L14 - Physiology of pregnancy COPY Flashcards
OVERVIEW
i) how many weeks is the average human pregnancy?
ii) which weeks correspond to each trimester?
i) 40 weeks
ii) 1st = 2nd = 12-26 weeks
3rd = 27 weeks - birth
ENDOCRINE CHANGES
i) what are the three main hormones in pregnancy?
ii) when are peak levels of bHCG seen? what is it initially released from? what is it later released from
iii) name three roles progesterone plays in pregnancy
iv) what hormone is known as the growth hormone of pregnancy? name two things it does
v) label the graph - why does B fall at 40 wks?
i) bHCG, oestrogen and progesterone
ii) peak HCG in week 8-10
- initially released from corpus luteum then from placenta
iii) progesterone - helps with implantation and maint endometrial lining, decreases uterine contractions, acts on smooth muscle to relax
- overall maint a state of quiescence
iv) oestrogen - breast growth and areolar enlargement
v) A - oestrogen, B - progesterone, C - HCG
- proges falls at 40 weeks to allow for uterine contractions at birth
THE PLACENTA AS AN ENDOCRINE ORGAN
i) which hormone is produced by the trophoblast? when is this first detectable?
ii) which placental protein does human placental lactogen (hPL) have a similar structure to? how does it affect metabolism and glucose?
iii) which placental hormone induces materal insulin resistance? what does this allow regulation of? what condition is this pathological in?
iv) name three things progesterone controls
v) name two things oestrogen controls
i) trophoblast produces HCG
- first detect at 8-9 days
ii) hPL has a similar structure to prolactin
- alters maternal carbohydrate and lipid metabolism
- provides steady state of glucose for fetal requirements
iii) hPG (human placental gonadotrophin) induces insulin resis
- allows regulation of fetal growth
- pathol in gestational diabetes
iv) proges controls quiescence, decreased electrical activity and decreased immune response
v) oestrogen controls growth of placenta and lactation
CLINICAL PICTURE OF HORMONES - HCG
i) how does HCG affect the corpus luteum? how is it affected by incresed progesterone production by the placenta?
ii) what does bHCG form the basis of?
iii) which three hormones can the alpha unit mimic?
iv) name two situations where large quantities are released
v) what can high levels cause?
i) maintains corpus luteum secretion of oes and proges
- decreases as placental production of proges increases
ii) pregnancy testing
iii) LH, FSH, TSH
iv) in multiple pregnancy and molar pregnancy
v) hyperemesis
CLINICAL PICTURE OF HORMONES - OES AND PROGES
i) where does progesterone relax smooth muscle? give three consequences of this
ii) how does proges maintain uterine quiescence?
iii) how does proges affect the immune system? how does it affect breasts? what does it provide a substrate for the fetus to make?
iv) how does oestrogen affect the uterus, cervix and breasts?
v) what hormone does oestrogen stimulate the synthesis of? what does this prepare the body for?
i) everywhere
- constipation, gastric reflux and subra pubic dysfunction
ii) maintainence of uterine quiescence by decreasing uterine electrical activity
iii) proges is an immune suppressor
- causes lobulo-alveolar development in breasts
- substrate for fetal adrenal corticoid synthesis
iv) growth of uterus, cervical changes and development of ductal system of breasts
v) oes stimulates synthesis of prolactin
- prepares body for breastfeeding
HAEMATOLOGICAL SYSTEM
i) what % increase is there in plasma volume of mother during pregnancy? what % increase is there in RBCs? what does this result in?
ii) what happens to cardiac output in pregnancy?
iii) what results from plasma colloid osmotic pressure falling and fluid moving to extracellular spce?
iv) how are clotting factors affecting by pregnancy? why does this happen? what must be watched out for?
v) how do levels of fibrinogen, platelets, factor VIII and VWF change?
i) 40% increase in plasma vol and 25% increase of RBCs
- bigger increase in plasma vol compared to RBCs results in dilutional anaemia
ii) increase in cardiac output
iii) peripheral oedema
iv) increased clotting factors > hypercoaguable state
- decreases risk of haemmorhage in birth but watch out for VTE
v) increase in plasma fibrinogen, plats, factor vIII and VWF
CARDIOVASCULAR SYSTEM
i) name three things that increased blood volume has implications on and how each of these are changed by pregnancy
ii) which two things increase to account for the increase in cardiac output?
iii) what % does the heart enlarge by in pregnancy? which type of murmurs are common? are these a cause for concern?
