maternal changes in pregnancy Flashcards
what might pregnancy do?
- exacerbate a pre-existing condition
- uncover ‘hidden’ or mild condition
changes occur in pregnancy to cope with several events - name them:
- increase in size and metabolic requirements of uterus
- metabolic requirements of fetus
- removal of fetal waste products
- provision of amniotic fluid
- preparation for delivery and puerperium
which systems undergo changes in pregnancy?
energy balance respiratory system cardiovascular system gastrointestinal system urinary system endocrine system
what 2 hormones does the placenta make?
peptides and steroids
what are responsible for most of the changes?
-placental peptides hCG, hPL, GH -maternal steroids -placental and fetal steroids progesterone, oestradiol, oestriol -maternal and fetal pituitary hormones GH, thyroid hormones, prolactin, CRF
what is hPL?
human placental lactogen
Effects of placental steroids
renin/angiotensin system respiratory centre GI tract blood vessels uterine myometrial contractility -during pregnancy uterine muscle gets v big and thick, you don’t want it to contract and cause an early pregnancy, so you need to make sure it doesn’t contract
why is there a need to increase energy in pregnancy?
because of:
-increased output
to cope with increased respiration and cardiac output
-increased storage
for fetus
for labour and puerperium
glucose levels in first trimester
1st trimester is about building maternal reserves
- there is an increase in pancreatic beta cells and plasma insulin levels
- the islet of langerhans hypertrophy
- fasting serum glucose levels decrease - in stores and used by muscle
glucose levels in second trimester
2nd trimester is about fetal reserves
- fetus needs glucose
- human placental lactogen is released from placenta and causes insulin resistance
- increased availability of serum glucose, more crosses placenta
- but can cause diabetes
water gain in pregnancy
oestrogen and progesterone act on the RAAS system and activate it
- sodium retained, drags water in
- decrease thirst threshold
- decrease in plasma oncotic pressure
- plasma volume increases by 40-50%
- can cause oedema
how do oestrogen and progesterone affect the respiratory system?
oxygen consumption is increased -increase respiratory sensitivity to CO2 -ribs flare outwards -breathe more deeply, minute volume goes up -arterial PO2 increases, PCO2 decreases
what can happen to the uterus at the end of pregnancy?
uterus moves upwards, can actually push up on your diaphragm
changes to maternal blood in pregnancy?
- increased efficiency of iron absorption from gut
- risk of anaemia
- Haemodilution, concentration of Hb falls
- white cell count increases and clotting factors - blood becomes hypercoagulable
- increased fibrinogen for placental separation, but increased risk of thrombosis
fetal blood
different hb, maximise o2 uptake from the mothers blood in the placenta
effect of smoking?
maternal carboxy-Hb is more permanent and reduces increased binding
-fetal hypoxia
what are the effects of pregnancy on the cardiovascular system?
expanding uterus
- pushes heart round
- changes ECG and heart sounds
increased cardiac output
- increased heart rate and stroke volume
- decreased BP, so peripheral resistance DROPS
under normal circumstances what is blood flow like in pregnancy?
high volume and low pressure
what are the effects of pregnancy on vessels?
- steroids causes vasodilation, so decreased BP and decreased TPR
- increased flow to: uterus, placenta muscle, kidney and skin
- neoangiogenesis, including extra capillaries in skin, assist in heat loss
how do steroids affect the GI tract in pregnancy?
increase thirst
decreases GIT motility - constipation
LOS relaxed - acid reflux
what dietary supplementation is advised in pregnancy?
folic acid
what is folic acid used for?
DNA production, growth, production of red blood cells
folic acid deficiency is linked to what?
spina bifida- neural tube defect
what are the effects of pregnancy on kidneys?
- increased blood flow to kidney
- increased filtration rate
- increased clearance of creatinine, urea and uric acid
what are the effects of pregnancy on urinary system?
urinary tract dilates and relaxes, risk of increased UTI
what do pregnant women need to pee so much?
as the uterus expands in the pelvis it pushes against the bladder
- bladder doesn’t distinguish between pressure within from urine within or other pressure
- just signals that you need the loo
changes in uterine size
-huge increase in muscle mass
-huge increase in blood flow
placenta and uterus
changes in cervix?
cervix retains the pregnancy
- increase in vascularity
- tissue softens from 8 weeks
- proliferation of glands, so increase in mucosal production, anti-infective effect
why does tissue in the cervix soften?
to prepare for the gradual expansion
after pregnancy what happens?
- dramatic fall in steroids after placenta delivery
- uterine muscle looses oedema, contracts slowly
- never returns to pre-pregnancy size
- removal of steroids permits action of raised prolactin on breast
puerperium
is period of about six weeks after childbirth during which the mother’s reproductive organs return to their original non-pregnant condition
