Melatonin During Pregnancy: Safety, Benefits & Side Effects

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Insomnia is a common problem of pregnancy, and about 80% of all pregnant women experience it in pregnancy (1). Melatonin is an over-the-counter drug for insomnia. You may consider the use of melatonin during pregnancy but after doctor consultation. However, the safety of the compound during pregnancy is unknown.

Insomnia in pregnancy may occur due to hormonal fluctuations and other physical issues such as backache, frequent peeing, gastroesophageal reflux disease (GERD), and fetal movements. Read this post to learn more about the safety, dosage, benefits, and side effects of melatonin during pregnancy.

What Is Melatonin?

Melatonin is a hormone produced by the pineal gland in the brain and is responsible for regulating the sleep-wake cycle. The level of the melatonin in the body changes according to the circadian rhythms of the body. It usually starts rising with the onset of darkness, stays raised between 2am and 4am, and begins to drop during the second half of the night to awaken you in the morning (2).

Besides natural light, a few foods like walnuts, tomatoes, olives, barley, rice, cherries, strawberries, and cow milk are known to influence the melatonin levels in the body, thereby affecting the natural sleep cycle (3).

Although the US Food and Drug Administration regulates supplements such as melatonin, their regulations and laws are not as strict as that of prescription or over-the-counter medications (4). So, it is essential to know how it affects you during pregnancy.

Is It Safe To Take Melatonin While Pregnant?

There is no scientific evidence to show that these supplements are completely safe, especially during pregnancy.

Leslie Swason, associate professor in psychiatry at Michigan Medicine’s Sleep and Circadian Research Laboratory, says, “Melatonin supplements are safe for adults in short-term use but because there haven’t been any long-term studies in humans, the long-term safety is unknown. (5)

During pregnancy, the melatonin level elevates naturally in the body. It usually starts rising from 24 weeks and increases significantly after 32 weeks of pregnancy (2). Hence, talk to your doctor about it before taking any supplements.

Although supplements can help to some extent, there are no sufficient studies to prove their efficiency in sleep initiation and sleep efficacy (6). So, it is always safe to opt for natural ways to fight insomnia during pregnancy. But, if you are diagnosed with sleep disorders such as restless leg syndrome or chronic insomnia, then consult your physician before taking a melatonin supplement.

How Much Of Melatonin Is Safe During Pregnancy?

There is no recommended dosage of melatonin for pregnant women. Swason says that smaller doses (0.5mg or less) of melatonin supplements produce similar levels that the brain produces naturally, and any dosage more than that would result in the rise of melatonin levels by 10 times (5).

The following section helps you understand how the melatonin dose can affect the pregnancy and the fetus.

What Are The Side-effects Of Melatonin Supplement During Pregnancy?

An animal study reported the following outcomes of taking melatonin supplement during pregnancy (7):

  • Lesser birth weight
  • Rare but possible infant mortality

There are limited studies on the effects of melatonin supplements during pregnancy.

In general, melatonin does have some side-effects like (8)

  • Sleepiness
  • Morning grogginess
  • Lower body temperature
  • Vivid dreams
  • Nausea
  • Dizziness

It is unclear how the melatonin intake of more than the normal levels during pregnancy can affect you and your child. The ongoing studies on melatonin and its relation to pregnancy are yet to provide convincing evidence to demonstrate its role. Therefore, it is recommended not to take melatonin supplements without the doctor’s advice.

Are There Any Benefits Of Melatonin When Pregnant?

Natural melatonin plays an important role in pregnancy. Its benefits in fetal-embryo development and pregnancy are as follows (2):

  • Induces circadian rhythm in the fetus.
  • Helps in the development of the nervous and endocrine system.
  • It is important for normal placental development.
  • It is a powerful antioxidant that aids in mitigating fetal morbidity or mortality due to intrauterine growth restriction (10).
  • It helps prevent preterm labor (12).

Before you plan a medical alternative for insomnia, you should try non-medical remedies first.

What Are Some Alternative Ways To Address Insomnia During Pregnancy?

Here are some alternatives for managing insomnia during pregnancy:

Non-pharmacologic interventions (1)

Sleep hygiene and sleep education: This is the first line of treatment considered for insomnia that helps in improving the quality of sleep without the use of any medicines. Here is what you can do to improve sleep hygiene.

  • Use dim lights during the night, if necessary.
  • Reduce the intake of fluids during late evening to avoid frequent visits to the bathroom at night.
  • Avoid spicy and deep-fried foods that can cause heartburn.
  • Prefer daytime naps.
  • Exercise for 30 minutes before going to bed.
  • Keep away electronic gadgets while you are in bed.
  • Avoid caffeine or nicotine use before going to bed.
  • Set your sleep and wake up time and follow it every day.

