physiology of pregnancy and labour Flashcards
how does hypertension happen in pregnancy
CRH makes ACTH which makes aldosterone
how does insulin resistance and oedema happen in pregnancy
CRH makes ACTH which makes cortisol
what is normal pregnancy HR
90
blood pressure changes during pregnancy and in multiple pregnancies
drops during 2nd trimester (uteroplacental circulation expands & peripheral resistance decreases) then rises back in third
Mutiple pregnancy – CO increases more, BP drops more
CO during pregnancy and labour
increases 30-50% in pregnancy and extra 30% in labour
Physiological ECG changes
Palpitations normal but with dizziness or sob then may be abnormal
Slight left axis deviation
Inverted or flattened T-waves (Leads III, V1-V3)
Q-wave (Leads II, III, aVF)
Atrial and ventricular ectopic beats more common
Haematological changes
plasma volume increases proportionally with Cardiac output
erythropoesis (RBC) increases
Hb is decreased by dilution (this decreases blood viscosity).
Iron requirements increases (6-7mg/day in 2nd half of pregnancy)
anaemia in pregnancy
first trimester Hb <110g/L
2nd and 3rd trimester Hb <105g/L
Postnatal Hb <100 g/L
(Out-with pregnancy normal Hb 120-160g/L)
Average bloodloss at birth
<500ml
Changes to maternal coagulation
Hypercoagulable state
Reduces risk of haemorrhage during and after delivery
Increased risk venous thromboembolism
Postpartum Haemorrhage
treatment
Tranexamic acid
Transfusion 4xRBC
Consider FFP >2000ml or coagulopathy
urinary system changes
increase in renal blood flow= increased GFR= pee more
dilatation of collecting system and ureters = increased risk of urine infection
bladder and urethra elevated and stretched= urinary incontinence
reduced bladder tone and sensation= urinary retention
average maternal weight gain
11kg
fetus= 3.5
nutrition
extra 200cal
extra 30g/ day
