Semaglutide (Ozempic®, Wegovy®, Rybelsus®) in First-Trimester Pregnancy
Semaglutide is a GLP-1 receptor agonist used for type 2 diabetes and weight management. Its use during pregnancy is generally not recommended,
Semaglutide:
• Crosses the placenta to an uncertain extent in humans.
• Causes significant weight loss and reduced caloric intake, which may adversely affect fetal growth.
• Has a very long half-life (~1 week), remaining in the body for weeks after discontinuation.
• Takes approximately 5–7 weeks for most of the drug to be eliminated.
• Manufacturers recommend stopping it at least 2 months before conception.
Major congenital malformations
Recent observational studies of women exposed to GLP-1 receptor agonists during early pregnancy have not demonstrated a clear increase in major birth defects compared with diabetic or obese control populations.
Reported findings:
• No consistent pattern of structural anomalies.
• No specific teratogenic syndrome identified.
• No clear increase in miscarriage rates attributable to the drug itself.
Risk of Miscarriage
Current human evidence does not clearly show an increased risk of miscarriage.
Miscarriage risk may be influenced more by:
• Maternal diabetes
• Obesity
• Advanced maternal age
• Other comorbidities
What if a woman discovers she is pregnant while taking semaglutide?
1. Stop semaglutide when pregnancy is recognized.
2. Do not terminate a pregnancy solely because of first-trimester exposure.
3. Offer routine prenatal screening.
4. Detailed fetal anatomical ultrasound at 18–22 weeks.
5. Additional growth surveillance if clinically indicated.
"Current human studies have not shown a clear increase in birth defects after inadvertent first-trimester semaglutide exposure. Because available data are still limited and animal studies showed adverse fetal effects, the medication should be discontinued once pregnancy is recognized. Detailed fetal anatomical assessment is recommended, but exposure alone is not considered an indication for pregnancy termination."
| Issue | Current Evidence |
|---|---|
| Major Birth Defects | No proven increase in human studies. |
| Miscarriage | No clear increase demonstrated. |
| Specific Anomaly Pattern | None identified. |
| Animal Studies | Fetal loss, growth restriction, and congenital malformations reported. |
| Recommended in Pregnancy | No. |
| Stop Before Conception | Ideally 2 months before conception. |
| Pregnancy Termination Solely Due to Exposure | Not recommended. |
| Follow-up | Standard prenatal care with a detailed fetal anomaly scan. |
There is currently no convincing evidence that semaglutide is teratogenic in humans, but it cannot be considered proven safe during pregnancy.
What does "teratogenic" mean?
A teratogen is an agent that causes a reproducible increase in major congenital malformations above the background risk.
Classic human teratogens include:
• Isotretinoin
• Thalidomide
• Valproic Acid
Semaglutide: Human data
• Have not demonstrated a significant increase in major congenital malformations.
• Have not identified a specific pattern of birth defects.
• Have not shown evidence of a classic teratogenic syndrome.
Therefore, based on current human evidence, semaglutide is not a proven human teratogen. Why is it still avoided in pregnancy?
Animal studies showed:
• Embryonic death
• Growth restriction
• Skeletal abnormalities
• Increased fetal loss
Bottom line
Semaglutide is not currently considered a proven human teratogen. It is classified as not recommended during pregnancy because of adverse animal data and insufficient human evidence, rather than because human studies have shown a definite teratogenic effect. The estimated risk after inadvertent first-trimester exposure appears much lower than with established teratogens such as isotretinoin or valproate.