Sleep during pregnancy is notoriously unpredictable — and for women who become pregnant after 35, a combination of age-related changes and pregnancy-specific factors can make rest feel particularly elusive. Understanding why sleep shifts during pregnancy, and what approaches some women find helpful, can offer useful context for navigating this experience.
This article focuses on sleep changes across the trimesters of pregnancy, drawing on research from reproductive health and sleep medicine. The aim is to provide accurate, balanced information — not to prescribe solutions, since individual sleep experiences during pregnancy vary enormously and what helps one person may not help another.
Why Pregnancy Changes Sleep Architecture
Pregnancy involves dramatic hormonal, physical, and metabolic changes that collectively affect virtually every body system — including sleep. According to research published through the National Institutes of Health, sleep disturbances affect an estimated 78% of pregnant women, making them one of the most common pregnancy experiences.
The primary drivers of sleep changes during pregnancy include:
- Hormonal fluctuations — particularly rising progesterone in the first trimester (which can cause drowsiness but also affect sleep quality) and changes in melatonin and cortisol patterns
- Physical discomfort — increasing in the second and third trimesters as the body changes
- Frequent urination — a near-universal experience from early pregnancy onwards
- Emotional factors — including anticipatory anxiety, excitement, and the psychological adjustment to pregnancy
First Trimester: Drowsiness and Disruption
Many women find the first trimester paradoxically tiring — feeling sleepy throughout the day while also experiencing disrupted night-time sleep. Surging progesterone levels are thought to contribute to daytime sleepiness, while frequent urination, nausea (which can affect any time of day or night), and heightened anxiety may interfere with sustained nighttime rest.
For women over 35, there is sometimes an additional layer of anxiety in early pregnancy — particularly if the path to conception has been challenging, or if concerns about early pregnancy risks are heightened. Research suggests that anxiety is one of the most significant contributors to sleep disruption during pregnancy, which may make emotional support and stress management particularly important during this phase.
Sleep Position in the First Trimester
Sleep position becomes a topic of discussion during pregnancy, though in the first trimester, the uterus is still relatively small and position concerns are less pressing. Many providers begin discussing sleep position during the second trimester, as the growing uterus can put pressure on blood vessels when lying flat on the back.
Understanding how progesterone specifically affects sleep during this period may offer helpful context — for a deeper look at hormones and rest, you might explore the article on progesterone and sleep after 35.
Second Trimester: The “Easier” Phase — and Its Limits
The second trimester is often described as the most comfortable phase of pregnancy in terms of sleep, as nausea typically diminishes, energy levels often improve, and the fatigue of early pregnancy frequently eases. However, sleep disruptions do not disappear entirely.
As the abdomen grows, finding a comfortable sleeping position becomes progressively more challenging. Many providers suggest side-lying positions, particularly on the left side, as these may improve circulation. The use of supportive pillows — such as pregnancy wedge pillows or full-length body pillows — is something many women find helpful for positioning comfort.
Restless Legs Syndrome During Pregnancy
Restless legs syndrome (RLS) — an uncomfortable urge to move the legs, particularly at night — is reported more frequently during pregnancy than in the general population. Research suggests it may be related to iron deficiency, folate levels, and hormonal changes. If you are experiencing RLS-like symptoms during pregnancy, discussing them with your OB/GYN is worthwhile, as some contributing factors may be addressable.
Third Trimester: Sleep Becomes More Challenging
The third trimester typically brings the most significant sleep challenges. Physical factors — including fetal movement, shortness of breath from the growing uterus, heartburn, hip and back discomfort, and increasing urinary frequency — can make both falling asleep and staying asleep difficult.
Sleep-disordered breathing, including snoring and in some cases obstructive sleep apnea, can also emerge or worsen during pregnancy, particularly in the third trimester. Research suggests that pregnancy-related sleep apnea may be more common than generally recognized and can have implications for maternal and fetal health. If you or your partner notice significant snoring, gasping, or pauses in breathing during sleep, mentioning this to your provider is important.
Sleep and Fetal Health Considerations
Research has explored the relationship between maternal sleep duration and position and various pregnancy outcomes. While some studies suggest associations between very short sleep duration and certain outcomes, the research in this area is still evolving and most individual variations in sleep during pregnancy — including the disrupted, fragmented sleep that is nearly universal in late pregnancy — are not causes for alarm. If you have specific concerns about how your sleep may be affecting your pregnancy, your OB/GYN or midwife is best placed to provide personalized guidance.
Approaches Some Women Find Helpful
A range of approaches may support sleep quality during pregnancy. Individual responses vary, and it is always worth discussing any changes — including supplementation — with your healthcare provider during pregnancy.
- Establishing a consistent sleep and wake schedule where possible
- Using supportive pillows for positioning comfort
- Keeping the bedroom cool and dark
- Limiting fluid intake close to bedtime (while staying well-hydrated overall during the day)
- Managing heartburn through positioning and meal timing (in consultation with your provider)
- Addressing anxiety through evidence-based approaches such as relaxation techniques or speaking with a therapist
For broader context on navigating pregnancy after 35, exploring resources on what to expect during pregnancy after 35 may be helpful.
Frequently Asked Questions
Is it safe to take sleep aids during pregnancy?
This is an important question to discuss directly with your OB/GYN or midwife. Even supplements that are often considered low-risk outside of pregnancy — such as melatonin — have not been extensively studied in pregnant populations, and the safety of many sleep aids during pregnancy is not well established. Your provider is best positioned to advise you on what may be appropriate for your specific situation.
Why am I so tired in the first trimester but can’t sleep well at night?
This paradox is common in early pregnancy and is thought to relate to the effects of rising progesterone (which promotes daytime drowsiness) combined with physical factors — including nausea, frequent urination, and emotional adjustment — that can interfere with sustained nighttime sleep. Most women find this pattern improves in the second trimester as hormone levels stabilize somewhat.
Is it harmful to sleep on my back during pregnancy?
Current evidence suggests that sleeping on the back in late pregnancy (after about 28 weeks) may affect blood flow through the inferior vena cava due to the weight of the uterus, and some research has explored associations between back-sleeping and certain pregnancy outcomes. Most providers suggest sleeping on your side — particularly the left side — as a general recommendation in the third trimester, but if you occasionally wake up on your back, this is generally not a cause for significant concern. Discuss your specific concerns with your provider.
Will my sleep improve after the first trimester?
For many women, the second trimester brings some improvement in sleep quality as early-pregnancy symptoms ease. However, individual experiences vary, and sleep disruptions can persist or shift in character throughout pregnancy. Third-trimester sleep is commonly described as the most disrupted, primarily due to physical factors.
Key Takeaways
- Sleep disturbances affect the majority of pregnant women and are driven by hormonal, physical, and emotional factors that evolve across the trimesters.
- The first trimester often brings paradoxical drowsiness alongside disrupted nighttime sleep; the second trimester may offer some relief; the third trimester typically presents the most physical challenges to sleep.
- Pregnancy-related sleep-disordered breathing can emerge or worsen during pregnancy and should be discussed with a provider if suspected.
- A range of behavioral and positioning approaches may help support sleep quality; any supplements or medications should be discussed with your OB/GYN or midwife before use during pregnancy.
- Individual experiences of sleep during pregnancy vary considerably — what feels manageable to one woman may significantly impact another, and there is no single “normal.”
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.