Last updated: June 2026.
Many women expect early pregnancy fatigue—the bone-deep exhaustion that often characterizes the first trimester is well documented and widely discussed. But persistent or returning tiredness in the second trimester can feel surprising and, for women over 35, sometimes worrying. The second trimester is popularly described as the “honeymoon phase” of pregnancy, a period of renewed energy and reduced nausea. While this is true for many women, individual experiences vary considerably—and for some, fatigue remains a significant presence throughout this period.
For women who become pregnant after 35, the intersection of pregnancy-related physiological changes and the natural energy shifts that occur in mid-life can create a particularly layered experience of fatigue. Understanding what research suggests about second trimester tiredness—and the factors that may contribute to it—can offer helpful context for navigating this period. If you’re earlier in your pregnancy journey, our guide to getting pregnant after 35 covers what to expect before and during conception.
What Research Shows About Energy Changes Across Pregnancy
According to information from ACOG and other major medical organizations, fatigue is one of the most common pregnancy complaints across all trimesters. Research suggests that while many women experience an improvement in energy during the second trimester compared to the first, this is not universal. A significant proportion of pregnant women continue to experience notable tiredness throughout the middle trimester, particularly during weeks 14 through 28.
Several physiological factors are thought to contribute to second trimester fatigue, including continued increases in blood volume, shifts in cardiovascular demands as the body supports a growing placenta and fetus, changes in sleep quality, and the ongoing metabolic demands of fetal development. For women over 35, baseline sleep quality and recovery capacity may already differ from younger pregnancies due to age-related hormonal and physiological shifts.
The American College of Obstetricians and Gynecologists (ACOG) notes that fatigue in pregnancy is a normal response to the significant physiological demands of supporting a growing fetus, though fatigue that is severe, worsening, or accompanied by other symptoms always warrants clinical evaluation.
Physical Factors Contributing to Fatigue in This Trimester
By the second trimester, the body has undergone substantial cardiovascular adaptation. Blood volume increases by approximately 40–50% during pregnancy to support placental circulation, and the heart works harder to pump this increased volume. Research suggests this expanded cardiovascular demand—while entirely normal—can contribute to feelings of tiredness and reduced exercise tolerance, even for women who were active before pregnancy.
Iron-deficiency anemia is another common contributor to second trimester fatigue. The increased iron demands of pregnancy, combined with the expansion of red blood cell mass, mean that iron requirements rise significantly. The Centers for Disease Control and Prevention (CDC) recommends routine monitoring of hemoglobin and hematocrit levels during pregnancy; a healthcare provider can assess whether iron levels might be contributing to fatigue and discuss appropriate approaches.
Sleep disruption, which often intensifies as the uterus grows, also plays a role. Back discomfort, frequent urination, and the challenge of finding comfortable sleep positions can fragment nighttime sleep in ways that compound daytime tiredness. For women over 35, pre-existing sleep quality differences—which become more common through the late 30s and early 40s—can amplify this effect. Our article on sleep changes in perimenopause after 35 provides context on how hormonal shifts in this life stage affect rest even outside of pregnancy.
Thyroid Function and Second Trimester Fatigue
Thyroid dysfunction is more common in women over 35 than in younger women, and pregnancy places specific demands on the thyroid gland. The thyroid must produce roughly 50% more thyroid hormone to support both the mother’s needs and fetal development, particularly in the first and second trimesters before the fetal thyroid is fully functional.
Women with pre-existing thyroid conditions—including Hashimoto’s thyroiditis or subclinical hypothyroidism—may find that pregnancy challenges their thyroid function in ways that affect energy levels. Fatigue, brain fog, and a general sense of heaviness can all be thyroid-related symptoms that overlap with typical pregnancy tiredness. If you have a history of thyroid conditions or have noticed symptoms of thyroid dysfunction before pregnancy, ensuring your thyroid function is monitored during pregnancy is important.
Even without a prior thyroid diagnosis, women over 35 who experience pronounced second trimester fatigue may benefit from having thyroid function reviewed as part of their prenatal bloodwork. Undiagnosed subclinical hypothyroidism can develop during pregnancy and is both detectable and manageable with appropriate care.
