Maternal Physiology + Pregnancy Flashcards
Why does the body need to adapt?
Volume support
Nutrition
Waste clearance
Pregnancy maintenance
Childbirth
What drives adaptational changes?
Hormones
Human placental lactogen
Oestrogen
Progesterone
hCG
What is gestational diabetes?
A glucose intolerance that is first recognised in pregnancy + does not persist after delivery
How does gestational diabetes occur?
Resistance to insulin is not met with a compensatory rise in maternal insulin > maternal hyperglycaemia
Adaptations in the respiratory system in pregnancy
tidal volume increases > increases ventilation
What is the clinical consequence of adaptations to respiratory system in pregnancy?
Dyspnoea
(Women may complain of feeling SOB)
Adaptations of the cardiovascular system in pregnancy
- reduced systemic vascular resistance to increased cardiac output by 40%
- increased procoagulants
- decreased anticoagulants ^v (increases clotting)
- reduced fibrinolysis
How does pregnancy cause an increase in cardiac output?
- oestrogen + progesterone cause a drop in BP
- stimulates RAAS
- AngII causes release of aldosterone
- aldosterone stimulates reabsorption at kidneys
- increases plasma volume > increased stroke volume + heart rate > increased cardiac output
What are the clinical consequences of adaptations to CVS in pregnancy?
- peripheral oedema (due to increased RAAS)
- dilutional anaemia (due to increase in plasma volume)
- hyper coagulable state > increased risk of DVT + PE
What is the most common cause of anaemia in pregnancy?
Iron deficiency
What is dilutional anaemia in pregnancy?
Plasma volume increases > dilutes RBCs > anaemia
Complications of anaemia in pregnancy
- increased morbidity for mum + baby
- preterm delivery
- infant iron deficiency anaemia
- maternal fatigue
Adaptations of the renal system in pregnancy
GFR needs to increase to increased clearance
- systemic vasodilation > increased renal blood flow
- decreased PCT absorption
- smooth muscle relaxation > increased size of kidneys + ureters
What is normally seen in U&Es in pregnancy?
Decreased serum urea + creatinine
What effect does the changes in the renal system in pregnancy have?
- increased GFR
- decreased serum urea + creatinine
- glucosuria
- increased risk of UTI
Adaptations in the GI system in pregnancy
slow transit time to increase absorption
- progesterone causes smooth muscle relaxation in GI tract > slow gastric emptying
- nausea, constipation + heart burn
Adaptation of the thyroid in pregnancy
- oestrogen increased liver production of thyroid binding globulin
- causes increase in TSH + thyroxine production
- free levels are unchanged
How are the change in the endocrine system in pregnancy achieved?
Thyroid regulation
Parathyroid activation
Insulin resistance
Changes to calcium metabolism in pregnancy
Why is this needed?
- increased calcitriol
- increased calcium reabsorption in gut
- increased phosphate excretion in kidneys
. - allows for greater calcium availability for fetus > optimal bone growth
What changes to glucose metabolism occurs in pregnancy?
- reduction in maternal blood glucose + aa conc.
- insulin resistance in 2nd half of pregnancy
- increase in maternal free fatty acids, ketone + triglyceride levels (alternative metabolic fuel)
- increased insulin release in response to normal meal
Risk factors of gestational diabetes
- BMI >30kg/m2
- previous macrosomic baby
- previous gestational diabetes
- family history
- ethnicity with high prevalence of diabetes (Asian)
Impact of gestational diabetes on fetus
- Increased birth weight
- Congenital defects especially cardiac, renal, unreal tube defects
- Stillbirth
Investigations of gestational diabetes
Oral glucose tolerance test
Consequences of gestational diabetes to mother
- increased risk of pre-eclampsia, polyhydramnios + premature labour
- shoulder dystocia during labour
- increased risk of developing type 2 DM
Adaptions in the MSK in pregnancy
- change in centre of gravity
- stretching of abdominal muscles
- increased mobility of sacroiliac joint + pubic symphysis
- anterior tilt of pelvis
Complications in neonates of gestational diabetes
Hypoglycaemia
Respiratory distress
Jaundice
Changes in posture in pregnancy due to MSK changes
- forward flexion on neck
- increased lordosis + kyphosis
- impedes postures
Adaptations in the skin in pregnancy
Linea nigra
Vascular spiders
Palmar erythema
Chloasma
What is pre-eclampsia?
Pregnancy induced hypertension with proteinuria +/- maternal organ dysfunction after 20 weeks
Risk factors of pre-eclampsia
- > 40 years
- nulliparity
- pregnancy interval of >10 years
- family history + previous history
- BMI >30kg/m2
- pre-existing vascular or renal disease e.g. hypertension
- multiple pregnancy
How does pre-eclampsia occur?
- placental insufficiency
- impaired invasion of trophoblast > shallow invasion of spiral arteries
- causes hypoperfusion + ischaemia
Presentation of pre-eclampsia
- headache
- visional distubrnace
- epigastric pain
- oedema of hands, feet + hands
- vomiting
- dyspnoea
What is nulliparity?
First pregnancy
Complications of pre-eclampsia in mother
- seizure (eclampsia)
- cerebral haemorrhage
- renal failure
- pulmonary oedema
- HELLP syndrome
- disseminated intravascular coagulation
What is HELLP syndrome?
- Haemolysis
- Elevated Liver enzymes
- Low Platelets
Complications of pre eclampsia in fetus
- growth restrictions
- oligohydramnios
- placental infarct
- renal distress
- premature deliver
- still birth
What is eclampsia?
Seizures
Changes in immunity:
- what does baby need?
- what does mum need?
- how is this achieved?
- baby needs to thrive but as a ‘parasite’
- mum needs to be a good ‘host’
- immune regulation
What adaptations occur within the immune system during pregnancy?
Mother in immunosuppressed state
What does the baby need in regard to the respiratory system?
Oxygen delivery
Carbon dioxide removal
What does mum need in regard to respiratory system during pregnancy?
- continued O2 delivery to her
- increased O2 supply to meet metabolic demand
- increased CO2 clearance
How are the respiration requirements of pregnancy achieved?
Increased ventilation
What does mum need in regard to CVS during pregnancy?
- fill utero-placental-fetal circulation
- oxygenated growing uterus
- protect from impaired venous return
- prepare for possible blood loss during delivery
How are the CVS requirements of pregnancy achieved?
Volume expansion
Clotting mechanisms
