Emily Oster

3 min Read Emily Oster

Emily Oster

Is Melatonin Dangerous During Pregnancy?

Q&A on vague guidelines

Emily Oster

3 min Read

Is melatonin safe for use in pregnancy? I know that there is some evidence that “low doses of melatonin (1 to 3 milligrams) are considered safe for the short term,” but what does that mean? Once a week? Once a month? The studies published online also seem to suggest that melatonin may even help lower the likelihood of having complications like preeclampsia and preterm birth.

—Sleepy mom of one anticipating adding one more

This type of vague statement — “low doses,” “short term” — is often a sign of limited data. It often means that we have no strong reason to be concerned but also no compelling direct evidence for safety. I would prefer in these situations that guidelines would say some version of that directly, instead of making vague statements about limiting consumption, but that’s rarely the case.

The case of melatonin in pregnancy is interesting, in part for the reasons you say at the end of your question. Melatonin is a hormone that occurs naturally in humans and that supports your circadian rhythms. Basically, it’s what tells you to fall asleep at night and wake up in the morning. There is a growing body of evidence that suggests that melatonin is important in pregnancy. In particular, genetic issues with melatonin production may be a cause of higher-risk pregnancy. 

A lady laying on beg during pregnancy
Cottonbro Studio / Pexels

Gestational diabetes, preeclampsia, and preterm birth have all been associated with issues around melatonin. This has led some to argue that melatonin supplements may help with these issues, but we do not have any good evidence yet that they do.

This set of data alone is all very positive —  not only does melatonin appear safe but also that it might be beneficial. However: what we do not have is any direct evidence on the use of melatonin supplements for insomnia in people. We know that melatonin in supplements is transferred to the fetus (just like naturally occurring melatonin is). We also know there is good safety data in rats, but also maybe some evidence of minor fetal growth issues in sheep. 

People are not rats or sheep, and it is hard to be sure how the doses translate. 

With all this — where can we possibly land? There is nothing in the data that would provide any strong reason for concern, and melatonin is therefore the first-line prescription when people face pregnancy insomnia. For someone who wants more airtight randomized controlled trial evidence, you’ll have to wait. 

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Jonah H
Jonah H
19 days ago

What gives me pause in the absence of robust safety data is the plausible mechanism linking placental melatonin concentration (which, as was mentioned in the post, has been demonstrated to increase from exogenous (supplemental) melatonin) with uterine contraction and induction of labor. Melatonin is being considered for its potential role in labor induction.
See the following paper and its citations: https://www.mdpi.com/2227-9059/10/12/3252#B9-biomedicines-10-03252:

“6. Melatonin and Labor Uterine contraction is essential to progress into active labor for vaginal birth (Figure 2). In the last decade, induction of labor has been a common practice performed with the intent of reducing risks to the mother and/or baby by simply calling an end to the pregnancy. Ideally, induced labor progresses to vaginal delivery, but most induced labors fail and become a caesarean delivery [45–47]. Caesarean section increases the fetal and mother mobility, such as postpartum hemorrhage and venous thrombosis [48,49]. Maternal melatonin levels increase with advancing gestation, peaking during labor and then falling rapidly after birth [50]. The myometrium (uterine muscle) expresses the melatonin receptor MT2, and it is more highly expressed in laboring myometrium, collected at intrapartum caesarean section, than in myometrium from non-laboring women [51]. It has been proposed that melatonin receptor 1B (hMTNR1B) synergizes with oxytocin to promote nocturnal uterine contractions [7]. In fact, in humans, spontaneous labor in term pregnancies is more often initiated and more babies are born at night [52], a time when the pineal gland secretes the hormone melatonin into circulation. Melatonin receptor expression in the human pregnant uterus has been reported only during labor. In late-term pregnancy, circulating melatonin is of fundamental importance to induce timing and degree of contractions; conversely, its acute inhibition with light suppresses myometrial contractions [53]. In the same study, melatonin was also shown to increase the expression of the protein connexin, a gap-junction protein necessary for myometrial cell communication and the synchronization of uterine contractions. In addition, another study underlined that as melatonin increases, so does the sensitivity of the myometrium to oxytocin-induced contractions [7]. Taken together, these in vivo and in vitro observations suggest that melatonin plays a biological role in the timing of the onset of spontaneous labor and the effectiveness of spontaneous uterine contractions in labor [52]. The manuscript by Rahman SA et al., 2019, evaluated the impact of light-induced modulation of melatonin secretion on uterine contractions in women during the late third trimester (~36–39 weeks) of pregnancy in two inpatient protocols. The result of this study confirmed that there is a positive relationship between melatonin concentrations and uterine contractions in women after ~35 weeks of pregnancy. Moreover, there are many potential applications of this discovery to provide a newmechanism for therapeutically influencing the timing of labor and childbirth, since endogenous melatonin levels can be suppressed by both light and pharmacologic agents, and melatonin receptors can be activated by melatonin. Regarding this interesting topic, there is a work in progress, a double-blind randomized placebo-controlled trial MILO (Melatonin as an adjuvant agent in the induction of labor), by Swarnamani K et al., 2021, that aims to test the hypothesis that the inclusion of melatonin will reduce the need for the caesarian section in induced labor delivery [9].”

