The main finding
In one sentence: A 2026 review that pooled seven cohort studies covering more than 40,000 exposed pregnancies found no statistically significant increase in birth defects, stillbirth, miscarriage, small babies or preterm birth after GLP-1 medicine exposure, but rated the certainty of the evidence as low.
A pooled result summarizes several studies that differed in who was enrolled, how long they ran and what they compared. It is not a prediction for one person.
On this page
Why this study matters
Individual studies of GLP-1 medicines in pregnancy are often small or limited to one country. A systematic review searches for every relevant study and, where possible, combines their results in a meta-analysis to get a more precise overall estimate. This 2026 review is the most recent such pooling we reviewed. For Canadian readers it gives an overview of what the observational evidence shows so far, and how much confidence can be placed in it.
Who was in the study
The review included seven cohort studies. Together they covered more than 40,000 pregnancies in which the pregnant person was exposed to a GLP-1 receptor agonist around conception or during pregnancy. The summary we reviewed does not describe the ages of participants, the countries covered, or how many people used the medicines for diabetes versus weight management. The medicines and doses varied across the included studies.
What the researchers did
This was a systematic review and meta-analysis. The authors searched five databases (PubMed, MEDLINE, Embase, Web of Science and Reprotox) from their start dates through January 2026. They selected cohort studies, which follow groups of exposed and unexposed people and compare outcomes, and combined their results statistically.
The outcomes were any congenital malformation (any birth defect), major congenital malformations after first-trimester exposure, and other pregnancy outcomes including stillbirth, spontaneous abortion (miscarriage), small for gestational age (babies smaller than expected), and preterm birth.
What they found
Exposure to a GLP-1 medicine at any time during pregnancy was not associated with a statistically significant increase in any congenital malformation. The pooled odds ratio was 1.11, with a 95% confidence interval of 0.82 to 1.51 (R32-C129). An odds ratio of 1.0 means no difference. A confidence interval is the range in which the true value most likely sits. Because the range includes 1.0, the review could not show a clear increase or decrease.
| Outcome | Pooled odds ratio (95% CI) | Note |
|---|---|---|
| Any congenital malformation, exposure at any time | 1.11 (0.82 to 1.51) | not statistically significant |
| Major congenital malformation, first-trimester exposure | 1.39 (0.73 to 2.65) | not statistically significant |
| Urinary malformations | 1.24 (1.05 to 1.47) | unadjusted data only |
No significant increase in risk was found for stillbirth, miscarriage, small for gestational age, or preterm birth. The summary we reviewed does not give the odds ratios for those outcomes.
One signal did reach statistical significance: urinary tract malformations, with an odds ratio of 1.24 (95% CI 1.05 to 1.47). However, this was based only on unadjusted data, meaning the studies did not account for other differences between exposed and unexposed people. The authors say this signal likely reflects residual confounding, that is, other factors that were not measured.
The authors describe the findings as cautiously reassuring about reproductive safety, but state that the certainty of the evidence remains low.
Side effects and people who stopped
This review looked at pregnancy and birth outcomes only. It did not pool side effects in the pregnant person, and the extracted data do not report discontinuation.
What this study does not tell you
- All seven studies were observational. None assigned treatment by chance, so differences between exposed and unexposed people could influence the results.
- The authors themselves rate the certainty of evidence as low. "Not statistically significant" does not mean "proven safe".
- The confidence interval for major birth defects after first-trimester exposure runs from 0.73 to 2.65. A real increase in risk cannot be ruled out.
- The urinary malformation signal is based on unadjusted numbers and should not be treated as an established risk, nor dismissed.
- Some of the seven studies may draw on overlapping populations. Findings from studies that share data should not be counted as independent confirmation of each other.
- The summary we reviewed does not describe the specific medicines, doses, or timing of exposure across studies, so it cannot answer questions about any one medicine.
What it means in Canada
This review summarizes observational evidence from outside Canada. It does not tell anyone what to do about their own medicine before or during pregnancy. For information about specific medicines, see semaglutide in Canada and tirzepatide in Canada. For what provincial plans pay for, see public drug coverage by province.
Common questions
Did the 2026 review find that GLP-1 medicines in pregnancy cause birth defects?
No clear increase was found. The pooled odds ratio for any birth defect was 1.11 (95% CI 0.82 to 1.51), and for major birth defects after first-trimester exposure it was 1.39 (95% CI 0.73 to 2.65).
How many pregnancies did the 2026 GLP-1 pregnancy review include?
It pooled seven cohort studies covering more than 40,000 exposed pregnancies, from a literature search running to January 2026.
What was the urinary malformation finding in the review?
A pooled odds ratio of 1.24 (95% CI 1.05 to 1.47) for urinary tract malformations was seen, but it was based only on unadjusted data and the authors say it likely reflects confounding.
Related reading
Other studies in this library that bear on the same question.
InPreSS: GLP-1 and other diabetes medicines in early pregnancy
GLP-1 medicines in the first trimester: a six-centre cohort
Continuing GLP-1 medicines into early pregnancy: a US study
GLP-1 medicines, drug interactions and oral contraceptives
Source
Original paper: Nusret Uysal, Maternal GLP-1 exposure pregnancy meta-analysis 2026, Scientific reports, 2026. PubMed: https://pubmed.ncbi.nlm.nih.gov/42420519/. DOI: https://doi.org/10.1038/s41598-026-61582-8. Funding: The summary we reviewed does not state the funding source. How we summarized it: abstract and extracted data.
This page explains a published study. It is not medical advice and does not describe whether a medicine is right for you. Talk to your doctor, nurse practitioner or pharmacist about your own situation. Reviewed and signed by two pharmacists registered in British Columbia, 2026-09-18.
Evidence records behind this page
Each record is a row in the clinical evidence file, taken from the published paper named above. The caution column is the limit the researcher recorded for that number.
This table scrolls sideways.
| Record | What the paper reports | Type | Population | Caution | Source |
|---|---|---|---|---|---|
| R32-C129 | A 2026 review did not find a clear overall increase in major birth defects after early GLP-1 exposure, but the evidence was low certainty and does not establish that these medicines are safe in pregnancy. | cross-trial context | pregnancies with periconceptional or gestational GLP-1 exposure | Low-certainty observational synthesis; urinary signal based only on unadjusted data; overlapping cohorts must not be counted as independent corroboration. | PubMed 42420519 |