The science of pregnancy fatigue: why you’re so tired and how to cope

You’re growing a human being. Your body is working overtime, and you’re exhausted in ways you never imagined possible. If you find yourself wondering why simply existing feels like running a marathon these days, you’re not alone. Research shows an overwhelming 94.2% of pregnant women experience fatigue during pregnancy, with some studies placing this number as high as 98%.

Why am I so tired during pregnancy?

Pregnancy fatigue isn’t just “being tired” – it’s a complex physiological response that affects nearly every pregnant woman at some point. Let’s explore what’s happening in your body to cause this overwhelming exhaustion.

The hormonal hurricane

That wave of fatigue hitting you – especially in the first trimester – is largely thanks to progesterone, the pregnancy-supporting hormone that increases dramatically after conception. According to UCLA Health ob-gyns, progesterone has natural sedative effects, essentially telling your body to slow down and rest.

Pregnancy symptoms, including fatigue, increase sharply around 3-4 weeks gestation with noticeable peaks at weeks 4-5, 11, and 28, according to research published in Nature Digital Medicine.

Your body’s building project

Your metabolism is working harder than ever before. Blood volume increases by up to 50%, your heart pumps more blood, blood vessels expand to accommodate increased circulation, and your body produces more red blood cells. This cardiovascular transformation requires significant energy, leaving you feeling depleted.

The sleep disruption cycle

The relationship between fatigue and sleep quality is a vicious cycle during pregnancy. Research has found a significant inverse correlation between total fatigue scores and sleep quality – as fatigue increases, sleep quality decreases.

Up to 78% of pregnant women report disturbed sleep, with problems peaking in the third trimester. Common sleep disruptors include frequent urination, physical discomfort, heartburn, back pain, anxiety, and vivid dreams.

The anemia factor

Pregnancy increases your body’s demand for iron to support your growing blood volume and your baby’s development. When iron stores can’t keep up, pregnancy anemia can develop, worsening fatigue. The Cleveland Clinic notes that providers often recommend iron supplements or dietary changes when anemia is detected.

The trimester breakdown of fatigue

First trimester fatigue

The first trimester often brings the most dramatic fatigue for many women, despite the absence of a visible baby bump. This early exhaustion coincides with the most significant hormonal changes and the formation of the placenta.

Many pregnant patients report needing naps to make it through the day when they never needed naps before pregnancy, according to clinical observations from board-certified OB-GYNs.

Second trimester energy boost

Many women experience a welcome energy surge during the second trimester as hormones stabilize and the placenta takes over hormone production. However, research shows mean fatigue scores still increase from 23.53 in the first trimester to 25.78 in the second trimester on standardized assessment scales, according to a peer-reviewed study.

Third trimester exhaustion

As your baby grows significantly in the third trimester, fatigue often returns with greater intensity. Mean fatigue scores reach 26.46 in the third trimester based on standardized assessments.

Physical discomforts escalate during this time, with research showing breathlessness, foot pain, heartburn, incontinence, sleeping difficulty, pelvic pain, and water retention increasing toward the end of pregnancy, peaking around weeks 37-38.

How to cope with pregnancy fatigue

Listen to your body

Your fatigue is a biological signal that shouldn’t be ignored. When possible, rest when your body demands it, take short naps (20-30 minutes) when needed, prioritize sleep by establishing a consistent bedtime routine, and create a sleep-friendly environment.

For more specific sleep strategies during pregnancy, check out our detailed guide on evidence-based pregnancy sleep techniques.

Stay active (gently)

While it may seem counterintuitive, gentle movement can actually boost your energy levels. Consider walking outdoors in natural light, prenatal yoga, swimming, or stationary cycling. Always consult your healthcare provider before starting or continuing any exercise regimen during pregnancy.

Optimize your nutrition

Your eating habits can significantly impact your energy levels. Eat small, frequent meals to maintain stable blood sugar, include protein with each meal and snack, choose complex carbohydrates over simple sugars, increase iron-rich foods like leafy greens, beans, and lean meats, and stay hydrated with water throughout the day.

Seek support for mental health

Fatigue can both contribute to and be exacerbated by mood disorders during pregnancy. With 14% of childbearing individuals experiencing depression during the perinatal period and 6-8% experiencing anxiety disorders during pregnancy according to the Maternal Mental Health Leadership Alliance, mental health screening is essential.

Unfortunately, less than 20% of U.S. women are screened for maternal depression despite its connection to fatigue and mood issues. Don’t hesitate to discuss feelings of overwhelming fatigue with your healthcare provider, as it may indicate an underlying mood disorder requiring support.

Delegate and simplify

Now is the time to accept offers of help from friends and family, lower your standards for household tasks, use grocery delivery or meal prep services, consider hiring help if financially feasible, and say no to additional commitments.

When to talk to your doctor about pregnancy fatigue

While fatigue is normal during pregnancy, certain symptoms warrant medical attention: extreme fatigue that prevents daily functioning, fatigue accompanied by dizziness, shortness of breath, or heart palpitations, sudden onset of severe fatigue, fatigue with symptoms of depression or anxiety, or no improvement in energy levels during the second trimester.

Your healthcare provider may want to check for underlying conditions like anemia, thyroid disorders, gestational diabetes, or depression.

The postpartum fatigue transition

Pregnancy fatigue doesn’t end with delivery. Research shows postpartum fatigue affects 38.8% of women at 10 days, 27.1% at 1 month, and 11.4% at 3 months after birth, according to a population-based study.

For low-income American women, the numbers are even higher, with 63% reporting severe fatigue at both 1 and 3 months postpartum.

Planning for postpartum support is crucial, as sleep disruption becomes even more significant with a newborn’s feeding schedule.

Remember: this is temporary

The profound fatigue of pregnancy, while challenging, serves an important biological purpose – it forces you to slow down and conserve energy for the important work your body is doing. By implementing these coping strategies and giving yourself grace during this temporary but intense period, you can better manage your energy and focus on the incredible journey of bringing new life into the world.

Looking for more ways to improve your sleep during pregnancy? Download the Beginning app for personalized 3D sound journeys specifically designed to promote better sleep and reduce stress during pregnancy.