Fatigue at 22 weeks of pregnancy, often situated in the second trimester, can be a confusing experience. While the severe exhaustion of the first trimester may have subsided, deep tiredness is a common concern during this mid-pregnancy phase. This fatigue is a direct consequence of the body undergoing rapid physiological and metabolic restructuring. The body works at an elevated baseline to support the fast-growing fetus and the dedicated organs of pregnancy. Understanding the factors driving this energy dip can guide effective strategies for rest and recovery.
Physiological Drivers of Second Trimester Fatigue
The experience of tiredness around 22 weeks is largely rooted in the massive cardiovascular and hormonal changes happening within the body. Maternal blood volume has expanded significantly, increasing by up to 45% compared to the pre-pregnancy state. This substantial increase requires the heart to work harder, moving a greater volume of fluid with every beat, which translates directly into increased maternal effort and fatigue.
This expanded blood volume consists of more plasma than red blood cells, leading to physiologic anemia. Hemoglobin levels may drop to around 11 g/dL, a normal threshold for mid-pregnancy, which reduces the blood’s oxygen-carrying capacity. Reduced oxygen transport contributes to feeling low on energy, even during light activity.
Hormonally, the high concentration of progesterone acts as a natural sedative. Progesterone levels continue to rise, contributing to daytime sleepiness. Furthermore, the body’s resting metabolic rate (RMR) has increased by approximately 10% to meet the energy demands of the growing pregnancy and the fully established placenta. This heightened metabolic effort means the body is continually burning more calories, leading to depletion if energy intake or rest is insufficient.
Sleep Quality and Lifestyle Factors
Even when the body demands rest, the physical realities of the second trimester can prevent restorative sleep, leading to cumulative fatigue. The growing uterus causes physical discomfort, necessitating a shift in sleeping positions. Lying flat on the back can place pressure on the inferior vena cava, potentially reducing circulation and causing fragmented sleep.
This often forces pregnant individuals onto their sides, requiring extensive use of pillows for support. Physical symptoms like heartburn and acid reflux become more pronounced as the uterus pushes upward on the stomach and progesterone relaxes the esophageal sphincter. Stomach acid can rise, especially when lying down, and these episodes frequently interrupt the sleep cycle, preventing deep rest.
Restless Legs Syndrome (RLS) is another common sleep disruptor, affecting approximately 22% of pregnant women and often worsening in the second trimester. The uncomfortable sensations in the legs create an urge to move, making it difficult to fall or stay asleep. The mental and emotional load of preparing for the baby, combined with anxiety, can also translate into nighttime worry that fragments sleep.
Identifying Medical Causes for Excessive Tiredness
While some fatigue is expected, excessive tiredness that does not improve with rest warrants a medical evaluation. The most common underlying medical cause is iron deficiency anemia, occurring when the body lacks enough iron to produce sufficient red blood cells for the expanded blood volume. A simple blood test can diagnose this condition, which, if left untreated, can intensify fatigue.
Thyroid dysfunction is another consideration, as the thyroid gland can become overactive (hyperthyroidism) or underactive (hypothyroidism) during pregnancy. Both conditions impact energy levels, with hypothyroidism being a cause of sluggishness and persistent tiredness that requires specific medication to manage.
Gestational diabetes, which typically develops around this time, can also manifest as fatigue. This condition impairs the body’s ability to effectively use insulin, leading to unstable blood sugar levels that result in energy crashes and exhaustion. Screening usually occurs between 24 and 28 weeks, but earlier testing may be indicated if symptoms are severe.
Hormonal changes and weight gain can lead to obstructive sleep apnea, often indicated by new or increased snoring. This condition causes brief, repeated interruptions in breathing during sleep, preventing restorative rest. This results in severe daytime tiredness, necessitating consultation with a healthcare provider.
Actionable Strategies for Boosting Energy
To combat fatigue, strategic adjustments to daily habits can improve energy levels. Prioritizing rest through strategic napping is effective; short naps (30 minutes or less) can restore energy without interfering with nighttime sleep. Establish a consistent, relaxing bedtime routine that avoids screen time and promotes winding down.
Maintaining consistent blood sugar levels is important, as mid-pregnancy metabolism can lead to energy dips if meals are skipped or imbalanced. Consuming small, frequent meals throughout the day that combine complex carbohydrates with protein helps stabilize energy. Examples include pairing whole-grain toast with an egg or apple slices with peanut butter.
Appropriate hydration supports energy, as the body needs more fluid to manage increased blood volume and metabolic processes. Drinking water consistently throughout the day, while limiting intake closer to bedtime, helps manage daytime energy and reduce nighttime trips to the bathroom. Gentle, low-impact exercise, such as walking or prenatal yoga, can boost energy by improving circulation and combating sluggishness.