Updated

Updated · HSPH News · Jun 18

Harvard Study Finds 1st-Trimester GLP-1 Use Not Tied to Major Risks in 3,600 Pregnancies

Updated

Updated · HSPH News · Jun 18

Harvard Study Finds 1st-Trimester GLP-1 Use Not Tied to Major Risks in 3,600 Pregnancies

Q: Could a gene that boosts weight-loss drug effects also hold the key to preventing severe morning sickness?

Possibly, but the evidence is early and does not show a prevention strategy yet. The strongest clue comes from genetics, not from using GLP-1 drugs in pregnancy. A large 23andMe-led genome-wide study found that a variant in the GLP1R gene, rs10305420, was linked both to better weight-loss response to GLP-1 medicines and to a lower risk of morning sickness in pregnancy. That suggests the GLP-1 pathway may influence nausea in pregnancy as well as appetite and weight regulation. Other genetic work also points in that direction. Studies of hyperemesis gravidarum, the severe form of morning sickness, have identified several genes tied to appetite and nausea biology, including TCF7L2, which may affect GLP-1 signaling. Together, these findings raise the possibility that the same biology behind GLP-1 drug response could help explain why some women develop severe pregnancy sickness. But this is not proof that GLP-1 drugs prevent morning sickness, and it is not a reason to use them during pregnancy. The new Harvard-led study is reassuring only about inadvertent first-trimester exposure, finding no substantial increase in major adverse outcomes such as non-live birth, congenital malformations, or abnormal fetal growth. Researchers and drug makers still advise stopping GLP-1 medicines before conception because safety data on sustained use in pregnancy remain limited. So the gene may offer a biological lead for future treatments, but for now it is a research signal, not a clinical answer.

2 articles · Updated · HSPH News · Jun 18

Nearly 3,600 pregnancies in women using GLP-1 drugs showed similar rates of non-live birth, major congenital malformations and abnormal fetal growth whether treatment continued into the first trimester or stopped.
The clearest example was non-live birth: 29.7% among women who continued GLP-1s early in pregnancy versus 27.1% among those who discontinued, according to the Harvard-led study published June 9 in Annals of Internal Medicine.
Researchers said the findings address a growing real-world issue, with GLP-1 dispensing in the 90 days before the last menstrual period and conception rising from 2 per 1,000 pregnancies in 2020 to 15 per 1,000 in 2024 across a broader cohort of 2.1 million pregnancies.
The study offers reassurance for inadvertent early exposure but does not support continued use later in pregnancy, because most women who kept taking GLP-1s received only one additional dispensation in the first trimester.

Sources

HSPH News2d ago

Harvard Study: Early Pregnancy GLP-1 Use Not Linked to Major Adverse Outcomes

health.yahoo.com2d ago

Use of GLP-1 drugs early in pregnancy should not cause alarm

Are popular weight-loss drugs causing more accidental pregnancies by making birth control pills fail?

Is it now riskier for pregnant women to stop taking weight-loss drugs like Ozempic than to continue them?

Could a gene that boosts weight-loss drug effects also hold the key to preventing severe morning sickness?

GLP-1 Receptor Agonists and Early Pregnancy: Large-Scale 2026 Data Offer Reassurance but Guidelines Still Advise Caution

Overview

Recent research led by Harvard in June 2026 brings reassuring news for women who were exposed to GLP-1 receptor agonists early in pregnancy. The study found that using these medications in the first trimester does not appear to significantly increase the risk of major adverse outcomes. Experts, including Dr. Sonia Hernandez-Diaz, advise that women who took GLP-1 drugs before knowing they were pregnant should not panic. This positive outlook is important as GLP-1 drugs have become more popular for managing diabetes and weight, leading to more women of reproductive age using them and facing accidental early pregnancy exposure.

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