Hormonal Birth Control Break Down

What is hormonal birth control and how does it work?

Hormonal birth control is a general term for all contraception methods that use steroid drugs to suppress ovulation and prevent pregnancy, including tablets, patches, injections, some intrauterine devices and the vaginal ring.

Hormonal birth control (HBC) works to prevent pregnancy by stopping ovulation, preventing the formation of fertile mucus and/or thinning the uterine lining. 

The steroid drugs (or pseudo-hormones) in birth control travel to the pituitary gland and prevent the pituitary from releasing luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Without the release of these hormones, ovulation does not occur. Luteinizing hormone is responsible for signaling to your ovaries to release an egg and follicle stimulating hormone is responsible for stimulating ovarian follicles to grow (each ovarian follicle contains one egg and produces estrogen, progesterone and testosterone).

No ovulation = No pregnancy

but it also means,

No ovulation = No period

The following comes from 'TAMING THE CYCLE: HOW DOES THE PILL WORK?' published on Hardvard.Edu and is worded so well, I thought I would include it here: "Although the outward appearance is the same (menstrual bleeding in week 1 of a 28 day cycle) the constant high levels of P and E for a woman taking the Pill actually abolish the normal hormonal cycling that underlies ovulation. The Pill therefore replaces the normal menstrual cycle with an artificial cycle (3 weeks of “mimicking pregnancy”, followed by 1 week with breakthrough bleeding)." [1]

What this means is you do NOT have an actual period while on hormonal birth control because you do not ovulate. A period is the result of a series of hormonal events in the body, including ovulation. Hormonal birth control is not "regulating" your hormones, or "normalizing" your period. Instead, it's shutting down your natural hormonal system. You are having a withdrawal bleed from the pill steroids when you do bleed on hormonal birth control. 

What are you missing out on by not producing your natural hormones? Estradiol is produced by your ovarian follicles and it stimulates mood and libido by increasing the neurotransmitters serotonin and dopamine. Estradiol also benefits your bones, muscles, brain, skin, sleep and metabolism. After you ovulate, the emptied follicle forms into the corpus luteum which produces progesterone. Progesterone helps to boost thyroid hormone, reduce inflammation in the body, supports sleep and helps to calm the nervous system (progesterone converts to allopregnanolone which is a calming neurosteroid). As you'll read in a bit, synthetic estrogen and progestin do not have these benefits in the body.

So why do you bleed every 28 days when taking birth control then?

Back when the pill was created, it was marketed for “cycle control” since contraception was not yet legal in the U.S.. Socially, legally and politically contraception was taboo thanks to the Comstock Law (which lumped talking about contraception with pornography). In Canada, the pill was available by 1960 for “menstrual regulation” but it wasn’t legal to even discuss contraception or prescribe the pill for contraception purposes until 9 years later in 1969. So since the pill had to be marketed to "regulate menstruation" it was designed to mimic a woman's natural cycle. [2]

Having a withdrawal bleed on the pill also helps to prevent break through bleeding, but it does not need to be every 28 days – as you can see from pills like Seasonique, which give the user a withdrawal bleed once every three months.

Before I dive into the steroid drugs in hormonal birth control, let's talk about a bit more about your natural hormones first. 

The natural ovarian hormones are estradiol and progesterone.

Estradiol is released by the developing ovarian follicles. Estradiol stimulates the uterine lining to grow and thicken, as well as stimulates the production of fertile mucus. (Fertile mucus has the main purpose of helping sperm to survive and travel to the egg.) 

Progesterone is a steroid hormone made by the corpus luteum (a temporary endocrine gland). Progesterone is essential for pregnancy, but also counterbalances estrogen and thins the uterine lining, as well as produces infertile mucus. Progesterone has many benefits to the body outside of supporting a healthy menstrual cycle and pregnancy. Progesterone protects brain and nervous system tissue, is a natural anti-inflammatory agent, and promotes deep sleep. 

Steroid drugs in hormonal birth control, also known as pseudohormones include ethinylestradiol and progestin (which comes in many different forms, which I'll list below).

Steroid drugs are chemical messengers, but they are NOT human hormones. They are in fact different molecules and different molecules have different effects in the body. The term 'progestin' is used to describe all molecules that are similar to progesterone. But here's the thing, when comparing the levonorgestrel molecule (a type of progestin) side by side to the progesterone and testosterone molecules, levonorgestrel is actually more similar to testosterone than it is progesterone. So while progesterone does some amazing things for your body like promote hair growth, levonorgestrel actually causes hair loss. [3]

Please do not be tricked into believing progestin and progesterone are the same thing.

