Weight loss drugs like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) have transformed obesity care — and increasingly, conversations in fertility clinics. Reports of unexpected “Ozempic babies,” combined with new studies on polycystic ovary syndrome (PCOS) and male reproductive hormones, have raised a serious question: can GLP-1 receptor agonists actually improve fertility?
Research suggests the answer is nuanced. For many people with obesity-related infertility, GLP-1 drugs may indirectly improve reproductive outcomes. But the same medications carry pregnancy-related risks that demand careful planning before conception.
Why Obesity and Fertility Are Tightly Linked
Excess body weight disrupts reproductive function in both sexes. In women, obesity is the most common cause of anovulatory infertility, largely through insulin resistance, elevated androgens, and inflammation that interfere with normal ovulation, according to a 2023 review in Reproductive Biology and Endocrinology.
In men, obesity is associated with lower testosterone, reduced sperm concentration, and increased DNA fragmentation in sperm. The American Society for Reproductive Medicine notes that even modest weight loss — roughly 5% to 10% of body weight — can restore ovulation and improve sperm parameters.
That is the foundation for the GLP-1 fertility story. These drugs produce average weight loss of around 15% (semaglutide) to more than 20% (tirzepatide) in clinical trials, far beyond what lifestyle changes alone typically achieve.
GLP-1 Drugs and PCOS
Polycystic ovary syndrome affects roughly 1 in 10 women of reproductive age and is the leading cause of female infertility. The condition involves insulin resistance, weight gain, irregular cycles, and elevated androgens — all of which GLP-1 drugs can influence.
A 2024 meta-analysis in the Journal of Clinical Endocrinology & Metabolism pooled data from randomized trials of GLP-1 receptor agonists in women with PCOS and overweight or obesity. The drugs significantly reduced body weight, fasting insulin, and total testosterone, and improved menstrual regularity compared with metformin or placebo.
Smaller studies have reported improved ovulation rates and spontaneous pregnancies during or shortly after GLP-1 treatment. A 2023 trial in Fertility and Sterility found that women with PCOS treated with liraglutide alongside lifestyle counseling had a higher rate of natural pregnancy in the year after treatment than those on lifestyle changes alone, though the trial was small and findings need larger replication.
Importantly, the Endocrine Society’s 2023 clinical practice guideline on obesity in PCOS notes that GLP-1 receptor agonists can be considered for weight management in PCOS but stresses they are not approved as fertility treatments and should not be used during pregnancy.
Effects on Male Fertility
Male fertility research on GLP-1s is earlier and smaller, but trends are encouraging. Men with obesity and functional hypogonadism — low testosterone not caused by primary testicular disease — often see hormone levels improve when they lose weight, regardless of method.
A 2022 study in the European Journal of Endocrinology followed men with obesity and functional hypogonadism on liraglutide for 16 weeks. Participants lost weight and showed significant increases in total testosterone, with corresponding drops in estradiol — a pattern consistent with reduced conversion of testosterone to estrogen in fat tissue.
Effects on sperm parameters are less clear. Animal studies suggest GLP-1 receptors are present in the testes and may directly support sperm production, but human data on sperm count, motility, and DNA integrity remain limited. The European Academy of Andrology has called for larger, longer trials before recommending GLP-1s specifically for male infertility.
The “Ozempic Babies” Phenomenon
Online reports describe a surge of unexpected pregnancies among women on GLP-1 drugs — including some who were using hormonal contraception. The pattern likely reflects a combination of factors: rapid weight loss restoring ovulation in women with previously irregular cycles, and possible reduced absorption of oral contraceptives because GLP-1s slow gastric emptying.
The U.S. Food and Drug Administration updated the tirzepatide label in 2023 to advise women using oral contraceptives to switch to a non-oral method, or add a barrier method, for four weeks after starting the drug and after each dose increase. Semaglutide and liraglutide labels carry related warnings about contraceptive reliability and pregnancy.
Critical Cautions Before Conception
GLP-1 drugs are not considered safe in pregnancy. Animal studies have shown developmental harm at clinically relevant doses, and the FDA recommends discontinuing semaglutide at least two months before a planned pregnancy because of its long half-life. Tirzepatide guidance is similar; liraglutide clears more quickly.
For couples actively trying to conceive, fertility specialists generally recommend:
- Stopping GLP-1 medications well before attempting pregnancy — typically about 8 weeks for semaglutide, shorter for liraglutide
- Continuing weight-supportive habits — balanced diet, regular activity, adequate sleep — to preserve metabolic gains after the drug is stopped
- Discussing folate supplementation and prenatal nutrition early with a clinician
- Using non-oral contraception while still on a GLP-1 if pregnancy is not yet desired
The Society for Maternal-Fetal Medicine emphasizes that unintended GLP-1 exposure in very early pregnancy is not, on its own, a reason for termination. Emerging registry data have not shown a clear increase in birth defects, but prospective studies are still ongoing and definitive safety data are not yet available.
What the Evidence Adds Up To
Research suggests GLP-1 drugs can meaningfully improve the underlying drivers of infertility for many people with obesity, PCOS, or weight-related hypogonadism. They are not fertility treatments themselves, and they should not be used during pregnancy. But they may help create the metabolic conditions under which natural conception is more likely once the medication is appropriately stopped.
As with any prescription medication, decisions should be guided by a clinician familiar with both reproductive medicine and obesity care. The most reliable gains come from sustainable weight management — whatever tools that includes — followed by careful, well-timed conception planning.
Disclosure: This content is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider before making changes to your health regimen.