PHYSIOLOGICAL HAEMATOLOGICAL CHANGES IN PREGNANCY

-Akshay.b.k

BLOOD VOLUME :

• During pregnancy there is increased vascularity of uterus with the interposition of utero placental circulation, leading to increased circulatory demand.

• Therefore there is progressive and inconsistent rise in blood volume.

• It starts to increase by about 6th week of pregnancy to about 40-50% (5500ml) above the non-pregnant level at around 30-32 weeks.

PLASMA VOLUME :

• It starts to increase by 6 weeks and plateaus

at 30 weeks of gestation.

• Total plasma volume increases to the extent of 1.25lts( i.e. from 2500ml to 3750ml).

• The increase is greater in multigravida, in multiple pregnancy, with large baby.

RBC & HAEMOGLOBIN :

• The RBC mass is increased to the extent of 20-30% (i.e. 350ml).

• The increase is regulated by the increased demand of O2 transport during pregnancy.

• RBC mass begins to increase by 10 weeks and continues till term.

• Iron supplementation increases it by 30%.• This disproportionate increase in plasma & RBC

volume produces haemodilution (i.e fall in PCV).

LEUCOCYTES & IMMUNE SYSTEM:

• Neutrophilic leucocytosis occurs to the extent of 10 -15000/cu.mm and even to 20000/cu.mm during labour.

• Increase is due to rise in oestrogen and cortisol levels.

• Major change in immune system is modulation away from cell-mediated immune response towards increased humoral and innate immunity.

TOTAL PROTEIN & BLOOD COAGULATION FACTORS:

• Total plasma protein increases from normal 180gm to 230gm at term.

• Due to haemodilution plasma protein conc falls, leading to decrease in viscosity of blood.

• A:G OF 1.7:1 is diminished to 1:1• Pregnancy is a hypercoagulable state ,fibrinogen level

raises from 200-400mg/dl to 300-600mg/dl.• ESR is increased (4 fold).• Increased activity of clotting factors I,VII,VIII,IX,X.

Conclusion ( principal blood changes in pregnancy ) :parameters NON-PREGNANT PREGNANCY(term

) CHANGE

BLOOD VOL (ml) 4000 5500 1500

PLASMA VOL (ml) 2500 3750 1250

RBC VOL (ml) 1400 1750 350

TOTAL Hb (gm) 475 560 85

TOTAL PROTEIN (gm)

180 230 50

PLASMA PROTEIN (gm/100ml)

7 6

FIBRINOGEN-mg% 200-400 300-600 +50%

ESR (mm/hr) 10 40 4 fold

THANK YOU….