Types of Progestin Include [4]:

  • Norethindrone
  • Norethindrone Acetate
  • Ethynodiol Diacetate
  • Levonorgestrel - most widely prescribed contraceptive progestin worldwide, and more similar to testosterone than it is to progesterone
  • Norgestrel
  • Desogestrel
  • Norgestimate
  • Drospirenone



Which means you won't get the amazing benefits of progesterone listed earlier. 


Different Types of Hormonal Birth Control

So now that I've covered real hormones versus pseudo-hormones I'll break down the different types of hormonal birth control available.

  1. Combined (Estrogen Plus Progestin)

Combined hormonal birth control is a combination of two pseudohormones; ethinylestradiol plus one of the types of progestin listed above.

Examples of combined birth control:

  • The Pill
  • Nuvaring
  • Contraceptive Patch

What makes all of the different combined HBC options different? The amount and timing of estrogen and the type of progestin (and of course the delivery method) are what differentiate the different types of combined hormonal birth controls. 

*A note about delivery method: Hormonal birth control that is not consumed orally and is instead placed directly on the skin or in the vagina, deposits the steroid drugs (pseudo-hormones) directly into the blood. This means they are not first being filtered through the digestive system and liver. 

2. Progestin Only

How do progestin only methods of birth control work? They prevent pregnancy by thinning the lining of the uterus (a thin uterine lining can not support a pregnancy) and impairing the production of cervical mucus (without cervical mucus sperm cannot travel to the egg).

Examples of progestin only methods include:

  • Progestin Only Pill (also known as the mini-pill)
  • Implants
  • Injections
  • IUDs – Mirena and Skyla

Side Effects

Major Side Effects

  • Blood Clots
    • The risk of blood clots has existed since HBC came into existence. Each new generation of progestin is supposed to be better, but it seems that each new generation actually carries a greater risk of blood clots. Transdermal patches and vaginal rings carry the highest risk of blood clots, with a 7.9 and 6.5 times increased risk, compared to nonusers of hormonal birth control [5]. Patches and vaginal rings dispense psuedo-hormones directly into the blood stream, unlike the pill which results in psuedo-hormones being processed by the digestive system and liver first. if you're debating using the NuvaRing, I encourage you to read this article first.
  • Cancer
    • A recent study in Denmark confirmed that the risk of breast cancer is increased with the current or recent use of hormonal contraceptives and the risk increases with longer durations of use. [6] A high dose estrogen pill increases your risk for breast cancer by three times. [3]

"Minor" Side Effects

  • Depression
    • The onset of depression can happen within one day or one year of taking hormonal birth control. A study in Denmark that tracked over 1 million women, ages 15 to 34, over a 13 year period found that women who use hormonal birth control, especially adolescents, are more likely to be diagnosed with depression. [7] This diagnosis peaked after six months of using HBC. And keep in mind, this study only included the women who went on to be diagnosed with depression and take antidepressants. It did not include the women who experienced changes in mood or an onset of depression and failed to report it. It makes sense that hormonal birth control would cause depression as it shuts off our natural estrogen production, which boosts are feel good neurotransmitters, and lowers our natural testosterone production. 
  • Hair Loss
    • Hair loss is caused by hormonal birth control with progestins that have a high androgen index. Remember above when I said the progestin molecule is actually more similar to the testosterone molecule than it is to the progesterone one? Well, some progestins have a high androgen index meaning they are even more testosterone like. These types of progestins slowly shrink your hair follicles over time leading to hair loss (meaning it may be months of years before you begin to notice). This is not an easy thing to reverse. Excess androgens may also lead to acne.
  • Loss of Libido
    • Remember above when I said your ovarian follicles produce testosterone? And you need FSH to stimulate the ovarian follicles to grow? Without FSH stimulating your ovarian follicles to grow, your ovarian follicles can't produce testosterone. Testosterone increases your libido (and also helps to improve your mood and energy levels so with a lack of testosterone you may not only see lack of libido, but depression and fatigue). Not only do you not produce testosterone, but you may end up with elevated levels of sex hormone binding globulin (SHBG). SHBG binds to excess hormones in the body, making them unavailable for use. Your body naturally produces more SHBG when you are on hormonal birth control to help keep you safe from the high ethinylestradiol (synthetic estrogen) levels in HBC [8]. Studies have shown SHBG levels stay elevated even after coming off of hormonal birth control. The use of hormonal birth control has been associated with less frequent sex, less frequent feelings of arousal, pleasure, orgasm, and vaginal lubrication [9]. It seems a little ironic that hormonal birth control allows us to have sex with out risk of pregnancy, but causes a lack of interest in sex!
  • Weight Gain
    • Hormonal birth control has been shown to contribute to insulin resistance. Insulin resistance is when there is too much insulin in the body and it leads to inflammation and weight gain (if you have PCOS this is a topic worth doing more research into, as increased insulin impairs ovulation and causes your ovaries to make testosterone instead of estradiol). 

