maternal changes in pregnancy Flashcards
what are the main causative factors for physiological changes in maternal women
- high steroid levels (high oestrogen and progesterone)
- mechanical displacement (huge mass in abdomen)
- requirements of foetus
maternal changes designed to cope with pregnancy
- An increased size of the uterus
- Increased metabolic requirements of the uterus
- Structural and metabolic requirements of the foetus
- Removal of foetal waste products
- The production of amniotic fluid
- Preparation for delivery and puerperium
effect of placental peptides on mother
hCG released first
hPL (human placental lactogen) also released
hPL is v similar to growth hormone. it causes woman to become hypertensive and increases glucose in blood (is antiinsulin.
effect of maternal steroids on mother
after 7 weeks, CL dies as no longer required, placenta takes over oestrogen + progesterone production (high concs)
what are placental and fetal steroids
mainly progesterone and oestrogen
what are maternal and fetal pituitary hormones
GH released
increase thyroid hormone production (inc, metabolic rate)
prolactin produced (allows lactation after delivery)
CRF (corticotropin releasing factor) released
effects of high placental steroids
high steroids can act on different receptors other than their own - so can affect multiple systems:
- Affect the RAAS system (thus blood pressure)
- Affect respiratory centre
- GI tract
- Blood vessels (cause massive vasodilation)
- Uterine myometrial contractility
why do we need to increase energy levels in pregnancy
- increased output of energy, through increased respiration and cardiac output
- store energy for foetus to use
- for labour and puerperium
how much weight gain occurs in pregnancy
12.5-13kg put on
4-5kg in fat and protein stores in anterior abdominal wall.
how does basal metabolic rate change in pregnancy
350kcal/day during mid-gestation.
It increases by about 250kcal/day by late gestation.
how is mother adapted to provide child with high glucose
mother becomes insulin resistent due to hPL
so can have constant stream of glucose across the placenta by faciltated diffusion
how is mother adapted to provide child with high glucose in first trimester
pacreatic beta cells increase in number due to slight insulin resistance .’.
plasma insulin increases .’. more glucose used up as stores/used by muscle
so maternal glucose stores are built.
(fasting serum glucose decreases)
how is mother adapted to provide child with high glucose in second trimester
hPL and steroid levels high = high insulin resistance
insulin cannot overcome this resistance .’. less glucose enters sores .’. serum glucose increases .’. glucose conc gradient increases at the placenta
IS NORMAL - NOT DIABETES
why may a pregnant lady develop diabetes in 2nd trimester
in 2nd trimester in general, woman becomes insulin resistant .’. hyperglycaemic. IS NORMAL.
but if woman has family history of diabetes, , is overweight or has bad genes this may push her over the edge and she becomes diabetic (gestational diabetes).
how does water content change in a pregnant woman
inc in total body water - inc to 8.5L
why is there an inc in total body water in pregnant women
due to high E2 and progesterones acting as mineralocorticoids on the RAAS system.
increase retention of Na+ in the kidney .’. water moves along with it = increased water retention = increased plasma volume
reset thirst threshold in the brain
what happens to the extra water content in the pregnant mother
is distributed in plasma
some water goes to fetus, placenta and amniotic fluid
also causes oedema in the ankles (extra fluid &reduced venous return - due to mass in chest impeding venous return)
oedema in lungs (dangerous)
why may pregnant women get odema in their ankles
extra fluid &reduced venous return - due to mass in chest impeding venous return
how does oestrogen and progesterone affect respiratory of pregnant woman
increased sensitivity of resp centre to CO2 .’. breathe more deeply .’. minute volume increases by 40%
what would blood gas of a pregnant woman show
bc minute vol increases by 40%, we see:
Arterial PO2 is high.
PCO2 is low.
what is the benefit of increased minute vol in pregnant women
helps facilitate placental gas transfer.
high PO2 in maternal blood.’. steep gradient for o2 to diffuse into fetal blood
low CP2 in maternal lood = gradient for high fetal CO2 to difuse into maternal blood
how doe maternal blood change in pregnancy
- plasma vol increased
- red cell mass inc (more erythropoiesis)
- hb decreased (bc although red cell mass = increased, plasma vol has increased by a huge amount)
so blood has haemodilution - looks like anaemia but isnt.
how is mother adapted for increased erythropoeisis in pregnancy
maternal gut is also more efficient at absorbing iron
inc in leukocytes
inc in clotting factors
why is there inc risk of clotting in pregnat women
blood is hypercoagulable.
increased fibrinogen for placental separation
increased risk of thrombosis
