Lecture 15 - Maternal Physiology Flashcards
What are some hormones that drive the physiological adaptations seen during pregnancy?
HCG
Oestrogen
Progesterone
Relaxin
hPL (Human Placental Lactogen)
What produces the hormones that drive the physiological adaptations seen in pregnancy?
Corpus luteum
Placenta
How does the immune system change during pregnancy?
Immunosuppressed state
Since the fetus is half paternal/foreign
What changes in respiration need to occur during pregnancy?
Increased O2 supply
Increased CO2 clearance
So increased ventilation
What lung volumes/capacities change during pregnancy and why?
Tidal Volume increases
Expiratory Reserve Volume and Total Lung Capacity decrease since the uterus compresses the diaphragm
What affect on the body does increasing Tidal volume have?
Inc PaO2 + Dec PCO2
Resp alkalosis (gets compensated by renal bicarb)
What is Dyspnea of Pregnancy?
The feeling of shortness of breath during pregnancy but not actually increasing respiratory rate
What are some pathological issues that may actually lead to shortness of breath and not be the normal Dyspnea of pregnancy?
Cardiac issues
Anemia
DVT/PE
Asthma
Pneumonia/ARDS
Pulmonary oedema
What does mom need to do to ensure baby receives all of the nutrients it needs?
Increase volume of circulation/delivery
Prepare for potential blood loss during delivery
Volume expansion
Inc clotting mechanisms
How does the mother increase blood delivery?
Increase Cardiac output
Reduce systemic vascular resistance
What is the equation for cardiac output?
CO = Heart rate x Stroke volume
How is cardiac output increased during pregnancy?
Inc SV (inc blood volume)
+
Inc HR
What leads to the reduced systemic vascular resistance in pregnancy?
Progesterone being produced relaxes smooth muscle leading to vasodilation
What substances increase in the blood leading to increased clotting?
Increased procoagulants
Decreased anticoagulants
Reduced fibrinolysis
How is Sv increased in pregnancy?
Oestrogen and progesterone causes peripheral vasodilation
This leads to RAAS activation due to drop in BP
This leads increased fluid volume increasing SV.
What negative effect often happens as a result of RAAS system activation in pregancy?
Peripheral oedema (ankle swelling)
Dilutional anaemia
Why does dilutional anemia occur in pregnancy?
The increase in plasma volume is much more than the increase in RBC number
What is a pregnant woman at increased risk of due to being in a hypercoagulable state?
DVT
PE
What is the most common cause of anaemia in pregnancy?
Iron deficiency anaemia
How does iron deficieny anaemia usually affect the size of RBCs?
How can this be different in pregnancy?
Iron deficiency anamiea (normally) = Microcytic
Iron deficieny anaemia in pregancy = can be Normocytic or Macrocytic
How can Hb levels differ in pregnancy to normal?
Can be slightly lower than the normal range and be ok
What are some complications of anaemia of pregnancy?
Inc morbidity for mom andn baby (baby not getting enough O2)
Preterm delivery
Maternal fatigue
Infant iron deficieny anaemia
What changes need to occur in the mother’s renal system and why?
Increase GFR
Need to increase the clearance of wastes
How is GFR increased during pregnancy?
How are serum urea and creatinine levels affectd?
Systemic vasodilation due to progesterone production
This increases renal blood flow whihc increases GFR
Creatinine and urea levels in serum decreased (in urine increased)
How is absorption in the PCT affected during pregnancy?
What affect does this have?
Decreased PCT absorption
Get glucosuria due to lower glucose threshold
What happens to the kidneys and ureters in pregnancy and why?
What does this increase the risk of?
Smooth muscles relax due to progesterone
Stasis of urine can occur which can lead to hydroureter and hydronephrosis and increased UTI risk
What changes occur in the mother’s GI system in pregancy and why?
Transit time in gut is slower
This is to increase/maximise the absorption of nutrients like vitamins and minerals
What are some symptoms that a pregnant lady can expierence related to the GI tract?
GORD (decreased Lower oesophageal tone due to progesterone)
Constipation (slower transit time)
Gallstones (decreased gall bladder contractility)
How can constipation occur in a pregnant woman that isn’t caused by slower transit time?
The uterus can displace the bowel causing a mechanical obstruction
How many LFTs be affected in pregnancy and why?
ALP levels increased due to placental synthesis
What endocrine changes need to happen to ensure mother can give baby glucose and lots of calcium while keeping metabolism under control?
Thyroid regulation
Parathyroid activation
Insulin resistance
What affect does oestrogen have on the thyroid in pregancy?
Makes liver make more Thyroid Binding Globulin
More thyroid binding globulin leads to more TSH being made which leads to more thyroxine (T3 and T4) being made
Why is pregnancy considered a euthyroid state?