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Milestones. We celebrate them in pregnancy, in parenting, and they’re a fun thing to celebrate at work too. Just a couple years ago I couldn’t have foreseen what this community would grow into. Today, there are over 400,000 of you here—asking questions, making others feel seen wherever they may be in their journey, and sharing information that supports data > panic. 

It has been a busy summer for the team at ParentData. I’d love to take a moment here to celebrate the 400k milestone. As I’ve said before, it’s more important than ever to put good data in the hands of parents. 

Share this post with a friend who could use a little more data, and a little less parenting overwhelm. 

📷 Me and my oldest, collaborating on “Expecting Better”

Milestones. We celebrate them in pregnancy, in parenting, and they’re a fun thing to celebrate at work too. Just a couple years ago I couldn’t have foreseen what this community would grow into. Today, there are over 400,000 of you here—asking questions, making others feel seen wherever they may be in their journey, and sharing information that supports data > panic.

It has been a busy summer for the team at ParentData. I’d love to take a moment here to celebrate the 400k milestone. As I’ve said before, it’s more important than ever to put good data in the hands of parents.

Share this post with a friend who could use a little more data, and a little less parenting overwhelm.

📷 Me and my oldest, collaborating on “Expecting Better”
...

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Comment “link” for an article with other tools to help you navigate risk and uncertainty.

#emilyoster #parentdata #riskmanagement #parentstruggles #parentingstruggles

I spend a lot of time talking people down after they read the latest panic headline. In most cases, these articles create an unnecessary amount of stress around pregnancy and parenting. This is my pro tip for understanding whether the risk presented is something you should really be worrying about.

Comment “link” for an article with other tools to help you navigate risk and uncertainty.

#emilyoster #parentdata #riskmanagement #parentstruggles #parentingstruggles
...

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Here’s why I think you don’t have to throw away your baby bottles. ...

Drop your toddlers favorite thing right now in the comments—then grab some popcorn.

Original thread source: Reddit @croc_docs

Drop your toddlers favorite thing right now in the comments—then grab some popcorn.

Original thread source: Reddit @croc_docs
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Just keep wiping.

Just keep wiping. ...

Dr. Gillian Goddard sums up what she learned from the Hot Flash  S e x  Survey! Here are some key data takeaways:

🌶️ Among respondents, the most common s e x u a l frequency was 1 to 2 times per month, followed closely by 1 to 2 times per week
🌶️ 37% have found their sweet spot and are happy with the frequency of s e x they are having
🌶️ About 64% of respondents were very or somewhat satisfied with the quality of the s e x they are having

Do any of these findings surprise you? Let us know in the comments!

#hotflash #intimacy #midlifepleasure #parentdata #relationships

Dr. Gillian Goddard sums up what she learned from the Hot Flash S e x Survey! Here are some key data takeaways:

🌶️ Among respondents, the most common s e x u a l frequency was 1 to 2 times per month, followed closely by 1 to 2 times per week
🌶️ 37% have found their sweet spot and are happy with the frequency of s e x they are having
🌶️ About 64% of respondents were very or somewhat satisfied with the quality of the s e x they are having

Do any of these findings surprise you? Let us know in the comments!

#hotflash #intimacy #midlifepleasure #parentdata #relationships
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Here’s what we know from a data standpoint:
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If you want to buy a seat for your lap infant, or bring a car seat for an older child, by all means do so! But the additional protection based on the numbers is extremely small.

#parentdata #emilyoster #flyingwithkids #flyingwithbaby #carseats #carseatsafety

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Here’s what we know from a data standpoint:
✈️ The risk of injury to a child on a plane without a carseat is very small (about 1 in 250,000)
✈️ A JAMA Pediatrics paper estimates about 0.4 child air crash deaths per year might be prevented in the U.S. with car seats
✈️ Cars are far more dangerous than airplanes! The same JAMA paper suggests that if 5% to 10% of families switched to driving, then we would expect more total deaths as a result of this policy.