How Pregnancy After 35 May Affect Energy Levels
Research directly comparing fatigue experiences between women over and under 35 during pregnancy is limited, but some studies suggest that older pregnant women may be more likely to report fatigue as a significant concern. This may be related to several factors: pre-pregnancy sleep quality, the physiological demands of carrying a pregnancy at an older age, the likelihood of having other caregiving responsibilities (including older children), and the greater prevalence of conditions such as thyroid dysfunction that can affect energy and are more common as women age.
Women over 35 are also more frequently monitored for gestational diabetes, which can affect energy levels. If you are experiencing significant fatigue alongside increased thirst, frequent urination beyond typical pregnancy levels, or other unusual symptoms, discussing this with your OB/GYN or midwife is worthwhile. Our guide to pregnancy after 35: risks, care, and what to expect covers the monitoring considerations in more detail.
Mental Load, Caregiving, and Energy in Pregnancy After 35
Fatigue in pregnancy is not exclusively physical. For many women over 35, pregnancy occurs alongside established careers, existing children or caregiving responsibilities, relationship transitions, or significant life demands that simply don’t pause when a pregnancy begins. The cumulative effect of physical pregnancy fatigue on top of an already full life is a real and often underacknowledged contributor to second trimester exhaustion.
Research on the “mental load”—the cognitive labor of planning, anticipating, and managing household and family needs—consistently shows that this burden falls disproportionately on women and is itself energetically demanding. During pregnancy, this load may increase as women take on additional planning for a new baby while managing existing responsibilities.
This is not a problem with a simple solution, but naming it is useful. If second trimester fatigue feels disproportionate to the physical changes of pregnancy alone, it may be worth examining what else is occupying cognitive and emotional bandwidth—and where, if anywhere, support or redistribution is possible. Discussing this with a partner, a therapist, or a healthcare provider can help identify what supports would be most meaningful in your specific circumstances.
Supportive Approaches: What the Evidence Suggests
While no single intervention will eliminate pregnancy fatigue, several evidence-based strategies may help support energy levels and wellbeing during the second trimester:
- Rest prioritization: Research consistently supports rest as a primary strategy for managing pregnancy fatigue. Short daytime naps (15–20 minutes) may help without significantly disrupting nighttime sleep.
- Nutritional adequacy: Adequate iron, protein, and complex carbohydrate intake supports sustained energy. A registered dietitian familiar with pregnancy nutrition can offer personalized guidance. For more on what nutrition looks like during pregnancy after 35, see our guide to nutrition during pregnancy after 35.
- Prenatal vitamins: Ensuring adequate prenatal vitamin intake—particularly iron, folate, and B12—can help address nutritional gaps that contribute to fatigue. For a closer look at what to look for, see prenatal vitamins after 35: what to look for and why they matter.
- Gentle physical activity: For women without contraindications, research suggests that moderate exercise during pregnancy is associated with improved energy, mood, and sleep quality. Walking and prenatal yoga are frequently cited in studies. Always confirm what is appropriate for your individual pregnancy with your healthcare provider.
- Sleep position adjustments: Sleeping on the left side with a pregnancy pillow for support may help improve sleep quality and reduce discomfort as the uterus grows.
- Thyroid and glucose monitoring: Women over 35 benefit from ensuring that thyroid function and blood sugar regulation are adequately monitored, as both conditions can manifest primarily as fatigue and may otherwise go undetected.
When Fatigue Warrants Medical Attention
While second trimester fatigue is common, certain patterns are worth bringing to your provider’s attention promptly. These include fatigue accompanied by shortness of breath at rest, heart palpitations, pallor, or dizziness—which may indicate anemia or other circulatory concerns. Fatigue combined with significant mood changes, persistent low mood, or feelings of hopelessness may also warrant evaluation for prenatal depression, which is more common than many women realize and is very treatable with appropriate support.
Trust your instincts: if your fatigue feels different from typical tiredness, or if something else feels “off,” reaching out to your care team for reassurance and evaluation is always appropriate. The first trimester experience can also provide a useful baseline — our guide to the first trimester after 35 covers what’s typical in the earliest weeks.
Frequently Asked Questions
Is it normal to still feel very tired in the second trimester?
Yes—while many women do experience an energy improvement in the second trimester compared to the first, fatigue can remain significant for some, particularly those experiencing sleep disruption, mild anemia, or other contributing factors. If fatigue is severe or worsening, discussing it with your OB/GYN or midwife allows them to assess for any underlying causes and offer supportive guidance.
