Anaemia in pregnancy Flashcards
Haemodynamic changes in Pregnancy
Red cell mass increases 18-25%
Plasma volume increases 44-55%
Due to haemodilution there is apparent anaemia
Also–> WBC up, platelets down 20-36 weeks, increased factors VII/VIII+X, ESR and fibrinogen
Changes in Iron metabolism in pregnancy
Increased demands from fetus – MET by –>
Increased Iron absorption –> dietary issues
Mobilization of iron resources –> dangerous if depleted pre-pregnancy (menorrhagia, short interval from last pregnancy or parasitic infections)
Role of Folic Acid in pregnancy
Increased demand for DNA production and growth from the uterus, placenta and fetus –> deficiency linked to neural tube defects
0.5mg daily to 12 wks, 5mg for rest of pregnancy
Definition of Anaemia in pregnancy
NICE and WHO agree:
Over 12 weeks –> 110g/L or less
28 to 30 weeks –> 105g/L or less
Postpartum —> <100g/L
Risks of Anaemia in pregnancy
Maternal –> tiredness and SOB, increased risk of haemorrhage
Fetal –> increased risk of poor outcomes and complications
Types of Anaemia
Microcytic –> Iron deficiency
Macrocytic–> Folate or B12 deficiency
Hereditary –> Sickle cell (trait;SC, homozygous SS) + thalassaemias
Screening for anaemia in pregnancy
Hb and Haemoglobinopathy screen at 12 week
28-30 wks recheck haemoglobin
If Hb is low investigate and give iron supplements
Iron Deficiency Anaemia
50% of women in world and 20% in first world
Aim for 10g increase/wk–> recheck after 4 wks
Increases haemocrit slightly at all points but mostly in the 3rd trimester
If not anaemic only give in multiple pregnancies
Oral Iron
Ferrous sulphate 200mg up to TDS
SEs–> 30% GI upset (vomiting or constipation)
treat by reducing dose or changing formulation (liquid, have with meals etc
Haem-iron and non-haem iron stores in food
Other Treatments for IDA
Parental iron –> IM (pain and discolouration) or IV (anaphylaxis)
Transfusions –> infection, transfusion reaction
Consider if high risk (placenta previa)
Folate deficiency anaemia
Rarer –> epileptics, alcoholics, haemolytic anaemia or drugs (azathioprine)
Confirm with red cell folate –> treat with folate 5mg daily
B12 Deficiency
Rare and usually due to pernicious anaemia which predates pregnancy
Strict vegans
treat with B12 supplementation
Hereditary Anaemias
Sickle is most common–> if mother is carrier check partner
Offer CVS/amnio
Sickle Cell disease in pregnancy
increased risk of Sickle crises (occur in 35% of pregnancies) –> preinatal mortality up 4-6x due to IGUR, preterm labour & fetal distress
Increased maternal mortality –> PET, VTE, infections, high CS rate
Mangement of Sickle cell in pregnancy
Manage crises as if non-pregnant
treat with folate and regular USS to check fetus
Peripartum–> LSCS if indicated, CTG, hydrate mother, analgesia
Thrombocytopenia
Occurs in 5-10% of women at term--> 75% gestational, can be immune or DIC, rarely is SLE, HIV, haemolytic uraemic syndrome If ITP (will predate pregnancy)
Management of thrombocytopenia
Gestational is benign–> normal plts at booking
–> treat symptomatically or prophylatically if persistent check autoantibodies, exclude other causes
Can cause bleeding, antiplatelet IgG can cross placenta –>2% will have fetal problem
–> avoid instruments or FBS, check cord blood
Rhesus Genes
Rhesus group is c,d & e. Rh+ve must be D positive and can be CDE, CDe, cDE, cDe
cde is negative
Rhesus Disease
An Immune-haemolytic anaemia of the fetus
Causes fetal mortality and morbidity
If survives causes prematurity, anaemia and jaudice
Other Blood antibodies
There are 100 RBC antigens, 30 can cause fetal haemolytic disease, Anti-D is 98%
Can also be other rhesus antigens (C or E), Kell, Duffy or Kidd
Sensitising Events for Rhesus disease
Fetomaternal Haemorrhage Early pregnancy loss or bleeding Invasive procedures Antepartum Haemorrhage Labour and delivery
Anti-D
1st trimester–> all operations (ectopic/ERPC/TOP)
2nd trimester–>miscarriage(threatened),CVS/amino
–> 250iu of anti-D
3rd trimester all Rh-ve women get 500iu of anti-D
Kleihauer test
Measures the size of FMH –> uses acid which fetal cells are more tolerant of
500iu of anti-D protects against 4ml of FMH
Current rate of sensitization
~1%
Due to incompatible transfusions
Or mismanagement of previous pregnancies–> Anti-D not given or not enough, spontaneous fetomaternal haemorrhage (FMH)
Management of sensitised women
If untreated–> 50% of infants will have none to mild anaemia, 25% will have moderate anaemia, 25% will develop hydrops
With Transfusion there is >80% survival
Risks–>Cord tamponade, haemorrhage or miscarriage
Neonatal problems related to rhesus disease
Major risk is prematurity
If Anaemic transfuse Rhesus negative blood
Haemolysis of RBCs can lead to jaudice–> treat with phototherapy or exchange transfusions
Prevalence of Anaemia in pregnancy
Overall 40% of the world
56% in developing countries and 18% in developed countries
Causes of Anaemia in pregnancy
Deficiency - reduced production or increased loss of RBCs
Haemodilution –> plasma volume increases disproportionately
Symptoms of anaemia in pregnancy
Most commonly: Tiredness, Lethargy & SOB
Less commonly: headache, tinnitus, altered sense of taste, sore tongue, feeling itchy
Pica (the desire to eat non-food items, paper/clay etc)
Maternal risks from anaemia
Poor weight gain, Preterm labour, PE, abruption, Haemorrhage/shock, PPH, sepsis
Fetal risks from anaemia
Risk of prematurity, IUGR or low birth weight, anaemia in infancy, Failure to thrive and poor intellectual development
Inhibitors and Enhancers of iron absorption
Inhibitors–> phytates, tannins,Ca, tea & coffee
Enhancers –> haem iron, proteins, meat, ascorbic acid, gastric acidity and alcohol
Haem iron versus non-haem iron
Haem iron is in the haem molecule so found in meat, while non-haem iron is in eggs and cereal etc
