Can you take melatonin while pregnant?

If you're feeling short on sleep now that you're pregnant, you're not alone. Most women experience sleep problems during pregnancy. With so many adults turning to melatonin – and some parents buying melatonin for kids – you may be wondering if it's the miracle cure you need for a good night's sleep. Sadly, it's not so simple.

Melatonin is produced naturally by the body, and there's some limited evidence that supplements may be helpful for some sleep issues. But though some studies indicate that melatonin could be safe during pregnancy, we don't know enough about the potential risks and benefits to give it the okay.

What is melatonin?

Melatonin is a hormone that's important in sleep-wake cycles. Levels normally rise in response to darkness, peaking in the middle of the night and dropping just before morning. Limited research suggests that taking melatonin supplements before bed may help some people fall asleep more easily.

Melatonin is considered most useful to help people with temporarily altered sleep cycles, such as those suffering from jet lag. Some doctors may recommend it for a few nights after a trip abroad, for example.

As a sleep aid, melatonin's popularity has soared in recent years. Government-collected data from more than 55,000 adults shows that melatonin use increased from 0.4 percent of Americans in 1999 to 2.1 percent in 2018. According to the Council for Responsible Nutrition (CRN), the number of Americans who tried melatonin more than doubled from 2012 to 2022, from 4 percent to 10 percent.

What happens to melatonin levels during pregnancy?

The melatonin your body produces during pregnancy is important in many ways. Before birth, babies get melatonin from their mothers, and it seems to play a crucial role in fetal development.

During pregnancy, the placenta makes melatonin around the clock (not just at night). The levels in your blood at night rise over time, especially after 24 weeks. Just two days after birth, your levels go back down to the usual pre-pregnancy amounts.

In pregnant women with a serious condition called preeclampsia, melatonin levels are low. Some researchers think melatonin supplements might help keep this condition from becoming severe, thus helping women avoid or delay a preterm delivery.

Researchers are also studying the possible use of melatonin to treat gestational diabetes, intrauterine growth restriction (IUGR), and insomnia during pregnancy. In addition, some researchers think that melatonin supplementation may have a positive effect on fertilization rates and embryo quality. The hormone also plays a role in baby brain development.

A breastfeeding baby also obtains melatonin from Mom, with higher doses in nighttime breast milk. This is thought to positively affect a baby's circadian rhythms and provide antioxidant and anti-inflammatory effects, contributing to the baby's immunity.

Can you take melatonin during pregnancy?

It's not recommended. Though melatonin supplements are generally considered safe and don't have any serious side effects, there's not enough research on the safety of melatonin during pregnancy. So while melatonin could be fine – and even beneficial – during pregnancy, it's best to avoid it until more research is done.

Melatonin crosses the placenta, which means your baby would get increased dosages – besides the melatonin your body is already producing – if you take supplements. A typical dose of melatonin (between 1 and 3 mg) raises the level of melatonin in the blood up to 20 times normal levels. Experts don't know what effect this would have on your baby.

Most people are taking way too much melatonin. This could pose a particular danger to a fetus when it crosses the placental barrier.

- Jennifer Wu, M.D., an ob-gyn at Women's Health of Manhattan

One animal study showed that giving melatonin to pregnant rats resulted in a lower maternal weight, smaller litter size, smaller pups, and higher mortality.

And since melatonin supplements are considered a dietary supplement in the United States, they're less strictly regulated than drugs. That means some products may not contain what's listed on the label and may even contain unlisted ingredients.

One study of 31 commercial melatonin supplements found that 26 percent of the products contained serotonin, a non-listed contaminant. And more than 70 percent didn't meet their melatonin label claim within a 10 percent margin. The amount of melatonin ranged from less than 83 percent of the amount listed to over 478 percent of the labelled content. Variability from one lot of a specific product to another lot of the same product varied as much as 465 percent. 

Does melatonin work?

Whether you're pregnant or not, research shows that melatonin isn't a silver bullet when it comes to getting good sleep.

Based on trials of melatonin, researchers have generally found small or modest effects on sleep onset and little if any effects on overall sleep quality. The American Academy of Sleep Medicine doesn't recommend the use of melatonin as a treatment for problems falling asleep or insomnia, due to the lack of data supporting its effectiveness. (They do say that melatonin might be a treatment option for specific circadian rhythm sleep disorders, such as jet lag or shift work disorder.)

One study of 13 trials involving more than 5,800 patients found that the amount of time taken to fall asleep improved by 4.5 minutes after taking melatonin, but the overall total sleep time wasn't affected. In another analysis of 17 studies over a period of more than 20 years, melatonin reduced sleep onset by 4 minutes and increased total sleep duration by about 13 minutes.  

Also, melatonin may cause side effects including daytime sleepiness, dizziness, and fatigue.

What to try instead of melatonin while pregnant

It's no secret that it's often hard to get a good night's sleep while pregnant. According to a Polish study of more than 7,000 pregnant women, 77 percent reported sleep problems, including trouble falling asleep, waking often, waking too early, and sleeping too shallowly.

There are plenty of reasons for the struggle, including trouble getting comfy, frequent urination, leg cramps, heartburn, and anxiety.

"Unfortunately, sleep disturbances usually get worse as pregnancy progresses," says Dr. Jennifer WuOpens a new window.

Happily, there are plenty of safe options for improving your sleep. Here's what to try instead of melatonin while pregnant:

• Boost your body's own melatonin by dimming the lights and turning off bright screens like laptops, tablets, smartphones, and TVs at least an hour before bedtime. Artificial light tricks our body into thinking it's still daylight and keeps it from making the melatonin that helps us get to sleep.
• Improve your "sleep hygiene" by going to bed and getting up at the same time daily.
• Evaluate your bedroom. Is it a comfortable temperature? Dark and quiet? Invest in heavy or light-blocking curtains, good bedding, and a sound machine if you need to. Experiment with pregnancy pillows to find an assortment that's comfortable.
• Establish a relaxing bedtime ritual to cue your body that it's time to sleep. Play quiet music, take a warm bath, and enjoy a cup of pregnancy-safe herbal tea, for example.
• Do some gentle yoga or stretching before getting into bed to help your muscles relax.
• Snack before bedtime if you're trying to ward off morning sickness at night, but don't eat a big meal before heading to bed.
• If you're getting up to pee often, try cutting back on beverages at night.
• Stay away from caffeine in the afternoon and evening.
• Try deep breathing, progressive muscle relaxation, or guided imagery to fall asleep.
• Experiment with different sleeping positions.
• If you're anxious about pregnancy, connect with other expecting moms in person or online. Getting support from others going through the same thing is helpful. If you're a nighttime worrier, try writing down your thoughts, to-dos, and fears before bed and then setting them aside until morning.
• When you can, take a nap during the day to catch up on sleep. Don't overdo the length (half an hour is about right) or take your nap too late in the day, or you may shortchange your nighttime sleep.
• Talk with your provider about pregnancy sleep problems. If your insomnia is serious, they can help you weigh the risks and benefits of sleep medication.

Learn more:

What do pregnancy dreams mean?

First trimester pregnancy sleep

Second trimester pregnancy sleep