She was 16 when a doctor prescribed the birth control pill. The conversation was brief and covered blood clots and what to do after a missed dose. She took the pill faithfully for the next 15 years, through college, medical school, and residency. By age 31, her body was sending signals that confused her: puffiness and inflammation she could not explain, vaginal dryness that made sex less comfortable and that lubricant didn’t seem to fix, and less desire than before. By then she was a gynecologist, and she still didn’t connect the dots between the pill she swallowed every morning and what it was doing to her body.
That patient was me. I started the pill at 16 and stopped at 31, and only later did I understand it had been driving my inflammation, vaginal dryness, and low libido.
I trained at Harvard and MIT, completed OB/GYN residency at the University of California at San Francisco, and passed my boards, and no one ever taught me to prescribe the pill with the full informed consent women need. While I was learning to write those prescriptions, my own body was sending the signals I would later teach myself to ask my patients about. At the time, I brushed them off and blamed long hours, stress, and the ordinary wear and tear of a demanding career.
Only after I stopped the pill did the pattern come into focus. Once I was off it, I could see what it had been doing, and I went looking for the research I had never been taught. That was when I understood that women deserve a far better consent conversation than the one I received as a patient or even the one I was trained to give as a doctor.
For three decades now, I have prescribed the pill, though I rarely prescribe it now. I wrote those prescriptions for teenagers whose cramps sent them home from school, for women building careers before families, for women bleeding through their clothes, and for women whose painful periods, sometimes from endometriosis, had taken over their lives. The pill did what I promised. What I did not always do was tell them the rest: the parts no one taught me. I am making up for that now, starting here.
Most women get one sentence about risk. Then the prescription renews, year after year, sometimes for decades, without a second conversation. Few women hear that the pill changes how the liver makes proteins, lowers the testosterone their tissues can use, disguises the lab values their doctors will later rely on, can thin and dry vaginal tissue, and carries a breast cancer risk that rises with the age of the woman taking it.
The pill arrived in 1960 as one of the great liberation technologies of the twentieth century. It gave women authority over when, and whether, they became mothers, and it rewrote who could finish school, build a career, and plan a life. More than sixty years later, the revolution has stalled at the consent conversation. Mainstream medicine handed women control of their fertility and kept the full story of their bodies to itself.
The pill is also one of the most protective medicines I prescribe. Five years of use lowers ovarian cancer risk by about 20 percent, and the protection lasts more than 30 years after stopping [1]. Full informed consent includes that too. It includes all of it.
My own specialty defines informed consent as a conversation about a treatment’s nature, risks, benefits, and alternatives, shaped by the patient’s own values [2]. Hold the typical pill visit up to that standard and it fails. The script covers clots, smoking, and missed pills, but it rarely touches SHBG, free testosterone, vaginal tissue, the labs the pill distorts, the age-dependent breast cancer numbers, or which progestin a woman was given and why.
The knowledge gap appears wherever researchers look for it. In a 2024 survey of 817 women in Lebanon, nearly half of those asked said they had never been told about the pill’s benefits, and nearly half said they had never been told about its risks [3]. The average score on a 25-point test of pill knowledge was 5.7 [3]. Women want this conversation, and they are not getting it.
Desire is where the silence costs the most. In a community survey of nearly 500 pill users in Saudi Arabia, seven in ten reported at least one side effect, and about a third of those women named decreased libido [4]. When researchers analyzed German YouTube videos in which 158 women told their own pill histories, mood swings and depressed mood were among the most common effects they described, and 87 of the 91 who rated the experience of stopping called it positive [5]. These women learned the pill’s effects from their own bodies. The pattern matches what I have heard in my office for thirty years.
I am indicting a system, and I was part of it. The failure is structural: a fifteen-minute visit, a refill that renews without a new conversation, a package insert few women read, and a training culture that treats the pill as the most neutral drug in the formulary. Individual clinicians inherit that structure, and women pay for it in their tissue, their desire, and their lab results.
I believe informed consent for the pill should be as specific as informed consent for surgery. In my humble gynecological opinion, a drug a woman may take for twenty years deserves at least the conversation we give a two-hour operation. Here is that conversation, system by system.
An endocrinopathy is any disorder caused by abnormal hormone production, transport, or signaling. Too much of a hormone qualifies, and so does too little. So does a hormone trapped on the wrong carrier protein, or a receptor that stops receiving the message.
By that definition, the combined pill produces a predictable endocrinopathy across several axes at once. It suppresses the hypothalamic-pituitary-ovarian axis, lowering the brain’s signals to the ovaries and, with them, the body’s own estradiol and progesterone [6]. It suppresses ovarian and adrenal androgen production [7]. It drives the liver to make more binding proteins for sex hormones, thyroid hormone, and cortisol [8]. It shifts thyroid physiology enough to change how a woman on thyroid medication must be dosed [9].
