Session 8- Maternal Physiology and Pregnancy Flashcards
what 4 hormones drive the adaptations in pregnancy
hCG
oestrogen
Progesterone
relaxin
how does the mum immune system adapt
To prevent rejection of the fetus, there is a reduction in cell-mediated immunity and TH1 cytokine production.
This is balanced by an increase in TH2 cytokines and humoral immunity. This means that pregnancy can improve TH1 mediated conditions, like psoriasis, and worsen TH2 mediated conditions like eczema.
hCG also suppresses IgA, IgG and IgM production, leading to maternal immunosuppression.
what are the consequences of the shift in immune system of the mother
-mother is in an immunosuppressed state so is more susceptible to infection (flu)
why does respiration need to change in pregnancy
baby needs
- o2 delivery
- co2 removal
mum needs
- o2 delivery to organs and periphery
- increased o2 supply and co2 clearance
how does resp change in pregnancy
overall increase in tidal volume by 30-40% which increases minute ventilation by 50%
pH change
how is the change in resp achieved
the ERV is increased which increase TV
how does TLC change and why
decrease by 5%
elevation of diaphragm
what causes dyspnoea in pregnancy
hyperventilation and decreased PaCo2
what is hyperventilation
minute vent goes up no RR
adaptations in CVS- volume
in early pregancy increased stroke volume and cardiac output
in late pregnancy increased HR
increased progesterone
how does progestrone affect the CVS in pregnancy and what is the effect of this
smooth muscle relaxation
- decreased Systemic vascular resistance
- drop in BP (Tri 1& 2)
what is the normal BP in pregnancy
140/90
how is clotting affected in pregnancy
increased procoaglulants
decreased antocoagulants
reduced fibrinolysis
hypercoagulable state- increased no of thromboembolic events
consequences of changes in CVS
hypercoagulable state- increased thromboembolic state
change in plasma volume» change in RBC volume (dilutional anaemia)
increased RAAS- increased BP
how does renal/urinary system adapt- physiology
systemic vasdilation = increased RBF
- increased GFR by 50%
- decrease serum urea and creatinine ny 25%
decreased PCT absorption
-Glucosuria ( cant keep up with high GFR)
how does the renal system adapt structurally
structural
- smooth muscle relaxation and obstruction
- increased lidney size and ureters
- decreased speed of urine passage
how does the GI system adapt
progesterone causes smooth muscles relaxation throughout the GI tract which causes slow gastric emptying and can cause common symtoms of nausea, constipation and heartburn.
gallbladder emptying is reduced
adaptations of the thyroid
- oestrogen stimulates TBG hepatic production
- hCG has a similar alpha subunit to TSH so has a weal stimulating effect on thyroid
how does calcium metabolism change
the placenta contributes to the synthesis of calcitrol which aims to increase calcium absorption - more availibility for the foetus
what are the changes to glucose metabolism
glucose and amino acid metabolism are altered in pregnancy to favour nutritional supply to the fetus
- reduction in maternal blood glucose and amino acid concentrations
- diminished maternal responsivenes to insulin in second half of pregancy
- increase in maternal free fatty acid, ketone and triglyceride levels
- increased insulin release
what generates a maternal resistance to insulin
HPL human placental lactogen
what role does oestrogen play in adapting glucose metabolism in pregnancy
stimulates an increase in prolactin
what role does progestrone play in adapting glucose metabolism in pregnancy
increases appetite in the first half of preganacy and diverts glucose into fat synthesos
what is gestational diabetes
glucose intolerance that is first recognised in pregnancy and doesnt persist after delivery
where the resistance to insulin isnt met with a compensatory rise in maternal insulin leading to maternal hyperglycaemia
