Pregnant women feel sleepier, but they don’t necessarily get more sleep. The hormonal shifts of pregnancy create intense drowsiness, especially in the first trimester, yet the physical discomforts that come with growing a baby make it increasingly hard to stay asleep through the night. A 1998 National Sleep Foundation poll found that 78% of women reported more disturbed sleep during pregnancy than at any other time in their lives. The result is a frustrating gap between how much sleep your body demands and how much it actually gets.
Why the First Trimester Feels So Exhausting
The overwhelming sleepiness of early pregnancy is real, and it has a clear biological cause. As progesterone levels surge, the body rapidly converts progesterone into compounds that latch onto the same brain receptors targeted by sedative medications. These compounds boost the activity of your brain’s main “calm down” chemical, effectively slowing neural activity the way a sleep aid would. The effect is strong enough to make many women feel like they could fall asleep at their desk by mid-afternoon, even after a full night’s rest.
On top of the hormonal sedation, your cardiovascular system is working dramatically harder. Blood volume increases by 40% to 45% over the course of pregnancy, and that ramp-up begins in the first trimester. Your heart pumps more blood with every beat, and the extra workload translates to physical fatigue that compounds the hormonal drowsiness. Together, these changes explain why early pregnancy can feel like running a low-grade fever while jet-lagged.
Napping Picks Up, but Nighttime Sleep Suffers
Many pregnant women try to compensate for fatigue by napping during the day. About 80% of women in the second trimester report taking daily naps, with an average nap lasting roughly 65 minutes. By the third trimester, napping is still common (around 69% of women), but naps shorten to about 44 minutes on average. So while daytime sleep increases, it’s partly a response to worsening nighttime sleep rather than a sign of getting extra rest overall.
One actigraphy study measuring actual sleep (not self-reported estimates) found that pregnant women averaged just 6.87 hours of sleep per night. That’s below the 7-hour minimum most sleep guidelines recommend for adults. Women in the same study estimated their own sleep at about 7.3 hours, suggesting many don’t realize how fragmented their nights truly are.
What Keeps Disrupting Sleep at Night
The same progesterone that makes you drowsy during the day also fragments your sleep at night. It’s a genuine paradox: the hormone pushes you toward sleep, then prevents you from staying there. As pregnancy progresses, the list of disruptors grows longer. Nausea, heartburn, back pain, and frequent trips to the bathroom all chip away at continuous sleep. In late pregnancy, oxytocin (the hormone that triggers contractions) peaks at night, adding another source of waking.
Anxiety plays a role too. Worries about labor, the baby’s health, finances, or the logistics of parenthood can keep an expectant mother staring at the ceiling. Unlike physical discomfort, this kind of wakefulness tends to hit hardest during the quiet hours when there’s nothing else to focus on.
Sleep Disorders That Appear During Pregnancy
Pregnancy also raises the risk of diagnosable sleep conditions. Restless leg syndrome, that irresistible urge to move your legs when lying still, affects roughly 1 in 4 pregnant women. That’s about triple the rate seen in the general population. It tends to be worst in the third trimester and typically resolves after delivery, but in the meantime it can steal significant sleep.
Obstructive sleep apnea, where the airway partially collapses during sleep, also becomes more common as pregnancy advances. Weight gain, swelling of the airway tissues, and changes in breathing mechanics all contribute. In one study of higher-risk women, 10.5% met criteria for sleep apnea in the first trimester, rising to 26.7% by the third. A larger study of over 3,700 first-time mothers found the rate climbed from 3.6% early in pregnancy to 8.3% by mid-pregnancy. Many of these cases go unrecognized because snoring and daytime tiredness are easily dismissed as “normal” pregnancy symptoms.
How Sleep Changes After Delivery
There’s a common assumption that sleep gets worse after the baby arrives, and in some ways it does. Waking to feed a newborn is unavoidable. But the data on sleep architecture tells a more nuanced story. One study tracking women from about 35 weeks of pregnancy to three months postpartum found that total nighttime sleep actually increased slightly, from 7.35 hours to 7.55 hours. Women also fell asleep faster after delivery, with the time it took to drift off dropping from about 21 minutes to 14 minutes.
The trade-off was that time spent awake in the middle of the night increased by about 6 minutes per night postpartum, likely reflecting newborn feedings. Still, for many women, the relief from pregnancy-specific discomforts like heartburn, restless legs, and breathing difficulties means sleep feels more restorative even if interruptions continue.
Sleep Position in Pregnancy
You may have heard that sleeping on your left side is the safest position during pregnancy. A large NIH-funded study of more than 8,700 first-time mothers found that sleep position through about 30 weeks of pregnancy did not affect the risk of complications. Women who slept on their backs or right sides had the same rates of adverse outcomes as left-side sleepers. The researchers noted, however, that their data only covered sleep position up to 30 weeks. Previous research has linked back sleeping in late pregnancy (after 30 weeks) with higher risks, so the general advice to avoid sleeping flat on your back in the final weeks still holds. If you wake up on your back, simply roll to your side. There’s no evidence that brief episodes of back sleeping cause harm.
Practical Ways to Protect Your Sleep
Since the biological deck is stacked against restful sleep during pregnancy, small adjustments matter more than they normally would. Eating smaller, more frequent meals in the evening can reduce heartburn. Limiting fluids in the hour or two before bed cuts down on bathroom trips, though staying well-hydrated earlier in the day is still important. A pillow between the knees and under the belly can ease back and hip pain that worsens as the uterus grows.
Napping strategically helps too. Keeping naps under 30 minutes and before mid-afternoon gives you a recovery window without making it harder to fall asleep at night. If restless legs are a problem, moderate exercise earlier in the day and gentle stretching before bed can reduce symptoms. For persistent snoring or gasping during sleep, a sleep evaluation is worthwhile since untreated sleep apnea during pregnancy is linked to complications like high blood pressure and gestational diabetes.
The bottom line is that pregnancy creates an enormous drive to sleep more, and many women do spend more total time in bed or napping. But the quality of that sleep drops substantially, and actual measured sleep often falls short of what the body needs. The sleepiness is not laziness. It’s your body responding rationally to a massive physiological project.