the low down on anaemia in pregnancy
DESCRIPTION
An outline on how to approach the problem of pregnancy anaemia from a clinical standpoint. Specially presented for the benefit of students and primary care physicians.TRANSCRIPT
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HERE’S A LOW DOWN
ON ANAEMIA IN PREGNANCY
brought to you by
Associate Professor Dr Hanifullah Khan
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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
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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
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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
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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
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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
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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
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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
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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
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This explains the risks of being pregnant with anaemia
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Why should anaemia be avoided in pregnancy?
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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
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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
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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
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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
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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
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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
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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!
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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
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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
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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
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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?
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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
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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
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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