Iron in Pregnancy: Signs of Deficiency and Best Food Sources

Why iron matters

Iron is essential for making haemoglobin, the protein in red blood cells that carries oxygen around your body and to your baby. When iron levels are low, your body cannot produce enough haemoglobin, which means less oxygen reaches your tissues and your baby.

Moderate to severe anaemia can cause significant fatigue, increase the risk of preterm birth, lead to low birth weight, and increase the chance of needing a blood transfusion after delivery.

Signs of iron deficiency

Many symptoms overlap with normal pregnancy tiredness. Watch for extreme tiredness that rest does not improve, feeling breathless during normal activities like climbing stairs, pale skin (check inside your lower eyelids, lips, and nail beds), heart palpitations, feeling dizzy or lightheaded, headaches, cold hands and feet, restless legs particularly at night, and difficulty concentrating.

If you recognise several of these, mention them to your midwife. A simple blood test can check your haemoglobin and ferritin levels.

Routine testing

Your iron levels are checked at your booking appointment (around 8 to 12 weeks) and again at 28 weeks. NICE defines anaemia in pregnancy as haemoglobin below 110 g/L in the first trimester and below 105 g/L in the second and third trimesters.

Boosting absorption

Vitamin C significantly improves iron absorption from plant sources. Have a glass of orange juice with your iron-rich meal, add tomatoes to a lentil dish, or eat strawberries after a spinach salad.

Tea, coffee, and calcium can reduce iron absorption if consumed at the same time. If taking iron supplements, avoid tea or coffee for at least an hour either side.

Iron supplements and side effects

Iron tablets commonly cause constipation, nausea, and dark stools. If standard ferrous sulphate tablets cause too many side effects, ask your GP about alternatives such as ferrous fumarate or liquid iron preparations. Taking supplements every other day has been shown in some research to improve absorption while reducing side effects.