I believe the pill is the most common endocrinopathy in women, and that most women taking it have no idea they are living with one. No epidemiologic study has formally ranked it, so I offer this as clinical judgment built on two facts: how many women take the pill, and how reliably it moves their hormones. The argument does not require the pill to be dangerous. It requires only that women be told.
On a combined pill, you do not ovulate. The estrogen and progestin in each active tablet tell your brain that the ovaries have already done their work, so the brain stops sending the signal to release an egg. The bleeding that arrives in the placebo week is a withdrawal bleed, triggered by the drop in synthetic hormones.
Many women I meet in their late thirties have not had a natural menstrual cycle since high school. They know their pill pack better than their own rhythm. When they stop, they meet a body they have never met as adults, with its real cycle length, its real skin, its real mood, and its real desire.
Ethinyl estradiol, the estrogen in most combined pills, passes through the liver first. The liver answers by making more of several carrier proteins. A 2024 review of 91 laboratory tests in contraceptive users found that sex hormone-binding globulin (SHBG) rises by roughly 200 percent, cortisol-binding globulin by about 100 percent, and thyroid-binding globulin by about 90 percent [8].
Think of SHBG as a sponge for testosterone. Bound testosterone circulates, but your tissues cannot use it. A meta-analysis of 42 studies found that combined pills cut free testosterone, the fraction your tissues can use, by about 61 percent [7]. That drop appeared regardless of estrogen dose or progestin type, while the rise in SHBG was smaller with lower-dose pills and older, second-generation progestins [7].
In 2006, a sexual medicine team measured SHBG in 124 women with sexual complaints. Current pill users carried about four times the SHBG of women who had never taken the pill, and women who had stopped still carried roughly twice the never-users’ level more than four months after the last tablet [10]. The study was retrospective and drawn from a clinic population, so it describes women who were already struggling. For those women, stopping the pill did not immediately return what the pill had taken.
If you take the pill, several routine labs are reporting on the pill as much as on you. Some look worse than your body is, and some look better.
High-sensitivity C-reactive protein is the inflammation marker many doctors use to refine cardiovascular risk. In female athletes, pill users had markedly higher hsCRP than non-users, while haptoglobin, another inflammation protein made by the liver, stayed flat [11]. A 2025 analysis of U.S. national survey data found CRP ran higher in pill users no matter how much they exercised or how well they ate [12].
Researchers disagree about what the rise means. One reading holds that oral estrogen simply prompts the liver to make more CRP, while the authors of the 2025 analysis concluded it reflects true systemic inflammation [12]. In the Nurses’ Health Studies, CRP rose about 10 percent for every five years of pill use, a pattern the authors read as a sign that long use may raise generalized inflammation [13]. On either reading, an hsCRP drawn on the pill cannot be interpreted the way it would be off the pill. I learned this in my own blood before I ever taught it.
The binding-protein rise lifts total thyroxine on paper and can change how much thyroid hormone a woman needs [8][9]. In a 2025 study of 1,001 women in Qatar who had used estrogen-containing pills, those whose SHBG ran above the 99th percentile had about ten times the odds of hypothyroidism [14]. Only 34 women in that study had hypothyroidism, so the estimate is imprecise, and it points in a direction worth watching. A woman on levothyroxine who starts or stops an estrogen-containing pill needs her dose rechecked.
A woman told her morning cortisol is high may be looking at extra cortisol-binding globulin. A woman told her total testosterone is normal may still have very little free testosterone to use. It’s important that each result is interpreted with your birth control pill in mind.
Four systems in, and none of this appears in the consent most women receive. The rest of the list is where women feel the pill most: in the vagina, the pelvic floor, the brain, and the breasts.
Below the line is the rest of the inventory: what the pill does to vaginal tissue and genital arousal, how it can teach the pelvic floor to brace against pain, what the best randomized trial shows about desire, the depression data, the bone story that changes by decade, clots, heart attack, stroke, and the migraine question every woman should be asked, blood pressure and blood sugar, the liver and the gut, the full breast cancer numbers by age and by progestin, the nutrient depletions, and the cancers the pill prevents. Each is part of the consent you should have received.
I took the pill for 15 years and prescribed it for 30. I owe my patients, my 16-year-old self, and you the version of this conversation none of us got.
If you are 35 or older and still on the pill, the breast cancer section applies to you more than it did at 25. Your absolute risk moved with your age, and few prescribers know about the best evidence linking the birth control pill to a modestly increased risk of breast cancer, according to the New England Journal of Medicine.
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