We know some things, we suspect others, and there is much we simply do not know.
At Brazil's 63rd Congress of Gynecology and Obstetrics, physicians confronted a tension as old as medicine itself: a treatment that arrives before its full consequences are understood. GLP-1 agonists — now prescribed by the millions for weight loss — offer genuine benefits to women, restoring fertility and protecting the heart, yet leave critical questions unanswered at the precise moments women need answers most. The gap between what these drugs can do and what science has confirmed is not merely academic; it shapes the reproductive choices and daily lives of women taking them right now.
- GLP-1 drugs are being prescribed to millions of women while pregnancy safety data remains entirely absent, creating a clinical void at one of life's most consequential crossroads.
- The medications interfere with oral contraceptive absorption, meaning women who rely on birth control pills while taking them may be unknowingly unprotected.
- For women with obesity, the benefits are real — restored ovulatory cycles, reduced cardiovascular risk, improved sleep — but side effects like nausea and vomiting can compound existing struggles with food and body image.
- Physicians at the conference are urging a multifactorial approach: medication alone is not a cure, and muscle preservation, nutrition, and exercise remain non-negotiable alongside the drug.
- The medical literature is actively catching up to a prescription reality already in motion, leaving women and their doctors navigating uncertainty in real time.
Late in May, at Brazil's 63rd Congress of Gynecology and Obstetrics, endocrinologist Dr. Clayton Macedo of the Federal University of São Paulo addressed a question growing harder to avoid: what do GLP-1 agonists — semaglutide, tirzepatida, and their class — actually mean for women's health, and where does the evidence run out?
The drugs work by slowing stomach emptying, stimulating insulin secretion, and suppressing appetite at the brain. For women with obesity, the effects can be transformative: ovulatory cycles restored, cardiovascular risk reduced, sleep improved. Women, the data suggests, respond to these medications even more readily than men do. For those whose fertility and organ health have been eroded by excess weight, that matters enormously.
But the clarity stops there. The medications must be discontinued four to eight weeks before conception, and there is no safety data whatsoever for use during pregnancy. Equally pressing, GLP-1 drugs reduce the absorption of oral contraceptives — meaning a woman cannot rely on the pill alone while taking them. These are not footnotes. They are the difference between informed reproductive planning and an unintended gap in care.
Macedo also raised the intersection with eating disorders, which are more prevalent in women — a consideration that cannot be ignored when prescribing appetite suppressants. Side effects across the drug class are consistent: nausea, diarrhea, constipation, vomiting. For some women these are manageable; for others, they deepen existing difficulties with food and body.
The conference was clear that medication is only one part of the picture. Exercise, balanced nutrition, and the preservation of muscle mass remain essential — a woman on a GLP-1 agonist is managing a chronic disease, not escaping it. As prescriptions multiply faster than research can follow, the honest acknowledgment from clinicians is this: we know some things, we suspect others, and there is much we simply do not yet know. For women living inside that uncertainty, it carries a weight of its own.
At Brazil's 63rd Congress of Gynecology and Obstetrics in late May, an endocrinologist from the Federal University of São Paulo took the stage to address a question that is becoming harder to ignore in women's health: what happens when you give a woman a GLP-1 agonist—one of the drugs now prescribed by the millions for weight loss—and she wants to have a baby?
Dr. Clayton Macedo's presentation cut to the heart of a medical reality that has outpaced the evidence. These drugs—semaglutide, tirzepatida, and others in their class—work by slowing stomach emptying, boosting insulin secretion, and suppressing appetite at the level of the brain. They are effective. Women, the data suggests, lose weight more readily on them than men do. And for women struggling with obesity, which damages fertility and strains the heart and organs, that weight loss can restore ovulatory cycles and reduce the risk of cardiovascular disease. Sleep improves. Acid reflux quiets. The reproductive system, starved of function by excess weight, sometimes wakes up again.
But here is where the clarity ends. The medications must be stopped four to eight weeks before a woman tries to conceive. There is no safety data—none—about what happens if she stays on them during pregnancy. The drugs also interfere with how the body absorbs oral contraceptives, meaning a woman taking a GLP-1 agonist cannot rely on birth control pills alone. She needs a backup method. These are not minor details. They are the difference between a woman being able to plan her life and being caught in a gap between what the drug can do and what doctors actually know.
Macedo emphasized that obesity itself is a chronic, progressive disease with real consequences for women's bodies and fertility. Eating disorders, too, are more common in women than men—a fact that matters when prescribing appetite suppressants. The side effects of GLP-1 drugs are consistent across the class: nausea, diarrhea, constipation, vomiting. For some women, these are tolerable. For others, they compound existing struggles with food and body.
The conference highlighted what Macedo called the need for multifactorial management. The drug alone is not the answer. Regular exercise, balanced nutrition, preservation of muscle mass—these remain essential. A woman on a GLP-1 agonist is not cured of obesity; she is managing it, with pharmaceutical help, in the context of a life that must also include movement, food, and the maintenance of her own strength.
The evidence gaps are real and they are widening as prescriptions multiply. Women are taking these drugs now. They are becoming pregnant now. They are experiencing side effects now. And the medical literature is still catching up, still trying to answer questions that should have been asked before the drugs became so common. The conference acknowledged this honestly: we know some things, we suspect others, and there is much we simply do not know. For a woman trying to navigate her own health, that uncertainty is its own kind of weight.
Notable Quotes
Obesity is a chronic, progressive disease with impact on fertility and risks of injury to female target organs— Dr. Clayton Macedo, Federal University of São Paulo
Comprehensive management requires multifactorial approach combining medication with lifestyle changes, regular exercise, balanced nutrition, and muscle mass preservation— Dr. Clayton Macedo
The Hearth Conversation Another angle on the story
Why does it matter that women lose weight more easily on these drugs than men do?
Because it suggests the drugs work differently in female bodies—maybe through hormonal pathways, maybe through how women's brains regulate appetite. If we don't understand why, we can't predict what else might be different. Pregnancy outcomes, for instance.
You mentioned eating disorders are more common in women. Are doctors worried about prescribing appetite suppressants to women with that history?
They should be. The source doesn't say explicitly, but the implication is there—these drugs suppress appetite at the brain level. For a woman with a history of restricting food, that's a different kind of danger than nausea.
Four to eight weeks before pregnancy. Why that window?
The drug needs to clear the system. But honestly, that timeline is probably a guess based on how long the medication stays in your body, not on actual pregnancy studies. They're being cautious because they have no data.
And oral contraceptives don't work properly on these drugs?
The medication slows stomach emptying and changes how the gut absorbs things. Birth control pills need consistent absorption to work. So a woman on a GLP-1 drug could take her pill faithfully and still get pregnant because the drug is interfering with how her body processes it.
That seems like a massive gap in the prescribing information.
It is. And it's the kind of gap that only gets filled when enough women have problems—when the real-world data catches up to the prescriptions already written.
What does multifactorial management actually mean in practice?
It means the drug is not a substitute for living differently. You still have to move your body, eat real food, build muscle. The drug helps, but it's not magic. It's a tool in a much larger toolkit.