Anaema during pregnancy

Why Anaemia during Pregnancy is a Concern ?

Amongst all medical disorders and complications anaemia during pregnancy is the commonest medical disorder during pregnancy. Out of estimated 160 million deliveries occurring annually in the world, approx 6,00,000 women die from the complications of pregnancy & child birth. Anaemia is responsible for 40-60% of maternal deaths in developing countries. It also increases perinatal mortality and morbidity rates.

DEFINITION

Anaemia during pergnancy 1
Anaemia during pergnancy 1

Anaemia is a condition of low circulating haemoglobin in which haemoglobin concentration has fallen below the threshold lying at two standard deviations below the median value for a healthy matched population.

W.H.O defines anaemia in pregnancy as haemoglobin concentration of less than 11 g/dl and haematocrit of less than 0.33. The cut-off point suggested by the United States Centers for disease control is 10.5 gm/dl in the second trimester.

SEVERITY OF ANAEMIA

 ICMR describes four grades of anaemia depending upon the haemoglobin levels as shown:

Grades of AnaemiaHaemoglobin Value  (g/dl)
Mild9-10.9
Moderate7-9
Severe< 7
Very Severe< 4

ERYTHROPOIESIS

Erythropoiesis is confined to the bone marrow in adults. RBCs are formed through stages of pro-normoblast – normoblast – reticulocytes – mature non-nucleated erythrocyte. After a life span of 120 days RBCs degenerate and hemoglobin is broken down into haemosiderin and bi-pigment. For proper erythropoiesis adequate nutrients are needed:

  1. Minerals: Iron, traces of copper, cobalt and zinc.
  2. Vitamins: Folic Acid, Vitamin B12, Vitamin C, Pyridoxine and riboflavin
  3. Proteins: For synthesis of globin moiety.
  4. Hormones: Androgens and thyroxine.

ERYTHROPOIETIN

Erythropoietin is a hormone produced by kidneys (90%) and the liver (10%). Increased secretion occurs during pregnancy due to placental lactogen and progestrone.. Eryhtropoietin increases red cell volume by stimulating stem cells in the bone marrow. In addition to common deficiency of folic acid and iron, there is a growing body of evidence to implicate vitamin A in nutritional anaemia.

HAEMATOLOGICAL CHANGES IN PREGNANCY

CharacteristicNormal Adult Women32-34 Weeks GestationIncreased / Decreased
Plasma  volume (ml)260038501250 in
Red cell mass (ml)14001640-1800*Increased
Haemoglobin (g/dl)12-1411-12Decreased
Red Blood Cells (10*6 /mm*3)4-53-4-5Decreased
Packed cell volume0.36-0.440.32-0.36Decreased
Mean corpuscular volume80-9770-95Decreased
Mean corpuscular haemoglobin (pg)27-3326-31Decreased
Mean corpuscular haemoglobin concentration (%)32-3630-35Decreased
Serum Iron (µg/dl)60-17560-75Decreased
Total Iron Binding Capacity (µg/100ml)300-350350-400Increased
Percentage Saturation (%)3015Decreased
Requirements of iron (mg/day)1.5-2.04.0Increased

Mean corpuscular haemoglobin = MCH                                        

Packed cell volume = PCV                     

Mean corpuscular haemoglobin concentration = MCHC                 

Mean corpuscular volume = MCV                                                                                  

Total iron binding capacity = TIBC

PREVALENCE OF ANAEMIA IN PREGNANCY

Overall prevalence is 40% of world’s population. Prevalence of anaemia is 3-4 times higher in developing countries. Average prevalence is 56%. In industrialized countries approx 18% of women are anaemic during pregnancy. In India alone the prevalence of anaemia in pregnancy is as high as 88% (W.H.O Global Database 1997).

CLASSIFICATION OF ANAEMIA IN PREGNANCY

ACQUIRED

  • Iron deficiency anaemia
  • Anaemia caused by blood loss
    • Acute (APH)
    • Chronic (Hook worm infestation, bleeding piles etc.)
  • Megaloblastic anaemia (Vitamin B12 and folic acid deficiency)
  •  Acquired hemolytic anaemia
  •  Aplastic or hypo-plastic anaemia

HERIDITARY

  • Thalassemias
  • Sickle cell haemoglobinopathies
  • Other haemoglobinopathies
  • Hereditary hemolytic anaemias (RBC membrane defects, spherocytosis)

IRON DEFICIENCY ANAEMIA

It is the commonest type of anaemia in pregnancy. Food iron is made up of two pool namely Heam Iron pool and Non-Heam Iron pool

Haem Iron Pool includes all food containing iron as haem molecules, such as animal flesh and viscera. Its absorption is 15-30%, but it can increase to 50% in iron deficiency state. Its absorption is usually not affected by inhibitors.

