Peptide Safety in Pregnancy, Breastfeeding and Adolescence: What Studies Report

What the published literature actually covers

"Peptide" is a chemical category, not a single drug, and the amount of published human pregnancy data differs enormously between individual compounds. The human literature that reports pregnancy-related or reproductive outcomes and that is cited on this page concerns glucagon-like peptide-1 (GLP-1) receptor agonists: a population-based cohort analysis of second-line antidiabetic medicines including GLP-1 receptor agonists in early pregnancy reported on major congenital malformations after first-trimester exposure; a 2025 JAMA analysis examined gestational weight gain and pregnancy outcomes after GLP-1 receptor agonist discontinuation; a 2025 review in the American Journal of Obstetrics and Gynecology surveyed GLP-1 receptor agonist use in pregnancy and characterised the available human evidence as limited; and a 2023 review addressed GLP-1 receptor agonist safety questions in the preconception period.

This page is for educational purposes only and is not medical advice; consult a licensed physician about any question involving pregnancy, breastfeeding or the care of an adolescent. Nothing below describes a protocol, and no source cited here is presented as a basis for personal decisions.

Pregnancy: What Studies Report

First-trimester exposure compared with insulin

The largest human comparison cited here is a cohort study of second-line antidiabetic drugs used in early pregnancy, in which researchers compared first-trimester GLP-1 receptor agonist exposure against insulin and reported no meaningful increase in the risk of major congenital malformations in the exposed group. The study design was observational and restricted to people treated for diabetes, and the authors of a later pregnancy-focused review described the overall human dataset on GLP-1 receptor agonists in pregnancy as limited. A single reassuring malformation comparison in one clinical population is not the same body of evidence as the multi-outcome, multi-trimester data that exists for long-established obstetric medicines.

Discontinuation around conception

Because these drugs are widely used before pregnancy is recognised, part of the literature addresses what happens after they stop. A 2025 JAMA analysis examined gestational weight gain and pregnancy outcomes among people who had discontinued GLP-1 receptor agonists, and a 2023 review discussed safety considerations raised in the preconception period for these agents. Reviews of reproductive effects have also been published: a 2025 Journal of Clinical Endocrinology & Metabolism review assessed the effects of GLP-1 agonists on reproduction, and an earlier Human Reproduction Update review traced the role of GLP-1 in reproduction from physiology to therapeutic perspective.

A case report during pregnancy

Individual reports form part of the pregnancy record. A 2024 case report in JCEM Case Reports described hyperemesis gravidarum attributed to semaglutide in a pregnant patient. A case report documents one occurrence and, as a design, cannot establish how often an event happens or whether it is caused by the exposure; it functions as a signal that appears in the literature rather than as a measure of risk.

"What peptides are safe during pregnancy" — how the literature frames the question

The published sources cited here do not produce a list of peptides characterised as safe in pregnancy. They report specific outcomes, in specific populations, for specific GLP-1 receptor agonists: malformation risk after first-trimester exposure was compared with insulin in one cohort, gestational weight gain and pregnancy outcomes were examined after discontinuation in another analysis, and a pregnancy-focused review summarised the field while noting the limits of the human data. For peptide compounds outside this drug class — including research-use-only materials that have no approved human indication — no pregnancy-outcome study appears among the sources cited on this page. That is an absence of published evidence. An absence of published evidence is not evidence of safety, and it is not evidence of harm either; it means the question has not been answered in the literature reviewed here.

Breastfeeding: what the cited literature does and does not report

None of the sources cited on this page reported breastfeeding outcomes, human-milk transfer, infant exposure through milk, or effects on lactation. The reproductive-medicine reviews cited here addressed reproduction and pregnancy rather than lactation: one reviewed effects of GLP-1 agonists on reproduction, another reviewed GLP-1 physiology in reproduction, and the obstetric review was framed around use in pregnancy. Consequently, questions phrased as "are peptides safe while breastfeeding" or "what peptides are safe while breastfeeding" cannot be answered from the literature summarised here in either direction. Where a page like this has nothing to report, the accurate statement is that no data were found in the cited sources — not that a compound was found to be compatible with breastfeeding.

