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HERE’S A LOW DOWN

ON ANAEMIA IN PREGNANCY

brought to you by

Associate Professor Dr Hanifullah Khan

Objectives of this presentation

• To define & classify anaemia in pregnancy

• To highlight the importance of anaemia in pregnancy

• To clinically identify anaemia in pregnancy

• To outline the management

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A reduction in circulating Hb mass below the critical level can be

caused by multiparity

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Definition of anaemia

Definition • A reduction in circulating Hb mass below the

critical level

• Normal Hb between 12-14g%

• WHO has accepted up to 11g% as normal

• However in many developing countries the lower limit is often accepted as 10g%

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WHO 2007

Definition -trimester specific

• Haemoglobin level :

1st Trimester : < 11g/dL

2nd Trimester : < 10.5 g/dL

3rd Trimester : < 11g/dL

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Haematological changes in pregnancy

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Physiology

Physiology

• Haematological changes in pregnancy - geared towards maternal & feral well-being, especially during delivery

• Physiological changes - raised serum transferrin & Fe binding capacity

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Iron

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• Pregnancy - additional demand of 1000 mg of iron

• Entering pregnancy with low maternal iron stores - anaemia

Fe supplementation may have to be instituted

= 300 mg FeSO4 / 60mg elemental Fe

daily

Anemia resulting from inadequate iron supplementation may result in obstetric complications like preterm

delivery and late miscarriages

Tan EK, Tan EL. Best Practice & Research Clin Obstet Gynaecol 2013

Plasma volume• Plasma volume increases 30–50% in pregnancy

about 1200–1300 mls

• This increase is higher in

Multigravidas

Twin pregnancy - can be as high as 70%

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Tan EK, Tan EL. Best Practice & Research Clin Obstet Gynaecol 2013

Blood volume• Increased volume necessary

to allow for increased blood flow to organs (uterus, kidney)

to counter blood loss at delivery

• Beginning 7/52, peak increase around 30-34/52

• At its maximum, intravascular volume is increased to about 45% above normal levels = 1-2 L extra

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Tan EK, Tan EL. Best Practice & Research Clin Obstet Gynaecol 2013

RBCs• Increased RBC production (by erythropoietin)

• 18-25% rise above non-pregnant levels

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Both plasma and red cell mass !are increased in pregnancy

Tan EK, Tan EL. Best Practice & Research Clin Obstet Gynaecol 2013

Dilutional anaemia

The disproportionate increase results in a falling Hb as pregnancy advances

anaemia most noticeable 30-34/52

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Increase in blood componentsRBCs increase

18-25%Plasma vol. increase

30-50%

Haematocrit also falls - decreased blood viscosity Necessary to allow for easier blood flow

This explains the risks of being pregnant with anaemia

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Why should anaemia be avoided in pregnancy?

Summary  of  complica.ons

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Complica)ons

• Maternal

è Inability  to  withstand          haemorrhage  è  Risk  of  PPH

è Risk  of  Infec)on  è Risk  of  cardiac  failure

• Fetal

!è Hypoxia  è IUGR    è Spontaneous  abor)on  è Cogni)ve  delay  

Nur Filzah, Toh Yee Shih, Beatrice Leong. CUCMS 2012

Maternal risks• During Antenatal period –

Poor weight gain, Preterm labour, PIH, placenta previa, APH, eclampsia, PROM

• During labour –

Dysfunctional labour, PPH, shock, anesthesia risk, cardiac failure

• Maternal risk during postnatal period –

Postnatal sepsis, sub involution, embolism

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Fetal/Neonatal Risks• Complications include

Prematurity, low birth weight, poor Apgar score, fetal distress, neonatal distress requiring prolonged resuscitation & neonatal anemia

• Infants with anemia have

Higher prevalence of failure to thrive, poorer intellectual developmental milestones, and higher rates of morbidities and neonatal mortalities than infants without anemia.

