of an egg, one of the first stages of pregnancy. Another important hormone, progesterone, which is produced by the corpus luteum in the ovaries, assists in this process. If a fertilized egg is not implanted, the amount of progesterone produced declines, the endometrial lining sheds, and a new menstrual cycle begins. However, if the fertilized egg does implant, progesterone aids the progression of the pregnancy.2
When people with vulvas have hormonal imbalances, they may experience side effects. For instance, individuals with low progesterone production may experience irregular menstrual cycles, spotting and pain when pregnant, and frequent miscarriages. Individuals with low levels of estrogen often experience infrequent menstruation, hot flashes, lack of vaginal lubrication, mood swings, and decreased libido. In contrast, high levels of estrogen can cause weight gain, fibroids, menstrual problems, and depression or anxiety, among other side effects. Birth control and hormone therapies provide synthetic versions of estrogen and progesterone to help balance changes in these natural hormones. We recommend consulting a doctor if you are experiencing multiple of these side effects.1
Hormonal Contraceptives Overview
There are two types of hormonal contraceptive methods: the combination, or “combo,” method, which contains estrogen and progestin, and the progestin-only method. Progestin is a synthetic hormone meant to mimic progesterone and act as it does in the body. Both forms prevent the ovaries from releasing an egg during ovulation and thicken the cervical mucus to block sperm from entering the uterus and fertilizing the egg.3
Estrogen-Progestin Combination Contraceptive Methods
Combination birth control methods include combination pills, vaginal rings, and birth control patches, each of which have varying amounts of hormones. Although contraceptives with both low and high estrogen levels provide the same amount of protection from pregnancy, they each have different drawbacks and benefits that should be considered. Contraceptives with higher levels of estrogen are usually associated with an increase in health risks, while contraceptives with lower levels of estrogen do not regulate the menstrual cycle as efficiently. Talk to a healthcare provider for a complete list of estrogen-progestin contraceptive options.4
Effectiveness
Among the population using any of the progestin-estrogen combination birth control methods, studies have shown that with typical use (for example, forgetting to take a pill now and then), 92% are protected from pregnancy. With perfect use (i.e., using a given method exactly as it is intended), however, 99.97% of people using combination birth control methods are protected.5
Estrogen-progestin combination methods may benefit those who have or have had the following:
- Irregular or heavy menstrual periods
- Endometriosis
- Ovarian cysts
- Acne
- Iron-deficiency anemia
- Hot flashes
- A family history of ovarian cancer or endometrial cancer (combination pills are associated with an 80% reduction in the risk for ovarian and endometrial cancer when used for 10 years)
Consult with a doctor if you have had any of the above conditions and are interested in starting hormonal birth control.
Side Effects
Side effects of combination birth control methods may include light or skipped menstrual periods, spotting between periods, nausea and vomiting, headaches, weight changes, tender breasts, depression or changes in mood, and changes in sexual desire. Many of these side effects may decrease or disappear after the first few months of use. We recommend consulting with a healthcare provider about switching to a different method or dosage of contraception if symptoms continue.
Those using birth control containing estrogen are three to six times more likely to develop blood clots, so report to a doctor immediately if you experience any of the following, known as ACHES:
- Abdominal pain
- Chest pain
- Headaches
- Eye problems, including a blur or change in vision
- Severe leg pain or swelling
Combination contraceptive methods should NOT be used by those who have a family history of blood clots, breast cancer, high blood pressure, liver disease, or diabetes, or who are breastfeeding for the first six months following childbirth. In addition, people with vulvas over the age of thirty-five and smokers have increased risks of potential side effects.1
Progestin-Only Contraceptive Methods
Progestin-only birth control methods contain a very low dose of progestin and no estrogen. Progestin-only hormonal methods include the mini-pill, the implant (Nexplanon®), and the shot (Depo-Provera®).
Effectiveness
The progestin-only mini-pills are just as effective as combination hormone pills when taken perfectly; however, they must be taken at the same time each day, as the effects only last for twenty-four hours. There is also no hormone-free period of time, unlike many types of combination pills. The implant, a thin rod inserted under the skin, is over 99% effective for four years, at which point it needs to be replaced. The birth control shot must be administered every three months by a medical practitioner, and is 94% effective if used typically.4
Progestin-only methods may benefit those who:
- Are breast-feeding, since the low-dosage has no effect on the milk supply
- Are over thirty-five years old
- Smoke
- Are experiencing high blood pressure
- Have a history of blood clots
Consult a doctor if any of the above factors apply to you and you are interested in discussing progestin-only contraceptive methods.
Side Effects
Progestin-only methods typically have fewer side effects than combination methods, so they can be a good alternative for those who experience any adverse effects from other types of contraception. However, menstrual period irregularity is common in those taking progestin-only methods.1
Concluding Remarks
Hormonal birth control methods are a great way to prevent unwanted pregnancies and mitigate the effects of natural hormonal imbalances. There are many different contraceptive methods, and each one has unique benefits and drawbacks. If you are interested in getting started on hormonal contraceptives, consult a doctor to discuss which method will be best for you.
References
1. “What Are Hormones, And What Do They Do?” Hormone Health Network. N.p., n.d.
2. Baldwin, J., Baldwin, J., and LeVay, S. “Discovering Human Sexuality.” Massachusetts: Sinauer Associates, Inc. 2009.
3. “Hormonal Contraception.” Sex & U. N.p., n.d.
4. “Combination birth control pills Why it’s done.” Mayo Clinic. N.p., n.d.
5. “Birth Control Methods – Birth Control Options.” Planned Parenthood. N.p., 15 Dec. 2016.
Last Updated: 24 May 2022.