Non-Haem Iron Pool includes cereals, vegetables, milk and eggs. Its absorption can be increased by enhancers and decreased by inhibitors.

  • Enhancers of absorption: Haem iron, proteins, meat, ascorbic acid, ferrous iron, gastric acidity, alcohol, low iron stores, increased erythropoietic activity.
  • Inhibitors of iron absorption: Phytates, calcium, tannins, tea & coffee.

CAUSES OF INCREASED PREVALENCE OF I.D.A

  • Dietary habits: Consumption of low-bio availability diet
  • Food Fadism
  • Defective iron absorption due to intestinal infections, hook worm infestation, amoebiasis, giardiasis.
  • Increased iron loss: Frequent pregnancies, menorrhagia, hook worm infestation, chronic malaria, excessive sweating, piles.
  • Repeated and closely spaced pregnancies and prolonged period of lactation.

IRON REQUIREMENT IN PREGNANCY

Total iron requirement is 1000 mg.

  • Fetus and placenta — 300 mg
  • Increase  in red cell mass – 500 mg
  • Basal loss – 200 mg

Average requirement is 4-6mg/day.

  • 2.5 mg/day in early pregnancy
  • 5.5 mg/day from 20-32 weeks
  • 6-8 mg/day from 32 weeks onwards

PREVENTION OF IRON DEFICIENCY

  • Prophylaxis of non-pregnant women – 60 mg of elemental iron daily for 3 months.
  • Iron supplementation during pregnancy.
    • Routine iron supplementation is debatable in western countries
    • It has to be given in non-industrialized countries
    • W.H.O RECOMMENDATION: Universal oral iron supplementation for pregnant women (60 mg of elemental iron and 250 µg of folic acid) for 6 months in pregnancy and additional of 3 months post-partum where the prevalence is more than 40%.
    • MINISTRY OF HEALTH, GOVT. OF INDIA RECOMMENDATION:  100 mg of elemental iron with 500 µg of folic acid in second half of pregnancy for atleast 100 days. 2 injections of iron dextran (250 mg each) given IMI at 4 weeks interval with TT injection.
  • Treatment of hook worm infestation
    • Single albendazole (400 mg) or mebendazole (100 mg x BD x 3 days)
    • Change in defecation habits and avoidance of walking bare footed.
  • Improvement of dietary habits and improving bio availability of food iron
  • Iron fortification of food.

EFFECTS OF ANAEMIA ON PREGNANCY

 Maternal effects

ANTENATALINTRANATALPOST NATAL
Poor weight gainDysfunctional labourPuerperal Sepsis
Preterm labourHaemorrhage & shockSub-involution
Pre=eclampsiaCardiac failureEmbolism
Abrupto placentae
Inter current infections
PROM

Fetal effects

  • Risk of pre-maturity
    • IUGR, LBW, poor apgar score
    • Depleted iron store in neonates and anaemia in infancy period
    • High prevalence of failure to thrive and poor intellectual development.
    • Cardiovascular morbidity and mortality in adult lives

INVESTIGATIONS

  • Haemoglobin estimation
  • Peripheral blood smear – microcytosis, hypochromia anisocytosis, poykilocytosis and target cells
  • RBC indices – Decreased MCV, decresed MCH, decreased MCHC, MCV is the most sensitive indicator
  • Decresed serum ferritin – first abnormal laboratory test
  • Decreased transferrin saturation – second to be affected
  • Increased  FEP – third test to become abnormal
  • Increased serum transferrin receptor – best indicator
  • Bone marrow examination  –  no response to treatment after 4 weeks of therapy
    • Aplastic anaemia
    • Diagnosis of kala-azar
    • Urine examination
    • Stool examination – for three consecutive days
    • Other tests – RFT, LFT, TSP A:G, chest x-ray, sputum examination, etc.
    • For response – haemoglobin and PBS, reticulocyte count

