Modern Contraception – When Will We Leave the Idea of a ‘Normal’ Woman Behind?

By Rose Stevens

In school, whether it is in sex education or in biology, we are taught about the normal woman’s reproductive system. We are taught that the normal woman’s menstrual cycle is around 28 days. We are taught she has regular predictable periods. We are taught that in a normal woman these periods are 5 days in length and start at age 12 or 13. Our doctors and our politicians grow up ascribing to this idea of the normal woman. However what we are never taught is that she does not exist. Calling the reproductive biology of any woman ‘normal’ is misleading when the existent natural variation both is huge and critically under acknowledged in education and medical practice. Ignoring this variation could well be leading to unnecessarily high levels of side effects from hormonal contraception and certainly leading to young girls thinking their bodies’ reactions may be abnormal or dysfunctional. We need to appreciate and account for this diversity when planning sexual health policy and education.

The evidence for women’s reproductive variation is out there. A study called ‘How regular is regular?’ found that women’s shortest and longest menstrual cycles varied by an average of 10.2 days.1 Another study in the UK found that 4.8% of girls start their period before age 11 and 10.1% start it after age 15.4 Variation does not just exist in the menstrual cycle itself but in the underlying reproductive hormones that guide it. Ovarian steroid hormones such as oestrogen and progesterone vary massively between women and between populations across the world. In fact, the average progesterone level of healthy women in some agricultural populations around the world would mean they would be classified as infecund had they been observed in a clinical setting in the United States.7 It is these reproductive hormones that are employed and influenced by hormonal contraception.

FSH hormones over menstrual cycle, showing variability between females

FSH hormone concentrations over the course of the menstrual cycle, showing variability between females and cycles.

Currently contraception is designed and administered, based on the assumption that all women will respond in a similar manner. Globally, policy documents on how to improve family planning services rarely contain any mention of needing to take into consideration physiological variation and most seem to either be unaware of the huge variation out there or ignore it and instead implicitly subscribe to the “normal vs. abnormal” paradigm that steers much medical practice. The default is to view variation as dysfunction3 instead of trying to account for it.

The reason variation makes giving everyone the same contraception problematic is because the aim of hormonal contraceptive design is to provide an effective and safe dose with minimal side effects that still gives a very low chance of pregnancy. Finding this balance will depend on a woman’s individual level of endogenous hormones – the natural concentrations of hormones in her blood. The further off the contraceptive dose is from this balance, the more potential there is for side effects. So as expected, if one dose of contraception is given as the default to all women, side effects will occur in many cases.

Is this just perhaps the small price we pay for convenient easy fertility control? According to both providers and producers of hormonal contraceptives, the side effects are generally considered to be tolerable and not too bad. In a review of the clinical evidence for side effects of the pill, several side effects such as headaches, mood changes and libido changes were dubbed as either clinically insignificant or so rare as to be of minimal importance.2 But the tide has been turning for some time now on the acceptability of these side effects and women have been speaking out about how much suffering they have had to go through.

"uncalculated dosing up on reproductive hormones can cause a lot of problems, not just contraceptive benefits"

It seems these side effects may be far from ‘minor’ or ‘nuisance’ as they are currently referred to in clinical or policy literature. Some side effects, such as depression, have recently started to be taken seriously with the publication of a Danish study that followed over a million women using hormonal contraception. They found that, especially among adolescents, hormonal contraceptive use was associated with subsequent use of antidepressants and a first diagnosis of depression.6 This evidence coincidentally came to light around the same time as a male contraceptive injection trial, also using reproductive hormones, was prematurely halted. This was following the recommendation of an external safety review committee as, despite good efficacy, it caused relatively high frequencies of mild to moderate mood disorders. It seems the wider world is starting to acknowledge what many women have known for a long time; that uncalculated dosing up on reproductive hormones can cause a lot of problems, not just contraceptive benefits.

Indeed hormonal contraception has been one of the most transformative and liberating inventions in the past century, possibly ever. The Economist went as far to dub the contraceptive pill the invention that ‘defined the 20th century.’ It has given women control over their own bodies; their fertility and their sexuality. It has given them the ability to remain in education or employment for as long as they like without fear of becoming pregnant. Globally, it is helping improve individual health, gender equity and family well-being. But right now, the way it is administered and treated in policy is doing women a serious injustice.

contraceptive pills, the pill

Sex education needs to incorporate much more information on the variation that exists in women’s bodies. Therefore if they do experience side effects or react differently to their peers, they would not consider themselves reacting ‘wrongly’ or feel like they were not normal but be more likely to seek something better fitted to them. It also needs to include much more information on the contraceptives on offer.  Currently, UK legislation states that sexual and reproductive education only has to cover HIV, AIDs and STIs. This means adolescents often leave school having little idea as to what is available to them or knowledge that there are lots of different methods and doses they can choose from. They also are very rarely taught about the possible side effects or what to do to go about switching methods and getting help if they have a problem.

