‘Ozempic changed my life’: Do diabetes vaccines increase the chance of pregnancy?

Iathryn began taking Ozempic “off label” in April 2023 at the advice of her doctor. The Illinois native had been diagnosed with gestational diabetes during her pregnancy and struggled with her weight after the birth of her daughter. After briefly taking a break from the drug in July due to side effects, she began taking it again in August. In September, she found out she was pregnant.

Although Kathryn wasn’t using birth control, the pregnancy still came as a surprise. Doctors had told her it was unlikely she would conceive naturally, and she had undergone multiple failed rounds of intrauterine insemination (IUI) before giving birth to her first child through IVF. “It was completely unexpected,” Kathryn tells me. “We hadn’t really planned on expanding our family so quickly—my first daughter was only 13 months old.”

Ozempic is a type 2 diabetes medication, not a fertility treatment. But stories like Kathryn’s are not uncommon. In fact, there is a whole register dedicated to monitoring women who have become pregnant while taking Wegovy, a weight-loss drug that contains the same active ingredient as Ozempic. Other women share their stories on X using the hashtag #OzempicBabies.

The weight loss caused by this class of drugs is likely to be the cause of these unexpected pregnancies, says Adam Balen, a consultant in reproductive medicine at Leeds Teaching Hospitals. Extra weight negatively impacts women’s fertility in a number of ways, including inhibiting ovulation and reducing the quality of their eggs and womb lining, he explains. So when overweight or obese women lose weight, their chances of getting pregnant often improve.

But there’s another theory that drugs like Ozempic could interfere with the effectiveness of birth control pills. These new diabetes and weight-loss drugs mimic a natural gut hormone called GLP-1, which has three main functions: stimulating insulin, slowing stomach emptying, and acting on parts of the brain that regulate hunger. It’s the second function that can interfere with the body’s absorption of oral contraceptives, potentially leading to unexpected pregnancies.

A major pharmaceutical company, Eli Lilly, advises women to switch to non-oral contraceptives or a barrier method when starting their medications Mounjaro or Zepbound, or when moving to a higher dose. Both Mounjaro and Zepbound contain the GLP-1 agonist tirzepatide.

However, there is no evidence that this theory applies to Ozempic and Wegovy, which are made by Novo Nordisk and contain a different compound called semaglutide. A Novo spokesperson said its drugs did not alter overall exposure to the active ingredients in the combination pill “to a clinically relevant extent” in the company’s clinical trials.

“The whole issue of the birth control pill is still a little bit uncertain in terms of how much it affects these pregnancies,” Balen says. The absorption factor could have some influence, but weight loss is probably the biggest factor, he adds.

This phenomenon has led some researchers to speculate that GLP-1 drugs could improve fertility in relation to the most common cause of anovulation in women: polycystic ovary syndrome (PCOS). The condition affects about one in 10 women and symptoms include irregular periods, excess body hair and weight gain. It was one of the reasons Kathryn had trouble conceiving her first child.

PCOS patients are often prescribed the contraceptive pill to regulate their periods, but this does not address the underlying mechanisms of the condition and it certainly does not improve fertility.

Melanie Cree, director of the University of Colorado Multidisciplinary PCOS Clinic, is the principal investigator of a clinical trial testing semaglutide in 80 obese girls and women with PCOS, aged 12 to 35. She explains how GLP-1 drugs are thought to stimulate ovulation in this condition.

In about 80 percent of people with PCOS, the finely tuned system of hormone secretions needed for ovulation is out of sync, Cree says. This hormonal imbalance is driven by two mechanisms: problems with the brain’s hypothalamus and insulin resistance. The latter occurs when the body’s cells don’t respond properly to the hormone that regulates blood sugar.

Insulin resistance can improve when patients lose weight, which is why women with PCOS are often advised to do so at diagnosis. The idea is that the weight loss induced by GLP-1 drugs can improve insulin sensitivity and thus restore the proper hormonal balance for egg release.

