Sleep during pregnancy is almost universally affected to some degree—and for women who are pregnant after 35, sleep challenges may intersect with age-related changes that were already beginning to emerge. From the frequent urination of the first trimester to the physical discomfort of the third, pregnancy has a way of reshaping sleep patterns in ways that many women find surprising, particularly if they hadn’t experienced significant sleep difficulties before.
Understanding what’s happening—and why—can help reduce the frustration that often accompanies poor pregnancy sleep. Research also suggests that addressing sleep proactively, with the support of a healthcare team, may be worthwhile for overall maternal wellbeing and pregnancy health.
This overview covers the most common sleep challenges during pregnancy, what research suggests about their causes, and evidence-informed approaches that some women find helpful.
What Research Shows About Sleep and Pregnancy
Research from the National Institutes of Health suggests that sleep disturbances are among the most commonly reported complaints during pregnancy, affecting an estimated 78–80% of pregnant women at some point. The nature and severity of sleep disruption tend to shift across trimesters.
In the first trimester, hormonal surges—particularly rising progesterone—often cause increased daytime sleepiness. In the second trimester, many women experience some improvement in sleep quality. The third trimester frequently brings the most significant challenges, including physical discomfort, restless legs, and the increasing difficulty of finding comfortable sleep positions.
First Trimester Sleep Patterns
Elevated progesterone in early pregnancy has a sedating effect, which is why many women feel exhausted in the first trimester despite spending more time in bed. Paradoxically, sleep quality during this phase may not be restorative—progesterone can increase the proportion of lighter sleep stages.
Nausea and frequent urination further disrupt sleep in the first trimester. Waking to use the bathroom multiple times per night is extremely common as the growing uterus begins to exert pressure on the bladder—a pattern that typically eases somewhat in the second trimester before returning in the third.
Third Trimester Sleep Challenges
The third trimester tends to be the most challenging for sleep. Several factors contribute:
Physical Discomfort
As the abdomen grows, finding a comfortable sleep position becomes increasingly difficult. Most pregnancy guidelines recommend sleeping on the side (often abbreviated as SOS—”sleep on side”) rather than the back, as back sleeping in late pregnancy can compress a major vein called the inferior vena cava, potentially affecting blood flow. Many women find that a pregnancy pillow—a curved support pillow—helps with positional comfort.
Restless Legs Syndrome
Restless legs syndrome (RLS)—characterized by uncomfortable sensations in the legs and an urge to move them, typically worsening at rest and in the evening—is more common during pregnancy. Research suggests that iron deficiency and hormonal changes may contribute. If you’re experiencing these symptoms, discussing them with your OB/GYN is worthwhile, as iron levels can be checked and addressed if needed.
Heartburn
Gastroesophageal reflux (heartburn) is very common in late pregnancy, when the growing uterus displaces the stomach upward and progesterone relaxes the lower esophageal sphincter. Lying flat can worsen symptoms, so some women find that sleeping with the head slightly elevated helps. Your healthcare provider can recommend appropriate antacid options if needed.
Understanding how sleep changes across all phases of the reproductive years can be valuable—exploring sleep changes after 35 provides a broader framework for these patterns.
Sleep Positions and Pregnancy Safety
One of the most frequent questions pregnant women have about sleep is which positions are safe. Current guidance from ACOG and the Royal College of Obstetricians and Gynaecologists (RCOG) suggests that sleeping on the side is preferable to sleeping on the back in the third trimester. Studies have found an association between late-pregnancy back sleeping and adverse outcomes, though whether this association is causal remains a subject of research.
Waking up on your back during the night is not a cause for alarm—research suggests the association is with sustained back sleeping rather than briefly rolling over. If this is a concern, a pregnancy pillow positioned behind the back can help prevent rolling.
Evidence-Informed Approaches to Better Sleep During Pregnancy
No single approach works for all pregnant women, and some common sleep strategies have limited pregnancy-specific evidence. The following are commonly explored and generally considered safe, though individual responses vary:
- Consistent sleep timing: Maintaining regular sleep and wake times may support circadian rhythm stability
- Daytime napping: Short naps (20–30 minutes) may help manage fatigue without significantly disrupting nighttime sleep
- Cool, dark, quiet sleep environment: Standard sleep hygiene principles that remain applicable during pregnancy
- Limiting fluids close to bedtime: This may reduce the frequency of nighttime bathroom trips, though hydration during the day remains important
- Pregnancy pillow: May improve positional comfort in the second and third trimester
- Relaxation techniques: Progressive muscle relaxation, breathing exercises, and gentle prenatal yoga have been explored with some positive findings for sleep quality
Sleep aids—including over-the-counter options and supplements such as melatonin—require discussion with your OB/GYN before use during pregnancy. Safety data for many of these products in pregnant women is limited.
When to Talk to Your Provider About Sleep
While poor sleep during pregnancy is common, there are circumstances where discussing it with your healthcare provider is especially important:
- You experience symptoms of restless legs syndrome or periodic limb movements
- You’re concerned about sleep apnea (loud snoring, witnessed breathing pauses, excessive daytime fatigue)
- Sleep deprivation is significantly affecting your mental health or daily functioning
- You’re considering taking any sleep aids or supplements
Sleep apnea during pregnancy has been associated with adverse outcomes including gestational hypertension and gestational diabetes, so it’s worth raising if you or your partner notices relevant symptoms. Exploring anxiety management during pregnancy is also relevant, as anxiety and poor sleep are often interconnected.
Frequently Asked Questions
Is it safe to use melatonin during pregnancy?
Melatonin is not well-studied in pregnant women, and its safety during pregnancy has not been established. Current guidance generally advises caution. If you’re considering melatonin or any other sleep aid during pregnancy, discuss it with your OB/GYN first.
Why am I so tired in the first trimester if I’m sleeping more?
First-trimester fatigue is largely driven by rising progesterone, which has sedating effects but may also alter sleep architecture—meaning sleep may be lighter and less restorative than usual. The body is also doing significant physiological work in early pregnancy. This fatigue typically improves in the second trimester for many women.
Is it harmful to sleep on my back during pregnancy?
Research has found an association between sustained back sleeping in late pregnancy and adverse outcomes, likely related to compression of the inferior vena cava. Most guidelines recommend sleeping on your side in the third trimester. If you wake up on your back occasionally, this is generally not a cause for alarm—but using a pillow to prevent sustained back sleeping is a reasonable precaution.
When should I talk to my doctor about poor sleep?
If sleep deprivation is significantly affecting your daily functioning, mental health, or wellbeing, it’s worth raising with your provider. This is also important if you have symptoms of conditions like RLS or sleep apnea, which have specific implications during pregnancy.
Key Takeaways
- Sleep disruption is extremely common during pregnancy, affecting an estimated 78–80% of pregnant women across at least one trimester
- First-trimester sleep is often affected by progesterone-driven fatigue and nausea; third-trimester challenges include physical discomfort, RLS, and heartburn
- Sleeping on the side is recommended in the third trimester; pregnancy pillows can support comfort and positioning
- Evidence-informed approaches—consistent sleep timing, relaxation techniques, daytime napping—may help, but individual responses vary
- Sleep aids and supplements require discussion with your OB/GYN before use; conditions like RLS and sleep apnea warrant clinical evaluation
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Individual health situations vary significantly. Always consult a qualified healthcare provider before making decisions related to your health, fertility, or pregnancy.
About the Author
Emily Carter is a women’s health writer focused on fertility, pregnancy after 35, and sleep changes in midlife. She writes research-informed, non-alarmist content to help women navigate reproductive and hormonal transitions with clarity and confidence.