As mentioned in this post, progesterone and estrogen are key hormones in the menstrual cycle. Hormonal contraceptives use progestin (the synthetic version of progesterone) and estrogen, either alone or combined, to avoid pregnancy. This is achieved in different ways [1,2]:
Having constant release of progestin stops the secretion of gonadotropin, which reduces the amount of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These low levels prevent the start of the ovulatory phase (read more about the menstrual cycle here). Since the egg can not leave the ovaries, the sperm will not be able to fertilize it.
Both progestin and estrogen (although estrogen is not as effective) thickens the cervix, stopping the sperm from getting through to get to the egg.
However, it is important to understand that using hormonal contraceptives does not mean that eggs cease producing. The follicles are simply broken down and reabsorbed by the ovaries (read more about the ovarian cycle here) [3]. On the other hand, using hormonal contraceptive doesn’t affect your fertility later on [3,4]. Once you get off the hormonal contraceptive, your body will eventually return to normal.
There are different types of hormonal contraceptives, each with advantages and disadvantages. Let’s take a look!
Birth control implant (99% effective [5])
The implant is a small and thin rod the size of a matchstick that is inserted inside the arm by a nurse or a doctor. The rod contains progestin which releases into the body over the span of 3 to 5 years [6,7]. Other methods of birth control should be used during the first week unless the implant is secured within the first 5 days of menstruation [8]. Moreover, Rifampin (a type of antibiotic) can negatively affect its effectiveness.
Birth control shot (96% effective [5])
The shot contains progestin and needs to be injected every 12-13 weeks by a healthcare professional [6]. Getting the first shot administered within the first 7 days of menstruation, protection is immediate. Otherwise, using additional birth control for a week is required. There are some medications that make the shot less effective [9], therefore, it is important to consult with a doctor.
Vaginal ring (93% effective [5])
The vaginal ring is a small and flexible ring that is inserted inside the vagina by releasing progestin and estrogen into the body. There are two types of rings [10]:
NuvaRing lasts up to 5 weeks.
Annovera lasts up to 1 year, leaving it in for 21 days and taking it out for 7.
There are some medications that make the vaginal ring less effective [11], therefore, it is important to consult with a doctor if you are taking or need to take medications. Also, estrogen might lower the amount and quality of breast milk in the first 3 weeks of breastfeeding. Therefore, it is important to wait a few weeks after beginning breastfeeding to use the ring again.
Birth control patch (93% effective [5])
The transdermal contraceptive releases estrogen and progestin through the skin to prevent pregnancy [6]. A new patch is placed every week for 3 weeks and for the fourth week, no patch is placed (menstruation will happen during this time).
Birth Control Pill (93% effective [5])
There are two types of birth control pills, one with both estrogen and progestin and the other progestin-only. Combination pills come in a package of 21 or 28, depending on whether it includes a week of placebos [15]. Taking them once a day around the same time is better, although not necessary. On the other hand, most progestin-only pills need to be taken within the same 3 hours every day to be efficient, and, they only come in packages of 28 with no hormone-free week.
Starting this birth control can be anytime during the cycle, although depending on the type of pill, the use of another birth control method might be needed for the first 7 days [14]. It is important to note that certain medications and supplements can interfere with the efficacy of the pill, as well as diarrhea or vomiting for more than 48 hours, as they are not being properly absorbed [13].
Sides effects of hormonal contraceptives
Hormonal birth control may cause mild side effects for some people, although it usually goes away after a few months once the body adjusts. The most common side effects are [15]:
Spotting (light bleeding or brown discharge), especially during the first 6-12 months.
For some people, periods are lighter, and for others, they stop completely. This is safe as even though the endometrium is not shedding, follicles are still being developed and reabsorbed.
Headaches.
Breast tenderness.
Nausea.
Weight gain.
Depression or mood changes.
