Pregnancy Fatigue: Why You Are So Tired and What Helps

Why does pregnancy make you so tired?

Pregnancy fatigue is not just feeling a bit sleepy. Many people describe it as a bone-deep exhaustion that comes in waves and cannot be shaken off with an early night. There are real physiological reasons for this, and understanding them can help you feel less frustrated by it.

Progesterone. This hormone rises dramatically in the first trimester and has a powerful sedative effect. It is the same hormone that makes you feel drowsy before your period, but at much higher levels. Progesterone also lowers blood pressure and blood sugar, contributing to feelings of lightheadedness and fatigue.

Increased blood volume. By the end of pregnancy, your blood volume increases by around 50%. Your heart is working harder to pump this additional blood, which uses significant energy. In the first trimester, your body is rapidly building the placenta — an entirely new organ — which requires enormous metabolic effort.

Emotional energy. The mental load of pregnancy, including worry, planning, and adjusting to life changes, uses energy too. First-time parents in particular may experience heightened anxiety about the pregnancy, which can be draining.

Disrupted sleep. Particularly in the third trimester, frequent urination, difficulty finding a comfortable position, heartburn, restless legs, and vivid dreams can all fragment your sleep. Even when you spend more time in bed, the quality of sleep may be poor.

When is fatigue worst during pregnancy?

First trimester (weeks 6 to 12). This is often the most exhausting phase. Progesterone levels are surging, nausea may be making it difficult to eat well, and your body is doing enormous behind-the-scenes work building the placenta. Many people feel dramatically better once they reach the second trimester.

Second trimester (weeks 13 to 27). Often called the "golden trimester" because energy levels typically improve. Nausea eases, hormones stabilise, and you are not yet carrying significant extra weight. This is a good time to batch-prepare meals, organise the nursery, and attend antenatal classes.

Third trimester (weeks 28 onwards). Fatigue often returns as the physical demands increase. You are carrying significantly more weight, sleeping is harder, and your body is preparing for labour. This is normal and a signal to slow down and rest when you can.

Evidence-based tips for managing fatigue

Prioritise sleep. Go to bed earlier when possible. Even 30 minutes extra can make a difference. The NHS recommends sleeping on your side from 28 weeks onwards, as this is associated with a reduced risk of stillbirth. A pregnancy pillow can help you get comfortable.

Eat for energy. Small, frequent meals with complex carbohydrates (wholegrain toast, oats, sweet potato) and protein (eggs, nuts, yoghurt) provide steady energy. Avoid large sugary snacks that cause blood sugar spikes and crashes. Stay hydrated — dehydration worsens fatigue.

Gentle exercise. It may feel counterintuitive, but gentle activity such as walking, swimming, or prenatal yoga can boost energy levels. Regular exercise during pregnancy is recommended by NICE and is associated with better sleep quality, reduced fatigue, and improved mood.

Accept help. This is not the time to prove you can do everything. Delegate household tasks, say no to non-essential commitments, and rest when your body tells you to. If you have a partner, talk about redistributing responsibilities.

Short rests. A 20-minute nap during the day can be restorative without interfering with night-time sleep. If napping is not possible, even sitting quietly with your eyes closed can help.

Could it be anaemia?

While fatigue is normal during pregnancy, severe or persistent exhaustion can be a sign of iron-deficiency anaemia. According to NICE, anaemia affects approximately 1 in 5 pregnant people in the UK. Your iron levels are routinely checked at your booking appointment and again around 28 weeks.

Symptoms of anaemia beyond fatigue include pale skin, breathlessness on mild exertion, heart palpitations, dizziness, and feeling cold. If you suspect anaemia, ask your midwife for a blood test. Treatment typically involves iron supplements and dietary advice.

When to speak to your midwife

Some level of fatigue is expected and normal. However, speak to your midwife or GP if fatigue is so severe you cannot manage daily activities, you feel persistently low in mood or are losing interest in things (this could indicate perinatal depression), you have symptoms of anaemia, you experience excessive thirst and frequent urination (which could indicate gestational diabetes), or you are sleeping excessively but never feel rested.