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Scientific Frontline: Extended "At a Glance" Summary: Effects of Semaglutide on Fetal Development
The Core Concept: Recent studies suggest that semaglutide, the active glucagon-like peptide-1 (GLP-1) receptor agonist in weight-loss medications like Ozempic and Wegovy, may restrict maternal blood flow to the uterus and lower oxygen levels in a developing fetus. The research raises critical questions about the prenatal safety of these increasingly common metabolic treatments.
Key Distinction/Mechanism: While GLP-1 medications effectively manage blood glucose and induce weight loss, their systemic physiological impact includes acute cardiovascular changes. Within two hours of administration in a pregnant animal model, the drug significantly decreased maternal cardiac output, directly resulting in diminished uteroplacental perfusion and restricted fetal oxygenation.
Major Frameworks/Components:
- Maternal Cardiovascular Response: Advanced magnetic resonance imaging (MRI) was used to measure a rapid decline in the volume of blood pumped by the mother's heart following drug administration.
- Uteroplacental Perfusion: The reduction in maternal cardiac output correlated directly with decreased blood flow to the uterus, disrupting a critical pathway for fetal nourishment.
- Fetal Hypoxia Risk: Fetal blood sample analyses and cardiovascular monitoring indicated acute reductions in oxygen levels, which are essential for healthy fetal growth and development.
Branches of Science: Developmental Biology, Fetal Physiology, Cardiovascular Physiology, Pharmacokinetics, and Obstetrics.
Future Application: These findings will direct longer-term longitudinal studies to determine if acute oxygen reductions impact sustained fetal growth and whether these physiological changes directly translate to human pregnancies, ultimately guiding clinical prescribing protocols for reproductive-aged women.
Why It Matters: With approximately 12 percent of US adults and millions globally using GLP-1 medications, unexpected pregnancies during treatment are increasingly common. Understanding fetal risks allows healthcare professionals and patients to make safe, informed decisions regarding diabetes management and weight-loss therapies prior to conception.
GLP-1 receptor agonists are increasingly prescribed for weight management, resulting in significant weight reduction for a large patient population. While medications such as Ozempic and Wegovy may also improve women’s chances of becoming pregnant, what happens to their fetuses if they continue to take the drugs during pregnancy?
In a new Adelaide University animal study involving pregnant sheep, researchers found that semaglutide—the active ingredient in these medications—significantly reduced blood flow to the uterus and oxygen levels in the developing fetus.
While the findings are preliminary and have not been demonstrated in humans, they raise important questions about the safety of GLP-1 receptor agonists during pregnancy, particularly for women who may conceive unexpectedly or continue taking the medication before realizing they are pregnant.
Although semaglutide is contraindicated during pregnancy—and clinical guidelines advise discontinuing treatment prior to conception—unplanned pregnancies occur among patients actively using the medication for diabetes management or weight loss.
The new research, published as a conference abstract in the journal Heart, Lung and Circulation, is helping researchers better understand the effects of GLP-1 medications into late gestation to determine how they might affect a developing fetus.
Adelaide University researcher Dr. Mitchell Lock said the potential effects of semaglutide taken during pregnancy remain poorly understood.
“While weight-loss medications have become incredibly popular, there’s still a lot we don’t know about how they might affect a developing baby,” Dr. Lock said.
“In this study, we wanted to understand what happens to the mother’s cardiovascular system and the blood and oxygen supply to the fetus when semaglutide is administered during pregnancy.
“Within two hours of administering semaglutide, we found that the amount of blood pumped by the mother’s heart had significantly decreased, reducing blood flow to the uterus and lowering oxygen levels in the developing fetus.
“Oxygen is essential for healthy fetal growth and development, so any reduction in its supply raises questions about what might happen if exposure to the drug continues throughout pregnancy.”
The sheep study used advanced magnetic resonance imaging (MRI) to measure maternal heart function and blood flow to the uterus before and after administering semaglutide. Researchers collected fetal blood samples and monitored blood pressure and heart rate to assess the drug’s immediate effects on the developing fetus.
In Australia, approximately 500,000 individuals are prescribed GLP-1 medications for diabetes management, with additional off-label and approved use for weight management. In the US, about 12% of adults use GLP-1 medications for weight loss.
Senior researcher Professor Janna Morrison said the findings highlight the need for further investigations into the potential effects of prolonged exposure to semaglutide during pregnancy.
“Our findings suggest a potential risk to fetal development, but we haven’t yet established whether these short-term changes affect fetal growth, what happens over a longer period of semaglutide use, or whether similar effects could occur in human pregnancies,” Professor Morrison said.
Current clinical guidelines stipulate that semaglutide is not recommended during pregnancy, and individuals planning to conceive are advised to discontinue treatment beforehand.
Published in journal: Heart, Lung and Circulation
Title: Do Weight Loss Drugs Impair Fetal Growth?
Authors: S. Cho, M. Lock, S. Holman, J. Minns, J. Tu, C. Macgowan, M. Seed, M. Wiese, J. Morrison
Source/Credit: Adelaide University
Edited by: Scientific Frontline
Reference Number: bio111026_01
