Summary
New research found that people who used GLP‑1 drugs (like semaglutide/ozempic) before conceiving and stopped them prior to pregnancy had higher rates of some pregnancy complications and greater gestational weight gain than matched nonusers. The study is observational and cannot prove cause and effect.
Study design
Researchers analyzed several hundred singleton births within the Mass General Brigham system (2016–2025). They identified about 450 pregnancies with GLP‑1 exposure sometime between three years prior to conception and the first 90 days after conception. Timing of last prescription varied: roughly half had a GLP‑1 prescription within six months before conception, about one‑third stopped earlier, and ~17% had prescriptions after conception. Average prepregnancy BMI in the GLP‑1 group was about 36. Outcomes were compared with a nonuser group matched on prepregnancy BMI and BMI category.
Key findings
Compared with the matched nonuser group, those who had used then discontinued GLP‑1 medications showed higher rates of:
– Preterm birth
– Gestational diabetes
– Hypertensive disorders of pregnancy (including high blood pressure and preeclampsia)
They also gained more weight during pregnancy (about 30 lb/13.7 kg vs ~23 lb/10.5 kg) and a larger proportion met criteria for excessive gestational weight gain.
Interpretation and limitations
The results are associative, not proof of causation. Important limitations include confounding by indication: people prescribed GLP‑1s often have obesity, insulin resistance, or metabolic disease that independently increase pregnancy risk. Stopping GLP‑1 therapy can lead to rebound appetite and worsening glycemic control, which could contribute to preconception or early pregnancy weight regain and metabolic instability. GLP‑1 drugs also persist in the body for weeks, which is why guidance typically advises discontinuation before conception (commonly at least two months).
Safety data and unknowns
Animal studies at high doses have shown fetal growth restriction, structural abnormalities, and pregnancy loss, often alongside maternal weight loss; labels therefore advise against use in pregnancy. Human data remain limited and mixed: no clear, consistent signal for major birth defects has emerged, but evidence is insufficient regarding subtler outcomes or long‑term child effects. Experts emphasize uncertainty and the need for pregnancy‑specific research.
Clinical perspective
Obesity and metabolic disease are major drivers of obstetric complications. Abrupt discontinuation of GLP‑1 treatment may add metabolic instability on top of baseline risk. Given limited pregnancy safety data, most clinicians currently do not recommend continuing GLP‑1s during pregnancy; alternatives with more established pregnancy safety profiles (for example, insulin when indicated) are preferred.
Practical guidance for people planning pregnancy
– Discuss timing of stopping GLP‑1s and a transition plan with your clinician (many advise stopping weeks to months before conception).
– Focus on balanced nutrition to support appropriate weight gain for your BMI (regular meals/snacks, adequate protein, high‑fiber carbs, fruits/vegetables, healthy fats).
– Include gentle, regular activity as appropriate (short post‑meal walks, light resistance exercises).
– Address sleep, stress, and nausea, which influence appetite and glycemic control.
– Seek structured behavioral counseling if available — it can reduce excess gestational weight gain and some complications.
– Monitor blood sugar and metabolic health closely after stopping GLP‑1 therapy and during pregnancy.
Bottom line
Stopping GLP‑1 medications before pregnancy was associated in this study with higher rates of certain complications and more gestational weight gain, but underlying obesity and metabolic disease likely contribute substantially. GLP‑1s are not recommended during pregnancy; people planning pregnancy should work with clinicians on cessation timing, metabolic monitoring, and nutrition and activity plans. More targeted research is needed to clarify benefits and risks for pregnancy.