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Basic division of the causes of anaemia

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Classification

Summary  of  causes  of  anaemia

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Causes

Excessive  RBC  Loss

Blood  Loss placenta  praevia  abrup.on  prior  menorrhagia

Increased  RBC  destruc)on  (haemolysis)  extrinsic  -­‐  Infec.on,  medica.ons  in.nsic  -­‐  thalassaemia

Inadequate  RBC  Produc)on

iron  deficiency  folic  Acid  deficiency  anaemia  of  chronic  disease  thalassemia

Physiological anaemia

Blood lossBlood loss leading to anaemia

may occur in the index pregnancy or in the past

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Current pregnancy • Placenta praevia is the most obvious &

dramatic cause during the pregnancy

• Concealed abruptio may also be a causeIn the past

• Inability to recover from recurrent blood loss is a consequence of poor pregnancy spacing

• PPH - anaemia in a subsequent pregnancy

• Previous abortions

• Going into pregnancy with a prior history of menorrhagia is another cause

Other causes

• GIT blood loss - ulcer disease or drug induced

• Haemorrhoids

• Worm infestation (Hookworm)

• Trauma

Increased destruction of RBCs

• RBC destruction is called haemolysis - this may occur intra- or extravascularly

• haemolytic anaemia can also be inherited or acquired

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Common causes & Type of haemolytic anaemia in pregnancy

Condition TypeThalassemia

inheritedG6PD deficiency

Pre-eclampsia

acquired

Hepatitis

Blood transfusion

NSAIDs

Malaria

Decreased production of RBCs

• This may result either from a lack of a necessary component or defective stem cell production

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Common causes & RBC features

Condition RBCs

Fe deficiencymicrocytic,

hypochromicChronic diseases

Thalassemia

Vitamin B12 deficiency megaloblastic

Nutritional anaemia is one of the most common causes

Nutritional • One of the most common causes of anaemia

Poor dietary intake or malabsorption causes this

• Mainly due to iron & folate deficit. B12 deficiency is rare in pregnancy

• Folate requirement increased 2x in pregnancy - normal body stores only last 4 months

Folate deficiency exacerbated by haemolysis - e.g. in thalassaemia, malaria

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Nutritional Anaemia i. Iron deficiency

ii. Folate deficiency iii. B12 deficiency

Bone marrow failure

In cases of anaemia, taking a detailed dietary history is very important!

Nutritional anaemia - Fe deficiency• Fe deficiency - the commonest

cause of nutritional anaemia

usually as a result of poor diet

Sources of iron - meat (liver in particular), vegetables, dairy products

• Fe demand increases in pregnancy - about 1g of iron required during a normal pregnancy

1. Anaemia occurs because

2. depleted iron stores because of poor diet

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H o o k w o r m i n f e s t a t i o n i s another cause of i ron defic iency anaemia in the tropics

Physiological anaemia• A state of haemodilution - due to the greater

increase in plasma volume compared to red cells

• êHct & êHb

• Peripheral blood - normochromic and normocytic red cells

• Physiological haematological changes require ≅ 3/52 post-delivery to revert to normal

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How dilution anaemia comes about

• A disproportionate increase of plasma volume during pregnancy

Leading to apparent reduction of RBC, Hb & haematocrit value

• Hb is consequently reduced

• The dilution picture is normochromic & normocytic

This is the so called physiological anaemia

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Graphical presentation of haematological changes in pregnancy

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Ͳ20

-10

0

10

20

30

40

50

PlasmaVolumeBloodVolumeRed CellmassHaematocrit

Weeks of pregnancy

10 20 30 40

C h a n g e (%)

Oliver E, Olufunto K. www.intechopen.com

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How do we identify anaemia in clinical practice

Strategy for assessment• When faced with a patient with anaemia in

pregnancy, the investigation begins with

the taking of a detailed history

a relevant physical examination

concludes with the appropriate investigations

• It is necessary to determine causal factors prior to initiating treatment

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History

In the beginning…• Begin history taking by having a list of possible causes in mind

This list will guide the investigator on the important questions to ask the patient

• Include symptoms of anaemia, their severity and features of complications, and include questions of possible aetiologies

• Since nutritional anaemia is widely prevalent, all patients have also to be investigated in detail on their diet, habits and lifestyle

Not only do we need to know the foods that the patient eats, but also those that she avoids

• It is not uncommon for anaemic mothers to have more than 1 cause for her problem, especially so where nutrition is concerned

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Presentations

• Many patients are asymptomatic

Most commonly, anaemia is identified from routine antenatal testing

• If they are symptomatic, then this usually means that the anaemia is not mild

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What are you thinking?• This G3 P2 was noted to have

an Hb of 10 g% at 32 weeks gestation

• She is now being investigated managed for anaemia in pregnancy

• Hb on booking at 9 weeks was 12.1 g%

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What do you think?

