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What Causes What
MECHANISM+ INCREASES

GLP-1 receptor agonist → Fertility

Higher GLP-1 receptor agonist increases Fertility.

In 28 infertile obese women with PCOS, twelve weeks of low-dose liraglutide added to metformin, then stopped for four weeks, was followed by more IVF pregnancies per embryo transfer than metformin alone: 85.7 percent versus 28.6 percent (Salamun 2018). The file is small and stacked.

Randomized trial · Contested · N=72

Supported by an experiment or a tightly identified design. Read the caveats.

Mechanism

Weight loss can restart ovulation in PCOS. Authors also talk about a direct incretin effect on the ovary and the lining of the womb. The trials count pregnancies, bleeding, ovarian size, or sperm shape. They do not count a testosterone number as the outcome. Salamun, Jensterle, Janez and Vrtacnik Bokal (2018) assigned 28 infertile obese women with PCOS to metformin or metformin plus liraglutide 1.2 mg a day for 12 weeks, then a 4-week washout, then IVF. Pregnancy per embryo transfer was 85.7 percent versus 28.6 percent (P=0.03). Weight loss was similar. abstract_only. Nylander, Frossing, Clausen and colleagues (2018) assigned 72 women with PCOS to liraglutide 1.8 mg a day or placebo for 26 weeks. The bleeding ratio rose more on drug (between-group 0.14). SHBG rose. Free testosterone and ovarian volume fell. abstract_only. Chen 2025 assigned 100 overweight women with PCOS to semaglutide plus metformin or metformin alone. After the combination phase, natural pregnancy was 35 percent versus 15 percent. full_text. Gregoric 2025 assigned 25 men with obesity, type 2 diabetes, and functional hypogonadism to weekly semaglutide or testosterone undecanoate. Normal sperm shape rose on semaglutide (2 percent to 4 percent). The testosterone arm lost concentration. full_text.

Caveats

Someone was assigned a pen, so the stamp is an RCT stamp. The file is small, often open-label, and often stacked on metformin, so confidence stays contested. Salamun is 28 women and a washout before stimulation. Nylander counts bleeding and ovarian volume, not a live birth. Chen stacks semaglutide on metformin. Gregoric compares semaglutide with a testosterone shot that can suppress sperm, in 25 men. These drugs are not studied as a treatment to take while pregnant. The IVF trial stopped the pen before stimulation. Did not hang the GLP-1 versus birth-control-pill proteomic file, the exenatide-dapagliflozin-phentermine stack, or the reviews. This page is a journal entry. It is not medical advice and not a reason to start or stop a drug.

Effect

qualitative. Salamun 2018 IVF PR/ET 85.7% vs 28.6% (lira+MET vs MET), N=28. Nylander 2018 bleeding ratio +0.14, N=72. Chen 2025 pregnancy 35% vs 15%.

Nodes

Lifestyle & environmentGLP-1 receptor agonistBiology & endocrinologyFertility

Named confounders

Cite this page

What Causes What. “GLP-1 receptor agonist → Fertility.” https://whatcauseswhat.org/edges/e-glp1-fertility (atlas updated 2026-09-02).

https://whatcauseswhat.org/edges/e-glp1-fertility

Papers