This lack of knowledge about their options is exacerbated by the tendency to start all young girls on one of a few default pills as soon as they seek contraception, giving them the standard dose and sending them on their way. They may not be given the full choice of what is on offer and there is no current way of predicting which dose it is best to start a woman off on so that it has the best chance of matching her physiology.

Ideally we need a measure that can be used quickly and easily to predict which dose to give women to minimise side effects whilst still preventing pregnancy. This basic individual dosage choice is used across medicine by all health care workers for so many drugs. It is used right from the choice between taking one or two paracetamol to the precise calculations carried out by anaesthetists. However it is still not done for one of our most common drugs: the hormonal contraceptive. It is obvious that our variation-ignorant one-size-fits-all model of prescribing contraception is not working and we need a new one.

iphone showing fertility cycle on Natural Cycle app

‘Natural Cycles’ app

Some women are now instead choosing not to rely on government services or hormonal contraceptives at all and are taking things into their own hands. Natural fertility trackers that tell you when it is safe to have sex without fear of conception are on the rise. These apps and websites are based on the assumption that variation does exist and they learn from the data you input to take into account natural variation and predict accurately when you are fertile. Recent clinical trials have shown that the number of pregnancies predicted by actual use of app ‘Natural Cycles’ for instance, was lower than actual use for the contraceptive pill.5

All in all, it is clear that finding the right contraception at this time is very difficult for women. There is indeed progress being made and new contraceptives are being developed, including a non-hormonal male injectable contraceptive ‘Vasagel’ so perhaps one day the burden will not be so heavily on women. However in the meantime, if you have experienced some side effects from contraception know that this is normal too. If you have found better ways to bear them or better methods to use, share them with your friends. We do not yet have a way to know what will work best for who, but word of mouth may help get us some way to more women knowing what could be available. If we do not get this kind of education in school and do not get the support we need, it is important that we educate each other and provide that support – at least until the world catches up and realises each person can’t just be fitted into the box of ‘normal’, especially when it comes to contraception.

For more information of the pros and cons of various contraceptives including hormonal methods and fertility trackers see:


rBy Rose Stevens

Rose is a recent graduate of Human Sciences from Wadham college Oxford, who is currently working as a research assistant in the Department of Anthropology. She studies the causes of side effects of hormonal contraceptives and the reasons that women discontinue taking them.


Further Reading

  1. Creinin, M.D., Keverline, S. & Meyn, L.A., 2004. How regular is regular ? An analysis of menstrual cycle regularity. Contraception, 70(4), pp.289–292.
  2. Goldzieher, J.W. & Zamah, N.M., 1995. Oral contraceptive side effects: Where’s the beef? Contraception, 52(6), pp.327–335.
  3. Lipson, S.F., 2001. Metabolism, Maturation, and Ovarian Function. In P. T. Ellison, ed. Reproductive Ecology and Human Evolution. New York: Aldine Transaction, pp. 235–248.
  4. Morris, D. H., Jones, M. E., Schoemaker, M. J., Ashworth, A., & Swerdlow, A. J. (2010). Determinants of age at menarche in the UK: analyses from the Breakthrough Generations Study. British Journal of Cancer, 103(11), 1760–1764.
  5. Scherwitzl, E. B., Danielsson, K.G., Sellberg, J.A., & Scherwitzl, R. Fertility awareness-based mobile application for contraception. The European Journal Of Contraception & Reproductive Health Care  21 , Iss. 3,2016
  6. Skovlund CW, Mørch LS, Kessing LV, Lidegaard Ø. Association of Hormonal Contraception With Depression. JAMA Psychiatry. 2016;73(11):1154-1162. doi:10.1001/jamapsychiatry.2016.2387
  7. Vitzthum, V.J. & Ringheim, K., 2005. Hormonal contraception and physiology: a research-based theory of discontinuation due to side effects. Studies in family planning, 36(1), pp.13–32.

Link to male contraceptive trial article:

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