Behavioral therapy

  • Stimulus control: It helps in establishing a regular sleep/wake cycle. If you are unable to sleep then get up and do something that will stimulate sleep. Worrying about not being able to sleep can also trigger insomnia.
  • Relaxation techniques: Progressive muscle relaxation (PMR) technique helps in relaxing the muscles that help you get a good sleep. Abdominal deep breathing also helps in stimulating sleep.
  • Sleep restriction: It prevents the shift in circadian clock that further aids in preventing insomnia.
  • Cognitive therapy: It helps in developing a realistic expectation about sleep duration in the patients. It can be achieved through research data and considering the patient’s history of insomnia or sleeplessness.
  • Cognitive behavioral therapy for insomnia (CBT-I): It includes daily sleep logs, one session on sleep education, two sessions on stimulus control and sleep restriction, which is followed by two sessions on cognitive therapy. This is further followed by a session on sleep hygiene and ends with a session to combine the information from all the sessions.

Pharmacological Interventions

When non-medical interventions fail to treat insomnia, you may have to rely on medical treatment (1).

  • Hypnotics: Antihistamines like doxylamine, which is safe during pregnancy, is considered for treating moderate insomnia during pregnancy.
  • Antidepressants: If depression or anxiety disorder is the reason for insomnia, then it can be treated using an antidepressant.

Frequently Asked Questions

1. Does melatonin cause weight gain?

There is not much information that proves this association in humans. However, an animal-based research study demonstrated that maternal melatonin supplementation could lead to fetal weight gain (13).

2. How long does it take for melatonin to work for pregnant women?

Although it depends on several factors, melatonin supplements usually work well when taken before bedtime. However, you must refrain from taking melatonin (unless specified by your doctor) in pregnancy to prevent complications, especially if you are under any other medications (14).

Sleep disturbance during pregnancy can be aggravating, but sleep management can assist you in overcoming the problem to some degree. Though melatonin supplements are helpful for short-term use, there is no scientific evidence suggesting using melatonin during pregnancy is safe or effective. Therefore, it is best to look for natural and alternative ways such as sleep hygiene, sleep education, and behavioral and cognitive therapy to combat insomnia during pregnancy. If you have sleep disorders such as restless leg syndrome or chronic insomnia, talk to your doctor about the recommended melatonin dosage before using it.

This post is for informational purposes only and is not a replacement for a doctor’s consultation. Do not use any medication without talking to your doctor.

Key Pointers

  • Melatonin is a crucial hormone that regulates the sleep-wake cycle; it is known to be naturally increasing during pregnancy.
  • No current studies demonstrate the safety and effectiveness of melatonin during pregnancy.
  • However, you may use melatonin for the short term with your doctor’s consent.
  • Know that higher doses of melatonin are not advised and may cause headaches, nausea, and sleepiness during pregnancy.
  • You may try alternative relaxation methods and lifestyle modifications to manage insomnia during pregnancy.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Ali M. Hashmi, et al.; Insomnia during pregnancy: Diagnosis and rational interventions; NCBI (2016)
2. SE Voiculescu, et al.; Role of melatonin in embryo fetal development; NCBI (2014)
3.How the ups and downs of melatonin affect your snooze time; National Sleep Foundation (2018)
4. Melatonin: In depth; National Center for Complementary and Integrative Health, US Department of Health and Human Services
5. Jordyn Imhoff; Are melatonin supplements safe?; Michigan Medicine, University of Michigan
6. Rebecca B Costello,;The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature; NCBI (2014)
7. Singh HJ, et al.; Effect of melatonin supplementation on pregnancy outcome in Wistar-Kyoto and Sprague-Dawley rats; NCBI (2013)
8. Melatonin; HealthLinkBC
9. How to use melatonin for better sleep; The National Sleep Foundation
10. F J Valenzuela et al.; Circadian system and melatonin hormone: risk factors for complications during pregnancy; Obstetrics and Gynecology International (2015)
11. Zhao M, et al.; Melatonin prevents preeclamptic sera and antiphospholipid antibodies inducing the production of reactive nitrogen species and extrusion of toxic trophoblastic debris from first trimester placentae; NCBI (2017)
12. Domínguez Rubio AP,; Melatonin prevents experimental preterm labor and increases offspring survival; NCBI (2014)
13. Lewis J. Renshall et al., Melatonin Increases Fetal Weight in Wild-Type Mice but Not in Mouse Models of Fetal Growth Restriction; Frontiers in Physiology (2018)
14. Melatonin for Sleep: Does It Work?; Johns Hopkins Medicine.
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Dr. Christian Pope

Dr. Christian Pope is Board-certified in Obstetrics & Gynecology, and a Fellow of the American Academy of Obstetricians and Gynecologists. He is a long-standing medical staff member and past chairman of Obstetrics and Gynecology at St. Luke's Hospital of SouthCoast Hospitals in New Bedford, Massachusetts and is in private group practice at Hawthorn Medical Associates, Inc. He is a member... more

shreeja pillai

Shreeja holds a postgraduate degree in Chemistry and diploma in Drug Regulatory Affairs. Before joining MomJunction, she worked as a research analyst with a leading multinational pharmaceutical company. Her interest in the field of medical research has developed her passion for writing research-based articles. As a writer, she aims at providing informative articles on health and pharma, especially related to... more