Pregnancy Fatigue: Causes by Trimester and What Helps

Why pregnancy makes you so tired

Pregnancy fatigue has several causes that overlap:

• Progesterone: levels rise sharply in early pregnancy. Progesterone has a sedating effect and is the main reason for first trimester sleepiness.
• Increased blood volume and heart workload: blood volume rises by around 40 to 50 percent during pregnancy, and the heart pumps more blood every minute.
• Lower blood pressure in early and mid pregnancy, which can cause tiredness and lightheadedness.
• Building the placenta, which takes a lot of energy in the first trimester.
• Nausea and vomiting that make it hard to eat well.
• Poor sleep: needing to urinate at night, heartburn, leg cramps, restless legs, a growing belly, and the baby moving.
• Emotional changes: worry and mood changes affect energy.

Pregnancy fatigue by trimester

When pregnancy tiredness may be something else

Anemia

Iron deficiency anemia is common in pregnancy because the baby and the extra blood volume need iron. Look for tiredness that worsens, breathlessness, a racing heart, pale skin, headaches, feeling cold and cravings for ice. A blood test is offered at the first prenatal visit and again around 24 to 28 weeks.

Thyroid problems

An underactive thyroid causes tiredness, feeling cold, constipation and dry skin. It matters in pregnancy because thyroid hormone is important for the baby's brain development. It is treated with thyroid hormone tablets.

Hyperemesis gravidarum

Severe, persistent vomiting with weight loss and dehydration is hyperemesis gravidarum. It causes profound exhaustion and may need IV fluids and anti-nausea medicines.

Depression and anxiety

Depression during pregnancy is common and often missed because tiredness and sleep changes are expected. Persistent low mood, loss of interest, hopelessness, anxiety or guilt for more than 2 weeks should be discussed with your prenatal provider. It can continue after birth as postpartum depression.

Gestational diabetes

Gestational diabetes usually has no symptoms, but very high blood sugar can cause tiredness, thirst and frequent urination. Screening is done around 24 to 28 weeks.

Sleep disorders

Snoring and sleep apnea become more common in pregnancy, especially in the third trimester, and are linked to high blood pressure. Restless legs syndrome also becomes more common and disrupts sleep.

Preeclampsia

Tiredness with headache, swelling of the face and hands, vision changes or upper belly pain after 20 weeks can be preeclampsia. Report these symptoms right away.

How pregnancy fatigue is checked

Your prenatal provider will ask about your sleep, diet, mood, nausea and other symptoms, and check your blood pressure. Routine blood tests check for anemia. Thyroid tests, iron studies (ferritin), vitamin B12 and blood sugar tests may be added when fatigue is severe or comes with other symptoms. Questionnaires screen for depression.

How to cope with pregnancy fatigue

• Rest when you can. Go to bed earlier and take short naps of 20 to 30 minutes.
• Keep a sleep routine: consistent bedtimes, a cool dark room, and no screens for an hour before bed.
• Sleep on your side in the second half of pregnancy, with pillows between your knees and under your belly.
• Stay active: about 150 minutes a week of moderate activity, such as walking, swimming or prenatal yoga, improves energy and sleep, unless your provider advises otherwise.
• Eat small, frequent meals with protein and complex carbohydrates to keep energy steady. Include iron-rich foods such as lean red meat, beans, lentils and fortified cereals, with vitamin C to help absorption.
• Take your prenatal vitamin with folic acid, and iron if prescribed.
• Drink enough fluids during the day, and reduce drinking in the hour before bed to cut night-time trips to the bathroom.
• Limit caffeine to under 200 mg a day, about one 12-ounce cup of coffee.
• Ease heartburn with smaller evening meals and by raising the head of your bed.
• Ask for help with chores and childcare, and cut back on nonessential commitments.
• Talk about how you feel with your partner, friends or provider.

Frequently asked questions

When does pregnancy fatigue start?

Fatigue can start as early as 1 to 2 weeks after conception, sometimes before a missed period, as progesterone rises. It is usually strongest from about 6 to 12 weeks and often improves in the second trimester, before returning in the third trimester.

Why am I so tired in early pregnancy?

Rising progesterone has a sleep-inducing effect, and your body is working hard to build the placenta, increase blood volume and support the growing baby. Nausea, vomiting and poor sleep add to the exhaustion. For most people, energy improves around weeks 12 to 14.

Is extreme fatigue in pregnancy normal?

Feeling very tired is common, especially in the first and third trimesters. Exhaustion that stops you functioning, worsens over time, or comes with breathlessness, a racing heart, low mood, extreme thirst or severe vomiting is not something to put up with. Ask your provider for checks for anemia, thyroid problems and depression.

Can pregnancy fatigue be a sign of anemia?

Yes. Iron deficiency anemia is common in pregnancy and causes tiredness, breathlessness, pale skin, headaches and a racing heart. A simple blood test diagnoses it, and iron supplements usually improve energy within a few weeks. Your provider tests for anemia routinely during pregnancy.

Does pregnancy fatigue come back in the third trimester?

Yes, for many people. Carrying extra weight, discomfort, heartburn, frequent urination, leg cramps and the baby's movements disturb sleep in the third trimester. Side-sleeping with pillows, naps, gentle activity and smaller evening meals can help.