Patients with low Hb on booking

• Important to be aware of physiological anaemia

• Late booking blood may show haemodilution when in fact there is no anaemia

• The best Hb reading is one taken prepregnancy

• The next best alternative is an early pregnancy one

Prior to the entrenched haematological changes

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Symptomatic patients• Many of the symptoms of

anaemia are non-specific

Fatigue, weakness, dyspnoea

Headache, syncope attack

Palpitation, reduce effort tolerance

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The differential diagnoses !

in such patients include:!

!• Cardiac disease • Respiratory distress • Anxiety & Anxiety disorders • Gastric symptoms • Anaemia

• Notice that these are very similar to symptoms caused by other conditions

Prepregnancy anaemia

• Duration of the complaints - establish clearly if they were present before this pregnancy

• Any past history of haematinics prescription and blood transfusions indicates a preexisting condition

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History of haemorrhage• Any haemorrhage? – ante, intra, and post

• Past treatment of anaemia must be sought during these times

• Miscarriages and past menstrual loss - can be associated with significant amounts of bleeding

• A common non-reproductive source of bleeding is the gastrointestinal tract

Passage of black, tarry stools, use of analgesic drugs (NSAIDs), history of peptic ulcer disease

• Dark-coloured urine & yellowness of the eyes - indicate haemolysis

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Chronic Fe depletion

• Multiparous patients - frequent, poorly spaced pregnancies might indicate an inability to adequately recover from delivery blood loss

• Medical histories, including medications used, may suggest a premorbid condition

e.g.the use of anticoagulant medication in cardiac disorders

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Family & Heredity• Family members - any with blood disorders?

• Genetic preponderance suggested by - easy bleeding, anaemia in pregnancy, splenectomy, jaundice and gallstones

• Rare conditions such as thrombocytopaenia, bleeding disorders & collagen disease - gum bleeding, easy bruising, joint pains & skin & facial rashes

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Physical examination

Aims of examination

• Confirm the presence of anaemia

• The extent of the anaemia

• Look for evidence of possible causes.

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General examination

• General inspection - note body habitus

• See if the patient is comfortable

• If she needs to be propped up - might suggest decompensation

• Check BP

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Mucosa & others• Check for pallor & jaundice

• jaundice could be an indicator of haemolysis

• Angular cheilosis, palmar erythema & koilonychia suggest chronic anaemia and malnourishment

• Leg edema - if severe suggests cardiac decompensation (has to be differentiated from pregnancy edema)

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Signs of haemolytic anaemia

• jaundice

• heart murmur

• increased heart rate

• enlarged spleen

• enlarged liver

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Other systems

• Cardiovascular & respiratory system assessment - to rule out decompensation & concurrent disease

• Chronic anaemia may lead to bounding pulses, cardiomegaly and systolic murmurs

• Rounding off the abdominal examination is the search for liver and spleen enlargement

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Uterus

• Establish fetal well-being

• Maternal anaemia, if severe, can lead to fetal growth restriction

A uterus that is smaller than dates

Oligohydramnios

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Investigations

Many clinicians tend to order investigations in a

blunderbuss manner

Investigations for anaemia may be divided into basic &

specific

It is more appropriate to think & order the relevant

investigations

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Basic investigations - FBC

• A full blood count (FBC)

Hb, WBC, platelet counts PCV

• Red cell indices - size and colour

MCV, MCHC, MCH - small (microcytic), normal (normocytic) or large (macrocytic) sized and if they are of normal colour (normochromic) or pale (hypochromic)

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Basic investigations - PBF

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Specific investigations

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Thank you