Sleeping like a baby (is in your belly)

“You better sleep during pregnancy. Once the baby comes, you’ll never sleep again!”

Eye roll for every single time we’ve heard people say that. Clearly sleep matters, and during pregnancy, it’s an especially next level big deal.

Sleep affects prenatal development and delivery, not to mention immune system function, birth weight, preterm births, and many other aspects of health for both mom and baby.

And yet, due to some twist of cosmic cruelty, it’s really hard to sleep well during pregnancy! The National Sleep Foundation found that 78% of women reported experiencing disrupted sleep during pregnancy. This is related to inevitable hormonal changes, as well as pregnancy symptoms: everything from discomfort and snoring to frequent urination, not to mention the real anxiety surrounding birth and labor.

So how does sleep when a lady’s pregnant compare to sleep when she’s not? And who’s most likely to get the best sleep during pregnancy?

We dug into the vast quantity of sleep data collected on the Glow Nurture app (well over 8,000 years of pregnant sleep altogether!) to see how time in bed changes as the baby bump grows.

Prepare to be Pooped

If you’ve ever been pregnant, or spent time with someone who’s pregnant, you’ll know that pregnancy is one of the more exhausting things a body will ever experience. You are literally growing a baby inside of you. That’s freaking amazing, and your body needs an insane amount of energy to pull it off!

The first and second trimesters of pregnancy are times when the body will want and need sleep — and mommas-to-be find a way to make that extra sleep happen. Our data shows that starting early in pregnancy, women are spending more time in bed than they were pre-pregnancy. They sleep more and more in the early weeks, peaking just before week 10 of pregnancy; after that, sleep starts to decline.

By the onset of the third trimester, moms-to-be are starting to get less sleep than they were used to pre-pregnancy. As they zero in on delivery day, they’re getting nearly 30 minutes less-than-typical sleep per night. And that’s before the baby arrives….

Straight hours aside, sleep quality during pregnancy can be drastically different (typically worse!) than what most women are used. Researchers have seen that women experience a decrease in deep sleep, or “slow wave sleep” — the most restorative type — during pregnancy. Many women also find that they wake up more during the night when pregnant: their bladder is calling, their cramps are horrible, their bodies ache, the fetus can’t stop won’t stop wiggling.

Despite sleep being sporadic and short-lived in the prenatal period, snoring often gets serious during pregnancy! Studies show that 26 percent of women start snoring during pregnancy, and 35 percent of pregnant women report snoring three or more times a week!

According to Glow data, women who do snore during pregnancy find that their snoring starts to ramp up around the second trimester, and then intensifies as pregnancy progresses. This is because, as the uterus and baby grow, they begin pressing on the diaphragm; breathing gets more difficult. The extra stress in the lungs, combined with the swelling of the nasal passages (a byproduct of the extra estrogen pulsing through the body during pregnancy) leave many mommas-to-be making more noise than usual.

It’s official: sleep during pregnancy is hard. But to make matters worse, it’s harder for some women than for others. Next we’ll take a look at the haves and have-nots of pregnancy sleep.

Demographic Differences in Pregnancy Sleep

Sleep during pregnancy is partially a matter of effort, and partially influenced by circumstances beyond our control — age, race, and general demographics. It’s hard to say why people of different demographics have such different experiences with sleep during pregnancy, but there’s no mistaking the patterns that emerge from the data. Since we found the patterns, we feel it’s our responsibility to share, even though some of the findings are tough to stomach. Here’s what data from Glow Nurture reveals:

As if youth was not already the most desirable thing — young people have way more success sleeping during pregnancy than do more mature mamas-to-be. Pregnant women under age 25 get the most sleep per night, 25 to 35 year-old pregnant women get 15 fewer minutes of sleep than pregnant young adults do, and those 35 and over get the least sleep of all — half an hour less than the young’uns, and 15 minutes less than mid-aged moms. Our data shows this pattern to be consistent throughout the entirety of pregnancy.

We also saw in our data that experienced pregnant moms get less sleep, on average, than first time pregnant moms — a pattern that holds independent of age. The difference in the amount of sleep reported by first time moms vs experienced moms increases from about 9 minutes in the first and second trimesters to about 13 minutes in the third trimester.

Based on the data we have it’s hard to separate out whether this difference is due to biological differences between bodies that have given birth and those that have not, or to the busy mommy lifestyle (taking care of children is time-consuming and leaves less time for sleep!). Regardless, worth noting that sleep can change with each pregnancy a woman experiences.

A more troubling finding also emerged from our data: the fact that, on average, moms-to-be who identify as Black or African report getting less sleep than White and Hispanic/Latina moms-to-be. This is consistent with previous research findings, and with patterns we’ve seen in sleep data on the Glow app. But that doesn’t make it any less troubling. We followed up by sorting the sleep data according to income levels, but that did not reveal any significant patterns.

Do a handful of minutes really matter?

We’ve gone through a number of cases, slicing the data all sorts of ways to discern all we can about sleep during pregnancy. And yes, sometimes the discrepancies seem minor; we talk about a handful of minutes here, a half hour there. Do the spare minutes make a difference?

We answer with a resounding yes: Sleep is a vital component of strong maternal health, and every minute matters. Studies have shown that getting a good night’s sleep early in pregnancy leads to better health outcomes later on. Conversely, poor sleep in pregnancy can disrupt the immune system and cause a number of birth-related complications.

The most striking study we found compared first-time moms who slept seven or more hours per night to first-time moms who got six or fewer hours of sleep at night. Moms-to-be in the six and under group were almost five times more likely to have a C-section, and their average length of labor was ten hours or longer!

There’s still so much research to be done regarding sleep’s effect on pregnancy and what that means for our health. We pledge continue to do our part, as we can uniquely assess population-level health trends during pregnancy; this is near impossible to replicate in a lab environment or randomized control trial. We hope that our data, coupled with new research from the scientific community, will continue to demystify maternal and prenatal health — and help more doctors and families rest easy (or try to!).