8. Maternal Physiology Flashcards
What are the main broad reasons why the body needs to adapt in pregnancy?
Volume support Nutrition Waste clearance Pregnancy maintenance Childbirth
What drives the adaptations in pregnancy?
Hormones - hCG, oestrogen, progesterone, relaxin, hPL
How does the mother adapt to changes in respiration levels?
Increased ventilation
TV increase - increase PaO2, decrease pCO2
ERV decrease
TLC decrease due to elevation of diaphragm
Dyspnoea may occur
How does the mother adapt to cardiovascular and haematology needs of pregnancy?
Volume expansion
Clotting mechanisms
How does volume expansion occur in the mother?
Early - increased volume
Late - increased HR (98bpm)
Progesterone - smooth muscle relaxation (decrease SVR, drop in BP)
How does clotting increase in the mother?
Increased procoagulants (fibrinogen, factor VIII, vWF) Decreased anticoagulants (protein S) Reduced fibrinolysis
How does the mother increase stroke volume?
Oestrogen and progesterone stimulate RAAS system
Increased angiotensinogen from liver stimulated by oestrogen
No vasoconstriction
What are some consequences of adaptations of CVS in pregnancy?
Increased RAAS - leads to peripheral oedema
Change in plasma volume, changes RBC volume - leading to dilutional anaemia
Clotting - hypercoagulable state, increased number of thromboembolic events
How does the mother adapt to increased demand of renal system?
Increased GFR
What are the adaptations of the renal/urinary system in the mother?
Systemic vasodilation- increased RBF, increased GFR, decrease serum urea and creatinine
Decreased PCT absorption - glucosuria
Smooth muscle relaxation and obstruction - increased size of kidneys and ureters, decreased speed of urine passage
How does the GI system adapt in pregnancy?
Slows transit time to increase absorption of nutrients
What are the adaptations in the GI tract in pregnancy?
Structural - uterus displaces bowel, can cause mechanical obstruction LFTs - ALP levels increase Decreased LOS tone Decreased small bowel motility Decreased large bowel motility Decreased gallbladder contractility
What are some consequences of the changes in the GI system in pregnancy?
GORD, aspiration
Constipation
Gallstones
How does the mothers endocrine system adapt?
Thyroid regulation
Parathyroid activation
Insulin resistance
What are the changes in MSK and skin in pregnancy?
Make everything loose and stretchy
What are the MSK adaptations in the mother?
Change in centre of gravity - increased lordosis and kyphosis, forward flexion of neck
Stretching of abdominal muscles - impede posture, strain paraspinal muscles
Increased motility of sacroiliac joints and pubic symphysis, anterior tilt of pelvis
What are the changes in skin in pregnancy?
Chloasma
Palmar erythema
Vascular spiders
Linea nigra
What is pre-eclampsia?
Hypertension and proteinuria
What are the risk factors for pre-eclampsia?
Chronic or gestational HTN Pre-existing renal disease Diabetes Obesity Family history First pregnancy Extreme stress of age IVF
What is the pathology in pre-eclampsia?
Impaired invasion of trophoblast leading to shallow invasion of spiral arteries
Leads to hypoperfusion and ischaemia - systemic endothelial dysfunction
What are the signs and symptoms of mild pre-eclampsia?
Elevated blood pressure
Elevated protein in urine
Weight gain exceeding 2lbs per week
Water retention and swelling
What are the signs and symptoms of severe pre-eclampsia?
Headaches
Changes in vision
Nausea/vomiting
Pain in abdomen and back
What are the maternal complications of pre-eclampsia?
Seizure Cerebral haemorrhage Renal failure Pulmonary oedema DIC and thrombocytopenia Haptic failure or rupture
What are the fetal complications in pre-eclampsia?
Growth restriction Oligohydramnios Placental infarct or abruption Fetal distress Premature delivery Stillbirth