Side Effects Specific to Certain Types of HBC

  • The Pill (specifically Yaz and Yasmin)
    • Common side effects include anxiety and depression - and possibly blood clots. If you're considering Yaz or Yasmin, please read this.
  • Nuvaring – blood clot risks much higher than the pill
    • Contains the progestin etonogestrel (a form of desogestrel which is a third generation progestin) which carries a higher risk of blood clots than earlier generations of progestin
    • Ethinylestradiol goes directly into blood stream, meaning it does not pass through the liver
    • Nuvaring dispenses hormones directly into blood stream vs. the pill that loses up to half it’s hormones in digestive system
  • Contraceptive Patch
    • Carries a higher risk of blood clots because hormones are released directly into the blood stream
  • Implants
    • Has been shown to cause weight gain and erratic bleeding
  • Injections
    • Has been shown to cause unstoppable weight gain, temporary bone loss, and carry the risk of breast cancer

A word about hormonal birth control and labels

“Americans may assume that the fine print in a drug’s packaging represents the collective scientific knowledge about that medication, allowing doctors and patients to make informed health care decisions. In fact, negotiations between pharmaceutical companies and the FDA over warning labels are common during the drug approval process, with drugmakers endeavoring to cherry-pick what’s included in order to present their products in the best possible light.”[10]

It's sad but true, the labels on hormonal birth control do not tell the entire story.

When to go on HBC

From reading this blog, you can clearly tell I am not a fan of hormonal birth control. However, it is your body and your choice. Please ask yourself, is the risk worth the reward? You may have read all of the above and have decided that taking hormonal birth control is still the best option for you in order to prevent pregnancy (I'll be covering non-hormonal birth control options in a blog post next week!). Or you may have decided hormonal birth control is the best option to handle your period problems. If you are dealing with a serious condition such as endometriosis or adenomyosis you may decide hormonal birth control is the best choice (however there are natural methods that do help - reach out to me to learn more!). 

Questions to ask your doctor

If you've read the above, and you're still deciding to use hormonal birth control please get specific information about the type of HBC your doctor is prescribing for you. Knowledge is power. The questions below are a good starting place to get more information.

  • Why are you choosing this specific hormonal birth control to prescribe me?
  • What type of progestin is in this hormonal birth control?
  • Is it a combination HBC or a progestin-only?
  • What are the most common side effects of this HBC?

What to do if you go on HBC

If you do make the informed decision to go on hormonal birth control I highly suggest tracking any signs and symptoms. You can do this in a daily journal or download one of the many period tracker apps available. Track things like weight, mood, libido, hair loss, skin and even sleep and cravings.


While I personally do not support the use of hormonal birth control, I believe it is a woman's right to choose and decide what we do with our own body. I wrote this blog to so you could make an informed decision, but please also know there is so much more information out there about hormonal birth control that I couldn't include for the sake of the length of this blog - so please continue to do more research. And as you are doing research be careful of where information comes from and who is funding the research (being mindful if the manufacturer of hormonal birth control is funding the research it's probably going to be biased). If you do decide to still continue with hormonal birth control after reading this, please keep track of any signs and symptoms you may experience and do research into the specific hormonal birth control your doctor is prescribing you. I believe decades ago that hormonal birth control was a step in the right direction for women's rights, but now 50+ years later it is an outdated method and better, safer options are available. Continuing with the theme of birth control this month, I'll be covering how to come off of hormonal birth control and what to expect, and non-hormonal birth control options, later this month. In the meantime, feel free to contact me with any questions at veronica@veronicamcnelis.com



[1] http://sitn.hms.harvard.edu/flash/2008/issue40/

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520685/

[3] Period Repair Manual Lara Briden ND

[4] https://www.verywell.com/different-progestin-types-906936

[5] https://www.ncbi.nlm.nih.gov/pubmed/22577198

[6] http://www.nejm.org/doi/full/10.1056/NEJMoa1700732

[7] https://www.ncbi.nlm.nih.gov/pubmed/27680324

[8] https://drbrighten.com/birth-control-pill-low-sex-drive/

[9] https://kinseyconfidential.org/hormonal-birth-control-sexual-functioningwhats-deal/

[10] https://www.huffingtonpost.com/2013/12/18/nuvaring-blood-clots_n_4461429.html