If you want to buy a seat for your lap infant, or bring a car seat for an older child, by all means do so! But the additional protection based on the numbers is extremely small.

#parentdata #emilyoster #flyingwithkids #flyingwithbaby #carseats #carseatsafety
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Note: Survey data came from the ParentData audience and users of the Nanit sleep monitor system. Both audiences skew higher-education and higher-income than the average, and mostly have younger children. The final sample is 14,919 children. For more insights on our respondents, read the full article.

SLEEP DATA 💤 PART 2: Let’s talk about naps. Comment “Link” for an article on what we learned about daytime sleep!

The first three months of life are a chaotic combination of irregular napping, many naps, and a few brave or lucky souls who appear to have already arrived at a two-to-three nap schedule. Over the next few months, the naps consolidate to three and then to two. By the 10-to-12-month period, a very large share of kids are napping a consistent two naps per day. Over the period between 12 and 18 months, this shifts toward one nap. And then sometime in the range of 3 to 5 years, naps are dropped. What I think is perhaps most useful about this graph is it gives a lot of color to the average napping ages that we often hear.

Note: Survey data came from the ParentData audience and users of the Nanit sleep monitor system. Both audiences skew higher-education and higher-income than the average, and mostly have younger children. The final sample is 14,919 children. For more insights on our respondents, read the full article.
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Tag a Dad who this holiday may be tricky for. We’re sending you love. 💛

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Tag a Dad who this holiday may be tricky for. We’re sending you love. 💛
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#parentdata #postpartum #postpartumdepression #paternalmentalhealth #newparents #emilyoster

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#parentdata #postpartum #postpartumdepression #paternalmentalhealth #newparents #emilyoster
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#emilyoster #parentdata #parentingcommunity #lookslikedaddy #lookslikemommy

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#emilyoster #parentdata #parentingcommunity #lookslikedaddy #lookslikemommy
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Head to the newsletter for more and stay tuned for part two next week on naps! 🌙

#parentdata #emilyoster #childsleep #babysleep #parentingcommunity

SLEEP DATA 💤 We asked you all about your kids’ sleep—and got nearly 15,000 survey responses to better understand kids’ sleep patterns. Comment “Link” for an article that breaks down our findings!

This graph shows sleeping location by age. You’ll notice that for the first three months, most kids are in their own sleeping location in a parent’s room. Then, over the first year, this switches toward their own room. As kids age, sharing a room with a sibling becomes more common.

Head to the newsletter for more and stay tuned for part two next week on naps! 🌙

#parentdata #emilyoster #childsleep #babysleep #parentingcommunity
...

Weekends are good for extra cups of ☕️ and listening to podcasts. I asked our team how they pod—most people said on walks or during chores. What about you?

Comment “Link” to subscribe to ParentData with Emily Oster, joined by some excellent guests.

#parentdata #parentdatapodcast #parentingpodcast #parentingtips #emilyoster

Weekends are good for extra cups of ☕️ and listening to podcasts. I asked our team how they pod—most people said on walks or during chores. What about you?

Comment “Link” to subscribe to ParentData with Emily Oster, joined by some excellent guests.

#parentdata #parentdatapodcast #parentingpodcast #parentingtips #emilyoster
...

Humility. That’s why. That’s the whole reason.

#emilyoster #secondbaby #parentingjokes #parentinghumor

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#emilyoster #secondbaby #parentingjokes #parentinghumor
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Bug season is upon us. Besides annoyance, this can bring up safety concerns, particularly with ticks. They are carriers of diseases, most notably Lyme disease. So what’s the best course of action?

Prevention is key! I suggest:
⭐ Regular tick checks
⭐ Using bug sprays with DEET 
⭐ Wearing long sleeves and pants in the woods

Some parents worry about DEET, but repellants with up to 30% DEET are recommended by both the CDC and AAP. The data says you’re in the clear, so go for it. Enjoy your summer!

#parentdata #emilyoster #tickseason #bugbites #bugspray

Bug season is upon us. Besides annoyance, this can bring up safety concerns, particularly with ticks. They are carriers of diseases, most notably Lyme disease. So what’s the best course of action?

Prevention is key! I suggest:
⭐ Regular tick checks
⭐ Using bug sprays with DEET
⭐ Wearing long sleeves and pants in the woods

Some parents worry about DEET, but repellants with up to 30% DEET are recommended by both the CDC and AAP. The data says you’re in the clear, so go for it. Enjoy your summer!

#parentdata #emilyoster #tickseason #bugbites #bugspray
...