Since combined contraceptives have low doses of estrogen and progestin compared to past doses, the risk of complications have decreased. As a result, these are now considered as a very reliable and safe option for most people [15]. However, even though results are inconclusive, it is important to note that there may be a very small increased risk of blood clots and breast cancer [15]. Therefore, due to this increased risk, it is better to avoid combined hormonal contraceptives when:
older than 34.
smoking - this already leads to a higher risk for blood clots or a heart attack.
having had blood clots or a stroke in the past.
having a history of “estrogen-dependent” tumour like breast or uterine cancer.
having abnormal or unexplained menstrual bleeding - this should be investigated further.
having a liver disease.
having migraines with other neurological symptoms - this already increases the risk of stroke.
Between hormonal and non-hormonal contraceptives (read more about these here), there are plenty of options to chose from. Nevertheless, keep in mind that condoms (internal or external) are the only contraceptives that protect against STDs. Check out the advantages and disadvantages of each method, and remember, “dislike it? change it!” However, when switching methods or taking medications, we highly recommend talking to a healthcare provider.
Even though we have already discussed many different methods, we are still missing Intrauterine Devices (IUDs). This topic will be examined next week!
--------—-----------------------------------------------------------------------------
Written by: María
Edited by: Natasha
BioDecoded is aware that Birth Control has generated much controversy and litigation, but we believe accurate information about the mechanisms of action and safety can allow our readers, especially women, to make more informed decisions. We cannot offer any specific health advice. If you have any doubts about your personal health, please speak with your healthcare professional or family physician. Your doctor can revise your medical history and advise you on the best path to follow. If you have any questions about this topic or would like to learn more, please comment below or send us your questions.
References:
Cooper, D., et al (2022). "Oral Contraceptive Pills", StatPearls Publishing. Available at: https://www.ncbi.nlm.nih.gov/books/NBK430882/
Keller S. (1995). “Progestin-only methods are very effective”. Netw Res Triangle Park N C;15(4):4-8. Available at: https://pubmed.ncbi.nlm.nih.gov/12289832/
What happened to my eggs? (2022). Bourne Hall Fertility Clinic. Available at: https://www.bournhall.co.uk/fertilityblog/what-happened-eggs/ (Accessed: 26 March 2023).
Girum, T. and Wasie, A. (2018) "Return of fertility after discontinuation of contraception: a systematic review and meta-analysis", Contraception and Reproductive Medicine, 3(1). Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6055351/
Birth Control Methods & Options | Types of Birth Control (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control (Accessed: 26 March 2023).
Contraception (2023). CDC. Available at: https://www.cdc.gov/reproductivehealth/contraception/index.htm (Accessed: 26 March 2023).
Birth Control Implants | Nexplanon Information (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-implant-nexplanon (Accessed: 26 March 2023).
What Happens After Birth Control Implant Insertion? (2023). Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-implant-nexplanon/what-happens-when-the-birth-control-implant-is-inserted (Accessed: 26 March 2023).
What is the Effectiveness of Depo-Provera? (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-shot/how-effective-is-the-birth-control-shot (Accessed: 26 March 2023).
NuvaRing | Birth Control Vaginal Ring | Estrogen Ring (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-vaginal-ring-nuvaring (Accessed: 26 March 2023).
What is the Effectiveness of the NuvaRing? (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-vaginal-ring-nuvaring/how-effective-birth-control-ring (Accessed: 26 March 2023).
Are Birth Control Pills Effective? | Do Birth Control Pills Work? (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-pill/how-effective-is-the-birth-control-pill (Accessed: 26 March 2023).
Are Birth Control Pills Effective? | Do Birth Control Pills Work? (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-pill/how-effective-is-the-birth-control-pill (Accessed: 26 March 2023).
How to Use Birth Control Pills | Follow Easy Instructions (2023). Planned Parenthood. Available at: https://www.plannedparenthood.org/learn/birth-control/birth-control-pill/how-do-i-use-the-birth-control-pill (Accessed: 26 March 2023).
Patient education: hormonal methods of birth control (beyond the basics) (2023). UpToDate. Available at: https://www.uptodate.com/contents/hormonal-methods-of-birth-control-beyond-the-basics (Accessed: 26 March 2023).
Comments