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The DL on the Combined Oral Contraceptive (COC) Pill

What I find ironic about the use of the Combined Oral Contraceptive (COC) pill is that in so many cases ‘contraception’ is not deemed the primary reason for use. In clinic, what I hear women saying is that they started it to ‘normalise’ their hormones. With conditions such as polycystic ovarian syndrome (PCOS), absent periods (amenorrhea), heavy bleeding (menorrhagia), acne, low iron levels and inconsistent periods top of the list. Let’s be clear though, the COC doesn’t normalise female reproductive hormones.

What it’s doing is shutting down ovarian hormone production, thereby stopping ovulation, creating a reversible state of infertility and quite possibly leaving a trail of unwanted effects. It’s the equivalent of reversible castration, which I’m sure to most men would sound like an absolute ‘no go’ zone. Unfortunately the use of the COC has become normalised and rationalised. The good news is that I’m starting to see the tides shifting. I see women looking for alternatives. If you’re not there or you’re on the fence, I get it, but keep reading.

What is the COC Really Doing?

Although there are an array of COC’s on the market, they generally contain a combination of progestin (synthetic progesterone) and synthetic oestradiol (E2). These “hormones” (though they’re not really hormones) inhibit ovulation which means the bleed experienced on the COC is not a period at all, it’s simply a withdrawal bleed for which there is no medical requirement. They can also cause other less than desired effects:

1. Nutritional Imbalances

  • B Vitamins: Deficiency of B9 (folate), B12, B6 and to some degree, B2 are recognised as a likely reality of being on the COC. B vitamins are important for energy, neurological function and especially pre-conception.

  • Zinc: Research looking at women on the COC for an average of 18months demonstrated statistically significantly lower levels of zinc when compared to their non-using counterparts. Zinc is important for immune health, thyroid function and skin.

  • Copper: the oestrogen within the COC can lead to dangerously high copper levels. Side effects of which can include mood issues (less pleasure and more agitation) and oxidation.

  • Impacts on selenium, vitamin C, magnesium and vitamin E have also been noted.

2. Disrupted Cortisol Levels

Research has shown that women on the COC have higher than normal total cortisol production and abnormal cortisol production patterns. Most notably a weakened cortisol awakening response (CAR) which ordinarily would provide that ‘get up and go’ in the morning.

3. Blood Clots

All hormonal contraception comes with some risk of blood clotting, though some more than others. Research is suggesting we can use sex hormone binding globulin (SHBG) levels as a measure of risk for blood clotting. This is relevant because one of the biggest drivers for SHBG is oestrogen, which is found in the COC. Higher oestrogen pills such as Estelle and Juliet appear to have a greater effect on SHBG.

4. Digestive Issues and Altered Microbiome

The oestrogen within the COC can influence changes in bile composition which in the long term can lead to gallbladder disease, but in the short term will alter the gut microbiome and lead to increased intestinal permeability (aka leaky gut). This has a whole host of undesired effects which you can learn more about here.

5. 97% Less Progesterone

The pill suppresses progesterone by 97%, not really a surprise when you consider that a female must ovulate in order to produce progesterone. Although the COC contains progestins, these aren’t the same as natural progesterone (see figure 1) and don’t have the same health promoting benefits. Benefits of natural progesterone include: bone health, immune health, nervous system support, thyroid health, hair growth and mood.

Then you have to consider what can happen when you come off the COC, which is namely post pill PCOS and post pill acne. Both can be avoided or treated (if need be), thank fully!

Is the COC Really Working for you?

As I’ve always said, there are two key scenarios in which in the COC might be a requirement:

  • When it’s the only viable form of contraception (eg other forms have been determined more of a risk to the individual).

  • In severe cases of endometriosis when skipping the period is the best means for achieving symptom relief.

In all other instances of COC use, I typically recommend a regular assessment of whether it truly is the best form of contraception. The blood tests below provide a great place to start. They can be ordered via a General Practitioner, however some may incur an out of pocket fee.

  • Sex Hormone Binding Globulin (SHBG): between 40 - 120nmol/L is the goal.

  • Bilirubin: 10 mmol/L is the goal. This measure provides insights to healthy bile composition.

  • Total B12: greater than 400 pool/L is the goal.

  • Zinc: 15 nmol/L is the goal.

  • Copper: levels should be equivalent to, or less than zinc and anything above 20 umol/L is too high.

For anyone considering coming off the COC, here’s a check list to consider:

Step 1: Determine an alternative form of contraception, if that's a requirement. ⁠

Step 2: Speak with a GP about your decision and about having blood testing done, using the above list.

Step 3: Consult with an experienced health professional (Holistic GP, Naturopath or Nutritionist) who can help you in reviewing the blood test results and use your health history to support you in making a healthy transition away from the COC. In same cases you might want to do Step 2 and 3 in reverse order. ⁠

I hope this is helpful. If you need more advice, the Healthy Hormones program could be for you. If you're not sure, please book a complimentary 15-minute consultation.


Stewart M , et al. Combined oral contraceptives. The pharmacology of combined oral contraceptive pills old and new. O&G Magazine. 2014; 16 (2): 14 - 17.

Gaffey AE, Wirth MM, Hoks RM, Jahn AL, Abercrombie HC. Circulating cortisol levels after exogenous cortisol administration are higher in women using hormonal contraceptives: data from two preliminary studies. Stress. 2014;17(4):314-320. doi:10.3109/10253890.2014.919447

Raps M, Helmerhorst F, Fleischer K, et al. Sex hormone-binding globulin as a marker for the thrombotic risk of hormonal contraceptives. J Thromb Haemost. 2012;10(6):992-997. doi:10.1111/j.1538-7836.2012.04720.

Taylor CM, Pritschet L, Olsen RK, et al. Progesterone shapes medial temporal lobe volume across the human menstrual cycle. Neuroimage. 2020;220:117125. doi:10.1016/j.neuroimage.2020.117125.

Figure 1. Comparison of Levonorgestrel (a form of progestin) and progesterone.

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