Folate Deficiency Anaemia in Pregnancy

Folate deficiency anaemia in pregnancy is macrocytic anaemia from inadequate folate, caused by poor diet, increased demand, haemolysis, malaria, antiepileptic drugs, alcohol or malabsorption. Pregnancy raises folate needs, so deficiency is common where fresh vegetables are scarce. It matters because it causes neural tube defects, preterm birth and growth restriction.

• Risk factors: twin pregnancy, sickle cell disease, epilepsy treatment, alcohol, malaria, HIV.
• Folate stores last only 3 to 4 months.
• Treat only after excluding vitamin B12 deficiency.

Women have fatigue, pallor, sore tongue, mouth ulcers, poor appetite and sometimes diarrhoea, with weight loss. Neurological signs suggest vitamin B12 deficiency instead.

• Glossitis and angular stomatitis.
• No peripheral neuropathy in pure folate deficiency.
• Differential diagnosis: vitamin B12 deficiency, iron deficiency, haemolytic anaemia, hypothyroidism, liver disease, drug induced macrocytosis, myelodysplasia.
• Complications: severe anaemia, neural tube defect in the fetus, preterm birth, growth restriction, abruption, postpartum haemorrhage.

The approach is blood count and folate with B12 level.

• Haemoglobin below 11 g/dL, MCV above 100 fL, hypersegmented neutrophils on film, low reticulocyte count.
• Serum folate below 3 micrograms/L (below 7 nmol/L) or red cell folate below 100 micrograms/L.
• Serum vitamin B12 measured before treatment; ferritin; liver tests; TSH.
• Malaria test, HIV test, stool for parasites.

The principle is high dose folic acid after excluding B12 deficiency, and correction of the cause.

• Supportive: diet rich in green leafy vegetables, beans, liver and fortified flour; stop alcohol; treat malaria and infection.
• Pharmacological: folic acid 5 mg oral daily for 4 months or until delivery, then 400 micrograms daily; if vitamin B12 is low or unknown in severe anaemia, give cyanocobalamin 1000 micrograms IM before or with folic acid; ferrous sulphate 200 mg oral 8-hourly if mixed iron deficiency; artemether-lumefantrine 4 tablets oral at 0, 8, 24, 36, 48 and 60 hours for malaria.
• Procedures: blood transfusion for haemoglobin below 7 g/dL with symptoms.
• Special groups: women on carbamazepine, phenytoin or phenobarbital, and women with sickle cell disease or twin pregnancy, take folic acid 5 mg oral daily from before conception to 12 weeks, and continue it if anaemia persists; women with a previous neural tube defect take 5 mg daily from 3 months before conception to 12 weeks.
• Red flags: haemoglobin below 7 g/dL, neurological symptoms, jaundice, breathlessness, fever.
• Follow-up: reticulocyte count at 1 week and haemoglobin at 2 to 4 weeks; continue until haemoglobin is normal; recheck at 28 and 36 weeks; dietary counselling.