Is Melatonin Safe for Pregnancy? Risks, Benefits, and Medical Consensus (Clinical Summary)

This article summarizes clinical findings, potential benefits, risks, and current medical consensus on melatonin use during pregnancy.

Key Takeaways

• Melatonin naturally increases during pregnancy and plays a biological role in fetal development.
• Supplemental melatonin shows promise in small human trials, particularly for complicated pregnancies, but data remain limited.
• No large RCTs yet confirm melatonin’s safety as a sleep aid in healthy pregnant women.
• Medical bodies currently advise against routine melatonin use in pregnancy.
• If considered, low-dose options (≤2 mg, like Nutreska’s Nightcap) may align better with physiology—but only under medical guidance.
• Studies track outcomes like insomnia during pregnancy, birth weight, and hypertensive disorders; current human evidence that melatonin changes these is limited.

Introduction

Melatonin is a natural sleep hormone and a common supplement. The key question for expectant parents is simple: is melatonin safe for pregnancy? This brief explains what we know, what we don’t, and how clinicians think about dose and timing.

Bottom line up front: evidence that melatonin is safe in routine, healthy pregnancies is limited. Use only with clinician guidance.

With more than 12,000 monthly global searches for “melatonin for pregnancy,” this topic is not only highly relevant but also medically complex. While melatonin’s role in regulating sleep is well documented, its use during pregnancy requires careful scientific review.

Melatonin: The Basics

Melatonin sets the body’s internal clock. It helps sleep–wake timing and has antioxidant and anti-inflammatory effects.

Supplemental melatonin is commonly available in doses ranging from 0.5 mg to 10 mg, often far higher than the body’s natural nightly production (approximately 0.1–0.3 mg).

During pregnancy, melatonin physiology changes: natural secretion increases progressively and peaks during late gestation, suggesting it may play a role in fetal development.

Natural Role of Melatonin in Pregnancy

Clinical studies reveal that melatonin is more than a sleep hormone during pregnancy:

• Placental Transfer – Melatonin crosses the placenta, reaching fetal circulation. This suggests maternal melatonin may help regulate fetal circadian rhythms.
• Fetal Brain Development – Animal studies indicate melatonin protects against oxidative stress, supporting neurodevelopment.
• Labor and Delivery – Some evidence shows melatonin may work synergistically with oxytocin, influencing uterine contractions and timing of labor.

Melatonin is part of pregnancy biology in both mother and fetus. The question is simple: is supplemental melatonin safe?

Clinical Research: Melatonin and Pregnancy Outcomes

What outcomes do studies track? Common endpoints include insomnia during pregnancy, hypertensive disorders (including high blood pressure), fetal growth (e.g., birth weight), and neonatal adaptation. Reviews note limited evidence that melatonin changes these outcomes in low-risk pregnancies. Some small trials in complicated cases explore oxidative stress and placental function. When a study reports an association such as “increased the risk,” certainty is usually low and not enough for routine use.

1. Animal Studies

Most experimental data come from animal models:

• Neuroprotection: Studies in rodents and sheep demonstrate melatonin protects against hypoxic brain injury in fetuses.
• Placental Function: Melatonin supplementation improved placental efficiency and reduced oxidative stress in complicated pregnancies.
• Safety Signals: No major teratogenic effects (birth defects) were reported in standard dosing ranges.

While promising, animal data cannot be assumed to apply directly to humans.

2. Human Studies

Human research remains limited but is gradually emerging.

• Pre-eclampsia and Oxidative Stress: A 2017 trial in Melbourne tested 30 mg/day melatonin in early-onset pre-eclampsia. It prolonged pregnancy and reduced oxidative stress markers, with no adverse effects reported in mothers or infants.
• IVF and Fertility: Small studies in women undergoing in vitro fertilization (IVF) have tested melatonin (2–6 mg/day). Findings indicate improved egg quality and fertilization rates, but these studies were not pregnancy-safety trials per se.
• General Pregnancy Safety: No large-scale randomized controlled trials (RCTs) have yet evaluated melatonin as a sleep aid in healthy pregnant women.

Thus, while pilot trials show potential benefits, the evidence base is still too limited for routine medical endorsement.