There may be another mechanism at play, too, Cree says. In pilot MRI studies, her team noted changes in brain connectivity in women with PCOS who took semaglutide. “The part of the brain that senses calories, the hypothalamus, was better connected to the parts of the brain that make decisions,” she tells me. “We don’t really know neurologically what that is — is it just about appetite, or is there more to it?”

For the most part, though, weight loss appears to be the primary driver, Cree says. Based on her previous research on the syndrome, she says semaglutide is unlikely to have an effect on patients who are at an ideal weight. While 80 percent of women with PCOS have BMIs above normal or high, the rest present with what’s known as a lean phenotype, according to research published in the Journal of Diabetes and Metabolic Disorders.

This raises the question: Do GLP-1 drugs have a special effect on women with PCOS that they generally do not have on women who are overweight or obese?

There is likely to be a greater effect on insulin levels in women with PCOS than in overweight or obese women who do not have PCOS, says Colin Duncan, a lead researcher at the MRC Centre for Reproductive Health at the University of Edinburgh, who is not involved in the Colorado trial. The improvement in fertility could therefore be more dramatic in women with PCOS, he says.

Additionally, PCOS patients may benefit more from a drug-based approach to weight loss, since they have metabolic issues that make it harder to shed pounds. In a process known as postprandial thermogenesis, a woman with PCOS burns about 75 percent of the calories that a healthy woman of the same weight burns after eating a meal, Duncan says.

“That means[women with PCOS]have to exercise, say, 20 percent more every day or eat 4 percent less to be the same as everyone else,” he says. “I think it can be very discouraging for women who are struggling with their weight, so having something that helps to kick-start weight loss alongside lifestyle changes, from a psychological and wellness standpoint, might better enable people to maintain weight loss,” Balen says.

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AFua, who lives in the UK, also struggled with her weight and fertility. She conceived her first son a year and a half after working with PCOS-specific nutritionists to optimise her diet to help her ovulate. Although she didn’t lose any weight, she did manage to conceive naturally in 2020. “I found out on my birthday – it was a good present,” she says.

Two years later, Afua began taking Ozempic on the recommendation of her private endocrinologist and lost 30 kg in less than nine months “like it was nothing.” When she was ready for another child, Afua stopped taking the drug and was pregnant with her second son four months later. “Ozempic has completely changed my life,” she says.

The problem is that GLP-1 drugs are not recommended for women who want to become pregnant because of concerns about safety and the chance of abnormal development of the baby, Balen said.

The U.S. Food and Drug Administration advises women to stop taking Ozempic at least two months before a planned pregnancy. Kathryn, who became pregnant while taking Ozempic, was advised to stop immediately – her second daughter is healthy.

But even when used correctly, access to GLP-1 drugs remains a challenge.

Novo recently restocked its supply of Ozempic and Wegovy after several years of intermittent shortages in the U.S. More importantly, these drugs are only approved for a handful of conditions, and PCOS isn’t one of them.

The UK National Institute for Health and Care Excellence recommends Ozempic for patients with uncontrolled type 2 diabetes who have a BMI of 35 or more and another weight-related health problem, such as high blood pressure. It can also be given to people with a lower BMI if they cannot use insulin because of the risk of low blood sugar.

But GLP-1 drugmakers are working to unlock new indications for their drugs in other weight-related conditions. In July, Britain’s Medicines and Healthcare products Regulatory Agency approved Wegovy to reduce the risk of serious heart problems or strokes in overweight and obese people.

“It would be nice to think that PCOS could be one of those things, along with obesity, that would allow access to these drugs,” Duncan says.

Meanwhile, the syndrome is taking its toll on health care spending. article published in July in the Journal of Clinical Endocrinology & Metabolism by researchers from Cardiff University, more people are being diagnosed with PCOS. They estimate that the cost of treating the condition in the UK was more than £1.2 billion in 2019.

For Afua, Ozempic is a no-brainer. “Even my partner said to me, as soon as you’re done breastfeeding, when you’re ready, we’ll put you back on Ozempic, because he could just see how much of a smile the benefits put on my face,” she says. “I think doctors, the NHS, everyone, just needs to be more aware of what’s out there and what can really help.”