Could anemia be causing my second trimester fatigue?
Iron-deficiency anemia is a common contributor to pregnancy fatigue and is more likely to develop in the second and third trimesters as iron demands increase. Routine prenatal bloodwork typically screens for anemia; if you’re concerned about your levels between scheduled checks, your provider can order additional testing. The approach to iron supplementation during pregnancy should be guided by a healthcare provider.
Does pregnancy fatigue after 35 differ from younger pregnancies?
Research directly comparing these experiences is limited, and individual variation is substantial. Some women over 35 report that pregnancy fatigue feels more pronounced, potentially related to pre-existing differences in sleep, recovery capacity, or other life demands. However, many women over 35 also report manageable fatigue levels. Your individual experience is most meaningfully discussed with your care team in the context of your specific health picture.
How can I manage fatigue while still being productive at work during pregnancy?
Strategies that some pregnant women find helpful include scheduling demanding tasks for times of day when energy is highest, communicating needs to supervisors when appropriate (without obligation), taking short rest breaks, staying hydrated, and keeping blood sugar stable with regular small meals. What works varies between individuals; experimenting within your own context and discussing significant challenges with your care team is a reasonable approach.
Can thyroid problems cause extra fatigue in the second trimester?
Yes. Thyroid dysfunction—including hypothyroidism and subclinical hypothyroidism—is more common in women over 35 and can cause fatigue that overlaps with typical pregnancy tiredness. Pregnancy itself places increased demands on the thyroid gland. If you have a history of thyroid conditions or notice thyroid-related symptoms, discussing thyroid function testing with your provider is worthwhile.
How does gestational diabetes affect energy during pregnancy?
Gestational diabetes can contribute to fatigue through the effect of blood sugar instability on energy levels. Women over 35 are among those at higher risk for gestational diabetes and are typically screened between weeks 24 and 28. If significant fatigue occurs alongside increased thirst, frequent urination, or other symptoms, raising these with your provider before the scheduled screening window may be appropriate.
Are there safe supplements I can take for pregnancy fatigue?
Beyond what is included in a prenatal vitamin—particularly iron, B12, and folate—there is limited evidence for additional supplements specifically targeting pregnancy fatigue. Any supplement use during pregnancy should be discussed with your OB/GYN or midwife, as some supplements that are commonly used outside of pregnancy may not be appropriate during it. Addressing any underlying nutritional deficiencies identified through bloodwork is typically the most evidence-based approach.
When does second trimester fatigue typically resolve?
For women who experience energy improvement during the second trimester, this typically occurs in the early weeks (around weeks 13–16). Those whose fatigue continues through the second trimester often find that energy fluctuates based on sleep quality, activity levels, and nutritional status rather than following a predictable pattern. Fatigue commonly intensifies again in the third trimester as the physical demands of pregnancy increase. If fatigue is consistently severe throughout the second trimester despite adequate rest and nutrition, it is worth discussing with your healthcare provider.
Key Takeaways
- Second trimester fatigue is common and does not affect everyone in the same way—individual experiences vary considerably.
- Contributing factors include cardiovascular changes, increased blood volume, sleep disruption, and potentially iron-deficiency anemia or thyroid dysfunction.
- Women over 35 may have additional factors that influence energy levels, including pre-existing sleep differences, thyroid function, and the cumulative demands of a full life alongside pregnancy.
- Supportive approaches—rest, balanced nutrition, prenatal vitamin adequacy, and appropriate gentle activity—are broadly evidence-informed, though always best tailored to individual pregnancies.
- Fatigue accompanied by shortness of breath, pallor, mood concerns, or thyroid-related symptoms warrants prompt discussion with your healthcare provider.
References
- American College of Obstetricians and Gynecologists. Fatigue During Pregnancy. ACOG. acog.org
- Centers for Disease Control and Prevention. Anemia During Pregnancy. CDC. cdc.gov
- National Heart, Lung, and Blood Institute. Sleep Deprivation and Deficiency. NIH. nhlbi.nih.gov
- Mayo Clinic Staff. Pregnancy Week by Week: Second Trimester. Mayo Clinic. mayoclinic.org
- American College of Obstetricians and Gynecologists. Having a Baby After 35. ACOG. acog.org
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.