Potential Benefits of Melatonin in Pregnancy

• Improved Sleep Quality: Insomnia is common in pregnancy, especially in the third trimester. Melatonin may help some patients and is non-addictive.
• Neurodevelopmental Support: Through placental transfer, melatonin may aid fetal brain development by reducing oxidative stress.
• Management of Complications: Emerging research suggests melatonin may help with hypertensive disorders of pregnancy (like pre-eclampsia), though this is still experimental.

Potential Risks and Unknowns

Supplemental melatonin raises safety questions:

• Long-Term Effects on Offspring: Human studies are too limited to confirm whether supplemental melatonin affects long-term child development.
• Hormonal Influence: Since melatonin regulates reproductive hormones, excess intake may theoretically disrupt maternal-fetal endocrine signaling.
• Dosage Uncertainty: Supplements often contain 3–10 mg per serving, far exceeding physiological nighttime levels. Clinical safety of these doses during pregnancy is not established.
• Drug Interactions: Melatonin may interact with antihypertensives, anticoagulants, and other medications commonly used in pregnancy.

Medical Consensus

Major bodies, including the American College of Obstetricians and Gynecologists (ACOG) and the NHS (UK), do not recommend melatonin in pregnancy because safety data are limited.

In the United States, the Food and Drug Administration (FDA) regulates melatonin as a dietary supplement rather than an approved drug for sleep. That means products are not FDA-approved for safety or efficacy prior to sale, and quality and dose can vary by brand.

Instead, they suggest:

• Non-drug sleep hygiene methods (light control, bedtime routines, limiting caffeine).
• Clinician-guided therapy if insomnia severely impacts health.

Nutreska’s Perspective: Nightcap Collection (≤2 mg Melatonin)

At Nutreska, our Nightcap collection contains up to 2 mg of melatonin per capsule, a dosage closer to the body’s natural physiological range than many over-the-counter products.

While Nightcap is designed for healthy adults, we advise:

• Pregnant or breastfeeding women should not take melatonin without explicit medical approval.
• If a healthcare provider considers melatonin appropriate, low-dose formulations (≤2 mg) may align better with natural melatonin levels compared to high-dose products on the market.

Transparency is key: until stronger clinical evidence emerges, caution is warranted.

Alternatives if You’re Asking “Is Melatonin Safe for Pregnancy?”

If sleep is hard during pregnancy, safer strategies include:

• Cognitive Behavioral Therapy for Insomnia (CBT-I)
• Improved Sleep Hygiene – consistent bedtime, minimizing screen exposure, cool dark rooms
• Relaxation Techniques – meditation, prenatal yoga, guided breathing
• Magnesium Supplements – sometimes recommended under physician supervision

Future Research Directions

Ongoing clinical trials are investigating:

• Melatonin in preventing pre-eclampsia and gestational diabetes
• Neuroprotection in high-risk pregnancies
• Long-term developmental outcomes in children exposed in utero

Results over the next decade will clarify whether melatonin becomes a mainstream therapy in maternal medicine.

Author’s Note

At Nutreska Wellness Labs, my work focuses on translating complex clinical evidence into practical health guidance. Our mission is to make wellness science transparent and accessible. When it comes to sensitive subjects like melatonin for pregnancy, the truth is simple: early data are promising, but the science is not complete. Until larger human studies arrive, use only with medical guidance.

— Dr. Linh Tran, PhD
Clinical Researcher, Nutreska Wellness Labs

References & Further Reading

Ejaz H, Bracey K, McPherson L, et al. Maternal Serum Melatonin Increases During Pregnancy and Levels Drop After Delivery. Frontiers in Endocrinology. 2021. Link

Vine T, Brown GM, Frey BN. Melatonin Use During Pregnancy and Lactation: A Scoping Review of Human Studies. Braz J Psychiatry. 2022;44:342-48. Link

Verteramo R, Silvestri L, Mampieri G, et al. The Role of Melatonin in Pregnancy and Early Life. IJMS. 2022. Link

MotherToBaby Fact Sheet (2024). Link

Sleep Foundation (2025). Link

NHS. Pregnancy, Breastfeeding and Fertility While Taking Melatonin. Link

Teoh AN, Alwan NA, Chen L, et al. Maternal Melatonin Levels and Temporal Dietary Intake. BMC Pregnancy Childbirth. 2023;23:150. Link

Bradfield Z, et al. Melatonin Supplementation in Late Pregnancy… BMJ Open. 2025. PDF