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|Folic acid (B9)|
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Synonyms and Keywords: Folic acid deficiency
According to a study, the greatest benefits from fortification were predicted in MI prevention, with 16,862 and 88,172 cases averted per year in steady state for the 140-mcg and 700-mcg fortification levels, respectively. These projections were 6,261 and 38,805 for colon cancer and 182 and 1,423 for Neural tube defects , while 15 to 820 additional B-12 cases were predicted. Compared with no fortification, all post-fortification strategies provided QALY gains and cost savings for all subgroups, with predicted population benefits of 266,649 QALYs gained and $3.6 billion saved in the long run by changing the fortification level from 140-mcg/100-g enriched grain to 700-mcg/100-g.
This study indicates that the health and economic gains of folic acid fortification far outweigh the losses for the U.S. population, and that increasing the level of fortification deserves further consideration to maximize net gains.
Reticulocytosis can be assessed at the end of the first week of therapy. It is important to determine completeness of response after 8 weeks of therapy, when blood counts should have normalized. Homocysteine levels can be used to monitor response. Inadequate response indicates a coexisting cause of anemia, such as iron deficiency or vitamin B12 (cobalamin) deficiency.
A year 30 year old woman (gravida 4, para 3) was admitted at 33 weeks gestation with worsening fatigue and shortness of breath on exertion over a month. Recently she noticed occasional gum bleeding and easy bruising. She reported that her appetite had decreased and attributed this to pregnancy related nausea. She denied any fever or night sweats. There was no history of alcohol abuse or dietary restriction. She had no history of any medication and all her previous pregnancies had been uneventful.
She was pale with few petechiae seen on the buccal mucosa. Her blood pressure was 120/80 mm Hg with a trace of protein detected on urine dipstick. There was no lymphadenopathy or splenomegaly palpable. The remainder of the clinical examination was unremarkable.
A full blood count revealed a macrocytosis with a severe pancytopenia. Haemoglobin of 70 g/L with a MCV of 105 fL , platelets were decreased 14×109/L and neutrophils were also low 0.5×109/L (1.7–7.5×109). Her last recorded haematological profile 5 months ago was within normal limits. Reticulocyte count was decreased 8×109/L. RFTs, LFTs and coagulation screen were normal. A blood film showed macrocytes. Hypersegmented neutrophils and thrombocytopenia were also seen. Ferritin and vitamin B12 level were normal. Serum folate was subtherapeutic at 2.5 ng/mL (4.6–18.7 ng/mL). An autoimmune screen was unremarkable. Antitransglutaminase antibodies were also negative.A bone marrow aspirate was hypercellular with megaloblastoid features. Early erythroid precursors and giant metamyelocytes were seen.
She was transfused with two units packed red cells and one adult dose of platelets. She was then started on folic acid 5 mg daily. A single dose of 1 mg hydroxycobalamin was also administered. A week later, the neutrophil count had recovered (1.5×109/L) with an increase in platelet count (25×109/L)
Outcome and follow-up
Her counts normalized and she gave birth to a healthy male baby. His full blood count was normal and there were no signs of neurological compromise.
Folate deficiency is a cause of macrocytosis in pregnancy. If left untreated, it could progress to severe megaloblastic anaemia with pancytopenia. Peripheral blood film may reveal macrocytic anaemia and hyper-segmented neutrophils. Bone marrow examination could demonstrate megaloblastic changes reflecting ineffective haematopoiesis and resultant bone marrow failure.
In the majority of developed countries, folic acid supplementation (at least 400 µg) is recommended for 2–3 months prior to conception and throughout pregnancy into the postpartum period. This been adopted as a worldwide strategy to reduce the incidence of fetal neural tube defects (NTD) such as anencephaly, spina bifida and meningomyelocele. This may also lower the risk of other congenital anomalies and adverse pregnancy outcomes such as pontaneous abortions, placental abruption and low birth weight.
Folate deficiency is most often a result of poor dietary intake either alone or in combination with malabsorption or increased utilisation. Excess cell turnover may be physiological such as in pregnancy and lactation or pathological such as in haemolysis or chronic inflammatory disorders. Other causes of folate deficiency include excess urinary loss, drugs, long-term dialysis and alcoholism. While there is no requirement to measure serum folate routinely in pregnancy, testing should be sought in those with a history of poor or inadequate diet, any symptoms of malabsorption and those with an unexplained macrocytic anaemia. Hyperemesis during pregnancy and multiparity are also recognised as risk factors prompting investigation.