Effect of Pregnancy on Maternal Physiology Flashcards
Which hormone causes softening of the sacral ligaments?
Relaxin
Why do pregnancy women get backache?
Centre of gravity changes developing an accentuated lumbar lordosis
Why may pregnant women get varicose veins?
Pressure on IVC will impede venous return from the lower limbs and may impair function of valves
What is physiological anaemia of pregnancy?
Haematopoiesis increases but increased plasma volume means that red cell count, haematocrit and haemoglobin are all reduced
Why are pregnant women at risk for thromboembolism?
Platlets more reactive and increase in clotting factors
What are the characteristics of uteroplacental circulation?
High volume, low resistance
Why is uteroplacental low resistance?
Spiral arteries and arterioles lose capacity to vasoconstrict
What happens to blood volume in pregnancy?
Reduced TPR triggers RAAS increasing blood volume
What factors contribute to vasodilation in pregnancy resulting in low blood pressure?
Pregnancy hormones suppressing pressor (AT II) agents such as angiotensin
Oestrogen increased VEGF and NO production in endothelial cells
Endothelial cells release prostaclycin
What happens to CO during pregnancy?
Increased by 30-50% during weeks 6-28
Why may pregnant women faint when lying flat?
Uterus obstructs IVC decreasing venous return
What happens to BP in pregnancy?
Normally falls in second trimester
Systolic falls 5-10mmHg and diastolic 10-15mmHg
What changes occur to the respiratory system during pregnancy?
Progesterone increases sensitivity of central CO2 receptors
Increases tidal volume by 4%
Ventilation rate stays the same
Why does renal function increase in pregnancy?
Kidneys need to deal with foetal urea
What changes in Us & Es occur during pregnancy?
Urea, creatinine and uric acid decrease
What happens to GFR during pregnancy?
Increases due to increased cardiac output
Why are pregnant women prone to UTI?
Compression of bladder causes ureters to dilate
How much does total body water increase by in pregnancy?
6-8L
Why does blood osmolality fall in pregnancy?
Decreases urea and creatinine due to increased GFR
What is morning sickness related to?
hCG levels
Why do pregnant women get constipated?
Pressure of uterus on rectum and lower colon
Progesterone relaxes smooth muscle decreasing motility
Why do pregnancy women get gastric reflux?
Pressure of uterus causes relaxation of lower oesophageal sphincter
Why do pregnant women gain weight?
Breast tissue
Foetus
Placenta and amniotic fluid
Fat and extracellular fluid
What metabolic changes occur during early pregnancy?
3kg fat laid down to provide energy during final trimester
Maternal tissue more sensitive to insulin
Increased protein synthesis
What metabolic changes occur during late pregnancy?
Relative insulin resistance
Increased lipolysis to provide energy for mother - increase in TAGs
Increased requirement for protein
What is folic acid required for?
Neural tube fusion
Why should pregnant women not have too much vitamin A?
Can cause foetal abnormalities
Why do calcium levels increase in pregnancy?
Maternal gut absorption increases (vit D3)
Urinary loss decrease (PTH)
Increase in calcium released from bone
Active transport across placenta to calcify skeleton of foetus
Why is zinc important in pregnancy?
Required for metabolic processes e.g. protein synthesis, insulin synthesis
When should iron be given to pregnancy women?
If iron deficiency anaemia is present
What hormones does the mother secrete?
Growth hormone
Prolactin
PTH
Decreased FSH and LH
What is a suggested cause of pre-eclampsia?
Failure of the second wave of trophoblast invasion that normally impairs the spiral arteries ability to constrict
What are the symptoms of pre-eclampsia?
Hypertension
Proteinuria
Oedema
Why does pre-eclampsia cause oedema and proteinuria?
Renal arteriolar endothelial damage from high blood pressure cause proteinuria and oedema
When does pre-eclampsia begin?
20 weeks
What is a complication of pre-eclampsia?
Foetal growth restriction due to reduced perfusion of placenta
What is eclampsia?
Extreme hypertension which increases intracranial pressure leading to seizures, cerebral haemorrhage and coma
What interventions are present for eclampsia?
Magnesium sulphate
Antihypertensives
Rapid delivery
Careful fluid balance
What is gestational diabetes associated with?
Foetal macrosomia - big baby with increased insulin resistance and high glucose