Adolescents: what the cited literature does and does not report

None of the papers cited on this page reported outcomes specific to adolescents. The clinical and review literature cited here was oriented to pregnancy, preconception, reproduction, polycystic ovary syndrome, gestational diabetes and perioperative care; for example, one review addressed obesity, polycystic ovary syndrome and infertility as a setting for GLP-1 receptor agonists, and a 2025 overview covered the pathophysiology and management of gestational diabetes. Clinical practice guidelines are also written for defined populations and indications rather than for general use; the 2023 multisociety guideline cited here was scoped to the management of patients with chronic coronary disease. Extending adult findings to a developing adolescent population is an extrapolation that the sources cited here do not support.

Adjacent literature: PCOS, fertility and gestational diabetes

Some of the most frequently cited peptide research near this topic concerns the period before pregnancy rather than pregnancy itself. A prospective, randomised, controlled, open-label trial in overweight or obese women with polycystic ovary syndrome examined combined metformin and semaglutide therapy and reported on body weight, metabolic parameters and reproductive outcomes. A 2020 review discussed GLP-1 receptor agonists as an avenue in obesity, polycystic ovary syndrome and infertility, and a 2025 review examined effects of GLP-1 agonists on reproduction more broadly. Separately, a 2025 overview described the pathophysiology and management of gestational diabetes, a condition that intersects with this topic because pregnancy-specific hyperglycaemia is managed with its own established treatment pathways. Preconception research does not answer questions about exposure during pregnancy, and the reviews cited here kept those two periods distinct.

Adverse Events in the Pregnancy-Adjacent Literature: What Studies Report

Three adverse-event themes appear in the cited sources:

• Severe pregnancy nausea and vomiting in a single case. A 2024 case report described semaglutide-induced hyperemesis gravidarum.
• Retained gastric contents despite fasting. Researchers examining patients before anaesthesia reported an association between GLP-1 receptor agonist use and increased residual gastric content, an observation relevant to procedural and airway-management contexts.
• Uncertainty itself, reported as a finding. The pregnancy review characterised the human safety data for GLP-1 receptor agonists in pregnancy as limited, and the preconception review framed safety around conception as an open question in the literature.

Verified sources at a glance

Limits of this evidence base

Several structural limits recur across the cited work. First, most human pregnancy data come from observational records of people treated for diabetes or obesity, such as the cohort that compared early-pregnancy GLP-1 receptor agonist exposure with insulin; randomised trials in pregnancy are not represented among the sources cited here. Second, the outcomes studied are narrow: malformation risk, gestational weight gain and pregnancy outcomes after discontinuation were the focus of one 2025 analysis, while long-term child development was not an outcome in the sources cited here. Third, reviews in this space have examined reproductive effects of GLP-1 agonists and GLP-1 physiology in reproduction without producing pregnancy, lactation or adolescent safety conclusions for peptides as a class. Readers of this literature therefore encounter a field in which one drug class has a small and growing pregnancy dataset, and the remainder of the peptide landscape has, in the sources cited here, none.

References

• Safety of GLP-1 Receptor Agonists and Other Second-Line Antidiabetics in Early Pregnancy (JAMA Internal Medicine, 2024)
• Gestational Weight Gain and Pregnancy Outcomes After GLP-1 Receptor Agonist Discontinuation (JAMA, 2025)
• Glucagon-like peptide-1 receptor agonist use in pregnancy: a review (American Journal of Obstetrics and Gynecology, 2025)
• Glucagon-like peptide-1 receptor agonists and safety in the preconception period (Current Opinion in Endocrinology, Diabetes, and Obesity, 2023)
• Semaglutide-induced Hyperemesis Gravidarum (JCEM Case Reports, 2024)
• Effect of GLP1 Agonists on Reproduction (The Journal of Clinical Endocrinology and Metabolism, 2025)
• The role of glucagon-like peptide-1 in reproduction: from physiology to therapeutic perspective (Human Reproduction Update, 2019)
• Obesity, Polycystic Ovary Syndrome, and Infertility: A New Avenue for GLP-1 Receptor Agonists (The Journal of Clinical Endocrinology and Metabolism, 2020)
• Effects of combined metformin and semaglutide therapy on body weight, metabolic parameters, and reproductive outcomes in overweight/obese women with polycystic ovary syndrome (Reproductive Biology and Endocrinology, 2025)
• Unveiling Gestational Diabetes: An Overview of Pathophysiology and Management (International Journal of Molecular Sciences, 2025)
• Glucagon-Like Peptide-1 Receptor Agonist Use and Residual Gastric Content Before Anesthesia (JAMA Surgery, 2024)
• 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA Guideline for the Management of Patients With Chronic Coronary Disease (Circulation, 2023)