GLP-1s & Fertility: The "Ozempic Baby" Research

The "Ozempic Baby" Phenomenon

Social media is full of stories: Women who struggled with infertility for years suddenly becoming pregnant after starting Ozempic, Wegovy, or Mounjaro. The hashtag #OzempicBaby has exploded. Fertility clinics are reporting unexpected pregnancies. Even women on birth control are finding themselves pregnant.

But is this a real pharmacological effect, or are we seeing the predictable result of weight loss improving fertility in women with obesity?

The truth, as we'll explore, is nuanced. GLP-1 medications can absolutely improve fertility—but the mechanism is largely through their effects on body weight and insulin resistance, particularly in women with polycystic ovary syndrome (PCOS).

What the Research Actually Shows

The most comprehensive data comes from a 2023 meta-analysis published in BMC Endocrine Disorders that pooled data from 11 randomized controlled trials involving 840 women with PCOS.

Key Findings from the Meta-Analysis

• Natural pregnancy rate: 72% higher in GLP-1 group vs. control
• Menstrual regularity: Significantly improved (though high heterogeneity between studies)
• IVF pregnancy rate: No significant difference (likely depends on other factors)
• Hormonal improvements: Reduced total testosterone, increased sex hormone-binding globulin (SHBG)

Importantly, the benefits were seen primarily with natural pregnancy rates, not IVF outcomes—suggesting the mechanism involves restoring normal ovulation rather than improving egg quality.

The Exenatide Study

One particularly striking study involved 176 overweight women with PCOS who received either exenatide (an older GLP-1) or metformin for 12 weeks. After switching to metformin alone for the following 12 weeks, researchers found:

This suggests that GLP-1 pre-treatment may "prime" the reproductive system for pregnancy, potentially through metabolic improvements that persist even after stopping the medication.

Why Does This Happen?

The fertility improvements from GLP-1 medications appear to work through several interconnected pathways:

The PCOS Connection

PCOS affects 4-21% of reproductive-age women and is the leading cause of anovulatory infertility. The condition is characterized by:

• Irregular or absent menstrual cycles
• Elevated testosterone levels
• Insulin resistance (present in 70-80% of cases)
• Overweight or obesity (in 60-70% of cases)

GLP-1 medications address multiple aspects of PCOS simultaneously: they cause weight loss, improve insulin sensitivity, and reduce testosterone levels. This makes them particularly effective for restoring fertility in this population—though they're not officially approved for PCOS or infertility treatment.

What About Birth Control?

Because GLP-1 medications slow gastric emptying, there's been concern that they might reduce absorption of oral contraceptives, leading to unintended pregnancies.

The research here is actually reassuring—for semaglutide:

However, the story is different for tirzepatide (Mounjaro/Zepbound):

The Mounjaro prescribing information specifically recommends that people "switch to a non-oral contraceptive method, or add a barrier method of contraception for four weeks after initiation and four weeks after each dose escalation."

GLP-1s During Pregnancy: What We Know

GLP-1 medications are not recommended during pregnancy. Here's why:

Animal Studies Show Concern

• Fetal growth restriction observed in rats, rabbits, and monkeys
• Increased pregnancy loss at doses below human equivalent
• Skeletal abnormalities in some animal models
• Medications can pass into breast milk

Human Data Is Reassuring (But Limited)

A 2023 observational study examined outcomes among more than 50,000 pregnant women with Type 2 diabetes. Among the 900+ women who were taking GLP-1 RAs when they discovered their pregnancy:

However, this data has important limitations: small sample size, lack of long-term follow-up, and potential confounding by the underlying conditions that led to GLP-1 use.

Current Recommendations

• Before conception: Stop GLP-1 medications at least 2 months before trying to conceive (due to long half-life)
• If pregnant while taking GLP-1: Stop immediately and contact your healthcare provider
• Breastfeeding: Not recommended due to potential transfer to breast milk

Both Novo Nordisk (Wegovy) and Eli Lilly (Zepbound) have established pregnancy registries to track outcomes in women who took these medications during pregnancy.

The Research Gap

Despite the buzz, there's a striking lack of research on several key questions:

Dr. Melanie Cree at the University of Colorado is currently running an NIH-funded clinical trial specifically examining fertility outcomes in young women with PCOS taking semaglutide. Results aren't expected for several years.

What This Means For You

If You're Trying to Get Pregnant

• GLP-1s are not approved fertility treatments and should not be used specifically for this purpose
• If you have PCOS and obesity, weight loss (by any method) improves fertility
• Discuss with your doctor before conception—they'll want you to stop 2 months before trying
• Consider that the fertility benefits may persist after stopping the medication

If You're NOT Trying to Get Pregnant

• Take contraception seriously, even if you've had fertility issues before
• Semaglutide (Ozempic, Wegovy) doesn't appear to affect birth control effectiveness
• Tirzepatide (Mounjaro, Zepbound) may reduce oral contraceptive effectiveness—use backup methods
• Non-oral contraceptives (IUD, implant, patch) are unaffected by GLP-1 medications
• If you've been "accidentally" relying on PCOS-related infertility, that may no longer apply

If You Become Pregnant While on GLP-1s

• Stop the medication immediately (unless you have diabetes—consult doctor first)
• Contact your healthcare provider right away
• Don't panic—current evidence doesn't suggest major harm from early exposure
• Continue prenatal vitamins and standard prenatal care
• Consider enrolling in manufacturer pregnancy registries to contribute to research