iv) which type of murmur should be investigated? what may it be a sign of?
i) cardiac output (increased), peripheral resistance (decreased) and blood pressure (decreased)
ii) increased stroke volume and heart rate
iii) 12% enlargement
- systolic murmurs are common and not concerning in 90% cases
iv) investigate diastolic murmurs - may be a sign of cardiomyopathy
PERIPHERAL VASCULAR RESISTANCE
i) is there constriction or dilation in the periphery? what hormone causes this?
ii) by how much is peripheral resistance decreased by?
iii) why is there only a slightly lower BP?
iv) how many litres does the blood volume increase from and to?
v) what does an increase CO and decreased PR allow for?
i) vasodilation due to progesterone
ii) decrease in peripheral resistance by 35%
iii) decrease in periph resistance but increase in CO
iv) 5L to 7.5L
v) increased blood flow to the baby
RESPIRATORY SYSTEM
i) what happens to the diaphragm in pregnancy?
ii) how does tidal volume change? why does this happen?
iii) does vital capacity change? does minute ventillation change?
iv) what happens to the ribcage? how does this change breathing frequency?
v) how does pCO2 and pO2 change?
i) it becomes raised
ii) increase tidal volume as there is increased CO so need to oxygenate the increased blood flow
iii) vital capacity stays the same but minute ventillation increases
iv) ribcage widens at the bottom therefore need to take deeper breaths to get all air in
v) increased pO2 and decreased pCO2
CLINICAL PICTURE OF RESPIRATORY SYSTEM
i) how does splinting of the diaphragm affect ventilation? what sensation does this cause?
ii) how does HR change? what does this result in?
iii) what does pregnancy have a lot of cross over symptoms with and is a high cause of maternal death therefore must be investigated for?
iv) what may cause fainting/dizziness? which trimester may this especially happen in?
i) increases ventilation and gives sensation of increasing shortness of breath
ii) raised heart rate can cause palpitations
iii) pregnancy has lots of crossover symptoms with PE
iv) low BP can cause fainting and dizziness
- especially happens in 2nd trimester
MSK/DERMATOLOGICAL
i) how is the spine affected?
ii) what happens to ligaments around the body? name two things this can result in? does this affect ability to labour?
iii) what can changes in collagen result in? what hormone controls this?
iv) name three ways skin pigmentation can change?
v) what can arise in the wrist as a consequence of oedema? give two symptoms of this? what causes it? when does it get worse?
vi) what happens if the sciatic nerve root gets compressed? what can help this?
vii) what can be a sign of anaemia?
i) get lumbar lordosis - increased spine curvature
ii) ligaments get more lax due to progesterone
- can result in pelvic girdle pain and pubic dysfunction
- pubic dysfunc doesnt affect ability to labour
iii) collagen changes can result in stretch marks (mediated by proges)
iv) linea nigra, melasma (face), darkened nipples
v) carpal tunnel
- numbness and tingling - gets worse at night
- caused by compression of ulna nerve
vi) compression of nerve root > sciatica
- refer to physio
vii) cramps can be a sign of anaemia
BREAST CHANGES
i) what hormone are breast changes mostly down to?
ii) what effect does this have on adipose tissue?
iii) what happens to the areloar area?
iv) which hormone causes enlarged breast lobules
i) oestrogen
ii) increases adipose tissue
iii) larger and darker areolar area
iv) proges enlarges breast lobules
UROLOGICAL CHANGES
i) by how many cm do kidneys increase during pregnancy?
ii) how much does renal flow increase by?
iii) what happens to GFR and tubular reabsorption? what does this result in?
iv) what happens to plasma levels of creatinine and urea? why?
v) what effect does progesterone have on ureters?
vi) what must be ruled out of a woman presents with flank pain?
i) 1cm
ii) 50% increase in renal flow
iii) GFR increases but tubular reabsorption stays the same
- can result in decreased glucose reabs > glycosyuria
iv) creatinine and urea decrease due to increased kidney function
v) progesterone causes dilated ureters
vi) flank pain > rule out pyelonephritis
THYROID
i) how do serum T3 and T4 levels change?
ii) how do levels of thyroid binding globulin change?
iii) how do free T3 and T4 levels change? why?
i) serum T3 and T4 increase
ii) increase in thyroid binding globulin
iii) free T3 and T4 remain the same or slightly fall due to an increase in thyroid binding globulin