MANAGEMENT OF IRON DEFICIENCY ANAEMIA

AIM

  • To correct iron deficiency
  • To restore iron reserve
  • To correct associated complicating factor

CHOICE OF THERAPY

  • Depends on severity of anaemia
  • Duration of pregnancy
  • Associated complicating factor

GENERAL TREATMENT

  • Dietary advice
  • Treatment of associated complicating factor

IRON THERAPY

  • Oral
  • Parenteral
ORAL IRON THERAPY
  • For women presents in mid trimester or early third trimester
  • For treatment more than 180 mg of elemental iron/day is required
  • To minimize side effects, start with low dose
  • Treatment is continued till blood picture becomes normal, thereafter maintenance of one tablet daily for 3 months to replenish iron stores
Indications of response to therapy
  • Sense of well being
  • Improved outlook of patient
  • Increased appetite
  • Incresed haemoglobin, haematocrit, reticulocytosis within 5-10 days
  • If no significant clinical or haematological improvement within 3 weeks, diagnostic re-evaluation is needed.
Rate of improvement:

After a lapse of few days haemoglobin concentration is expected to rise at a rate of 0.7 g/dl/week.

Causes of failure of oral therapy
  • Incorrect diagnosis
    • Malabsorption syndrome
    • Presence of chronic infection
    • Continuous loss of iron
    • Poor patient compliance
    • Concomitant folate deficiency.
PARENTRAL IRON THERAPY
Indications:
  • In tolerance to oral iron
  • Poor patient compliance
  • Unpredictable absorption
  • Patient near term
Advantage
  • No added advantage over oral iron except for certainty of its administration.
  • Intra muscular
  • Intra venous
  • Two preparations  –  Iron dextran – IM/IV
  • Iron sorbitol citrate – IM
Iron deficit

Elemental iron needed (mg) = (Normal Hb – Patient’s Hb) x Weight (kg) x 2.21 + 1000

Simple method is to give 250 mg elemental iron for each gm of haemoglobin below normal. Another 50 % is to be added to replenish store. Oral Iron should be stopped atleast 24 hrs prior to therapy to avoid toxic reaction. Iron injections are given daily or on alternate day by deep IMI using ‘Z’ technique.

I.V. route

  Total dose in fusion (TDI) – Dose calculated by same formula

Pre-requisites for TDI:

  • Correct diagnosis of iron deficiency anaemia.
  • Adequate supervision in hospital setting.
  • Facility for management of anaphylactic reaction.
  • Sensitivity test done by 1ml test dose prior to infusion:
  • If no reaction iron dextran is diluted in normal saline or 5% dextrose and given over 4-6 hrs.
  • If total dose is more than 2500 mg infusion is given in 2 doses on consecutive days.
  •  Look for reaction – Chest pain, rigor chills, hypotension, dyspnoea, haemolysis & anaphylactic reaction.
Indication of blood transfusion
  • Severe anaemia beyond 36 weeks
  • Refractory anaemia
  • To correct anaemia due to blood loss
  • Associated infection

MANAGEMENT DURING LABOUR

  • Iron and folate therapy for 3 months
  • Infection if any should be treated energetically
  • Careful watch for puerperal sepsis, failing lactation; sub involution of uterus and thromboembolism
  • First stage – Comfortable position
    • Adequate analgesia
    • Arrangement for oxygen,
    • Digitalization maybe required in cardiac failure due to severe anaemia
    • Antibiotic prophylaxis
  • Second stage – Cut short by forceps application.
  • Active management of third stage
  • During puerperium
    • Adequate rest
    • Iron and folate therapy for 3 months
    • Infection if any should be treated energetically
    • Careful watch for puerperal sepsis, failing lactation; sub involution of uterus and thromboembolism

Video

Shoot your thoughts in the comments below.

You can consult with us. Book an Appointment with our expert dietitians.

For more details you can follow us on Facebook, Twitter & Instagram.

Support and share
0 0 votes
Article Rating
Subscribe
Notify of
guest
1 Comment
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
trackback

[…] reduces the risk of premature birth and low birth weight. Not getting enough iron could cause anaemia. Iron deficiency could contribute to developmental delays and behavioral disturbances in the infant […]

1
0
Would love your thoughts, please comment.x
()
x