Levels of free thyroid hormones remain the same since the levels of thyroid binding globulin increase
How does increased parathyroid activation increase calcium levels?
Inc PTH
Means kidney produces more enzymes to activate inactive Vit D
More active VIt D means more Ca2+ and phosphate absorption in GI tract
Kidney excretion of PO4- increases
How is glucose metabolism affected in mother in pregnancy?
Insulin resistance leads to increased plasma glucose and insulin levels so blood glucose levels for fetus are higher
What hormone leads to insulin resistance in the mother?
hPL (Human placental lactogen)
How can gestational diabetes Mellitus occur?
When mother already has risk factors for diabetes and the effects of normal insulin resistance in pregancy leads to gestational diabetes
How are glucose levels and insulin levels affected in pregancy?
Both elevated
What is gestational diabetes?
Diabetes that develops during pregnancy
Hyperglycaemia that falls above the normal range during pregancy
What are the risk factors for developing gestational diabetes?
BMI > 30kg/m^2
Previous macrosomic baby
FHx of DM
Ethnicity with high prevalence of diabetes
How do you diagnose/investigate Gestational Diabetes Mellitus?
Oral GLucose Tolerance test (give glucose drink then measure after 2 hrs)
Diagnose:
Fasting plasma glucose > 5.6mmol/L
Or
2hr plasma glucose of >7.8mmol/L
What are some complications that can occur to the mother with gestational diabetes?
Risk of:
-pre-eclampsia
-polyhydramnios
-premature labour
Why can GDM lead to polyhydramnios and premature labour?
Hyperglycaemia in baby inc urine output
The increased amniotic fluid volume cna lead to early labour
What are some labour ccompiations that can occur with Gestational DM?
Shoulder dystocia
Failure to progress
What are some complications that can occur to the fetus with Gestational DM?
Macrosomia
Congenital abnormalities:
-cardiac
-renal
-neural tube defects (cerebral palsy)
Hypoxia nd sudden intrauterine death
What are some complications that can occur to the neonate where there was gestational DM?
Hypoglycaemia (high insulin levels but not the elevated glucose anymore)
Resp distress
Jaundice
What changes to MSK and skin occur in pregancy?
Everything more loose and stretchy to cop with:
-additional weight
-COG changes
-preparing for childbirth
Why can bac pain, shoulder pain and tension headaches occur in pregnancy?
Changes in MSK
Progesterone relaxes muscles and ligament s
Inc Lordosis and kyphosis
Forward neck Flexion
Stretch abdominal muscles (impeded posture and strain paraspinal muscles)
Why can pelvic pain occur in pregancy?
Anterior tilt of pelvis
Increased mobility of sacroiliac joints and pubic symphysis
Why can carpal tunnel occur with pregnancy?
Fluid retetnion can compress structures such as the median nerev
What pigment is increased in production in pregnancy?
More melanin
What skin changes can be seen in pregnancy?
Chloasma/melasma of face
Line nigra
Palmar erythema
Spider naevi (vascular spiders)
What is linea nigra?
Line of pigmentation where the rectus muscles join
What is the definition of Pre—eclampsia?
Pregnancy induced hypertension of >140/90mmHg with proteinuria with or without maternal organs dysfunction AFTER WEEK 20
What is considered severe pre-eclampsia?
Severe hypertension that doesnt respond to treatment
What are the risk factors for pre-eclampsia?
40>yrs old
Nulliparity
Last pregnancy over10yrs ago
FHx
Previous Pre-eclampsia
BMI>30kg/m2
Pre-existing vascular disease
What is the pathophysiology of pre-eclampsia?
Insuffienct invasion of trophoblasts leading to shallow invasion of SPIRAL ARTERIES meaning they stay thin and have a high resistance
This leads to hypoperfusion and ischaemia to fetus
What are the symptoms of pre-eclampsia?
Head ache (cerebral oedema due to inc BP)
Vision disturbances
Epigastric pain
Oedema of hands and feet
Vomiting
SOB
What are some complications of pre-eclampsia to the mother?
Eclampsia
Cerebral haemorrhage
Renal failure
Pulmonary oedema
HELLP syndrome
What is eclampsia and why can it occcur due to preeclampsia?
Seizures
Due to the inc BP cerebral oedema and cerebral haemorrhages can occur
What is HELLP syndrome?
Haemolysis
Elevated Liver enzymes
Low Platelets
(DIC)
What Fetal complications can occur due to pre-eclampsia?
Asymetrical growth restriction
Oligohydromanios
Plancental infarct
Fetal distress
Premature delivery
Stilll birth
What examinations are done to asses pre-eclampsia?
Check for papiloedema (raised ICP)
Tendon reflex’s (Hyper-reflexia) indicates CNS function and seizure/eclampsia likelihood
How is eclampsia managed?
Give magnesium sulphate
