Walk into almost any doctor’s office as a young woman and there is a good chance the birth control pill will come up at some point. Sometimes you ask for it. Sometimes it is offered as the solution to something else. Acne. Painful periods. Irregular cycles. Heavy bleeding. Mood swings.
For many women the pill becomes a normal part of life. You take it every day and do not think much about it. After all, millions of women use it. It must be safe.
However, when you begin looking at the science behind hormonal contraception and the history of women’s health research, the picture becomes more complicated. The pill is not just a contraceptive. It is a medication that changes the hormonal environment of the body. Hormones influence almost every system in the body. When that system changes, the effects extend far beyond preventing pregnancy.
Women deserve to understand what those effects may be.
The history of women in medical research
For much of modern medical history, women were largely excluded from clinical trials. Researchers believed that hormonal fluctuations during the menstrual cycle would complicate research results. Instead of designing studies that accounted for those differences, women were frequently left out of the research altogether.
This practice changed in 1993 when the United States passed the NIH Revitalization Act, which required women to be included in federally funded clinical trials.
Before that point, many medications had been studied primarily in men even though they were later prescribed to women. Male physiology was often treated as the default model for human biology.
Research has since shown that men and women metabolise drugs differently. A review published in the British Journal of Clinical Pharmacology found that women are significantly more likely than men to experience adverse drug reactions. Some analyses suggest women may be between 50 and 75 percent more likely to experience side effects from medications.
These findings highlight the long-standing gap in research that specifically examined how medications affect female physiology.
The development of the birth control pill
The first oral contraceptive pill was approved in 1960. It changed reproductive health and family planning in profound ways. For the first time, women had a reliable pharmaceutical method of preventing pregnancy.
The development of the pill also reflects the ethical standards of medical research at the time.
Large contraceptive trials were conducted in Puerto Rico in the 1950s. Many participants were poor women with limited access to healthcare and education. Historical accounts suggest that some participants were not fully informed that they were participating in an experimental drug trial.
The doses used in the early formulations of the pill were also much higher than those prescribed today. Many women reported severe side effects including nausea, headaches, and blood clots. Three participants died during the trials, although investigators did not determine a confirmed causal link to the drug.
Historians frequently reference these trials when discussing the evolution of modern clinical research ethics.
Cancer risk and hormonal contraception
One of the lesser known facts about hormonal birth control involves its classification by international cancer authorities.
The International Agency for Research on Cancer, which operates under the World Health Organization, classifies combined estrogen-progestogen oral contraceptives as a Group 1 carcinogen. This classification means there is sufficient evidence that the substance can cause cancer in humans.
Group 1 does not mean every person exposed will develop cancer. It means scientific evidence has established a causal relationship in certain contexts.
Studies have shown an increased risk of breast cancer, cervical cancer, and liver cancer among users of combined hormonal contraceptives.
The point here is not to create fear. The point is that medications affecting hormones come with biological trade-offs, and women deserve to understand those trade-offs and make informed decisions.
Hormones affect far more than reproduction
Hormones influence much more than fertility. They play a role in mood, metabolism, appetite, immune function, and behaviour.
Hormonal contraception works primarily by suppressing ovulation and altering the body’s natural hormonal cycle. This suppression can have broader effects that researchers are still studying.
Some research suggests hormonal contraception may influence patterns of attraction and mate preference. Studies published in Psychoneuroendocrinology found that women using oral contraceptives showed reduced preference for highly masculine male faces compared with women experiencing natural hormonal cycles.
Other studies examining couples found that women who met their partners while using hormonal contraception tended to have partners rated as less facially masculine than women who were not using hormonal contraception at the time.
The effects observed in these studies appear relatively small and findings are not entirely consistent across all research. The broader takeaway is that hormonal changes can influence behaviour and perception in ways scientists are still exploring.
Hormonal contraception and mental health
Mood changes are another area frequently discussed by women who use hormonal contraception. Some women report feeling no difference. Others notice changes in mood, anxiety levels, or emotional regulation after starting hormonal birth control.
A large Danish cohort study involving more than one million women found that hormonal contraceptive users had higher rates of antidepressant use compared with women who were not using hormonal contraception.
The association was strongest among adolescents. Researchers noted that the findings showed correlation rather than proof of direct causation. Even so, the study suggests hormonal changes may influence brain chemistry and mental health in some individuals.
Nutrient depletion and hormonal contraception
Hormonal contraceptives can also affect nutrient levels in the body. Several studies have found associations between oral contraceptive use and lower levels of nutrients such as vitamin B6, vitamin B12, folate, magnesium, and zinc.
These nutrients play important roles in energy metabolism, nervous system function, immune health, and mood regulation.
Nutrient depletion does not occur in every woman using hormonal contraception. It does highlight the importance of diet quality and nutrient intake for women who use these medications long term.
Hormonal contraception and metabolic health
Hormones also influence how the body regulates blood sugar, insulin, and fat storage. Some studies suggest hormonal contraceptives may affect insulin sensitivity and glucose metabolism in certain women.
This becomes particularly relevant for women with underlying metabolic conditions such as polycystic ovary syndrome, insulin resistance, or obesity.
PCOS itself is estimated to affect up to 10 percent of women of reproductive age worldwide. Hormonal contraceptives are commonly prescribed to manage PCOS symptoms such as irregular cycles and acne. However, they do not address the underlying metabolic drivers of the condition.
Lifestyle factors such as diet, physical activity, and metabolic health play a major role in managing these conditions.
Contraception in South Africa
Contraceptive use is widespread in South Africa. According to the South African Demographic and Health Survey, approximately 55 to 60 percent of women use some form of contraception.
The most commonly used method in South Africa is injectable contraception rather than the pill.
Despite widespread access to contraceptives, unintended pregnancy remains common. Studies suggest that more than half of pregnancies in South Africa are classified as unintended.
This highlights the importance of better education and support around reproductive health.
The bigger picture
Hormonal birth control has had a profound impact on reproductive autonomy. It has allowed women to plan pregnancies and make decisions about family life in ways that were previously impossible.
At the same time, it is still a medication that alters a complex hormonal system.
Women deserve honest conversations about how that system works and how medications may influence it.
Understanding your body, asking questions, and learning about the potential effects of medications is not controversial. It is part of taking responsibility for your health.
Informed decisions begin with information. Women should have access to that information so they can choose what is right for their own bodies and their own lives.
I’d love to hear what you think. Did this article give you new insight into hormonal birth control and women’s health? Leave a comment below to share your thoughts or experiences. If you found this information useful, consider sharing it with a friend who might benefit from knowing the facts too. Let’s keep the conversation going and help more women make informed decisions about their health.
If you’re interested in learning more about period products and how they affect your health, check out my other post here.
[…] If you found this helpful and want to understand how everyday products can affect your hormones, you can read my full article on endocrine disrupting chemicals in period products here. […]