SGW - 8 (pregnancy)

Question 1

tissue constitute placenta barrier in 1st trimester?

Answer 1

syncytiotrophoblast
cytotrophoblast
connective tissue (around foetal capillaries)
fetal capillary (circles)

Question 2

placenta barrier in 3rd trimester?

Answer 2

syncytiotrophoblast

foetal capillary endothelium

Question 3

when does hCG peak?

Answer 3

at 8 weeks of pregnancy
rises from 4th week
then trails off from 8th week

Question 4

effects of maternal smoking on placenta?

Answer 4

reduced placental blood flow

therefore poorer foetal nutrition will REDUCE BIRTH WEIGHT (by about 200g)

Question 5

how does alcohol cross the placenta? causing?

Answer 5

by diffusion - lipid soluble (also small molecule)
can cause FAS - low foetal weight and growth retarded
(possibly mental retardation, head + facial abnormalities)

Question 6

why might cytomegalovirus be a health hazard in pregnancy? (normally common cold)

Answer 6

can cause teratogenesis

process by which congenital malformations are produced in an embryo or fetus

Question 7

what is given to prevent haemolytic disease of the new born?

Answer 7

anti-D therapy (antibodies) - prophylaxis given to mother
to neutralise the antigens in the mother’s blood
otherwise causes rapid haemolysis when bind to foetal RBC

Question 8

what is shed in the 3rd stage of labour?

Answer 8

the placenta
maternal tissue: decidua
(foetal: amniochorion membrane)

Question 9

where does IgG in foetal blood derive from?

Answer 9

mothers blood

Question 10

why can’t a neonatal immune disease by mediated by IgM?

Answer 10

only IgG can cross the placenta (via pino-endocytosis)

Question 11

why are the maternal adaptations to pregnancy required?

Answer 11

1. provide suitable environment for nutrition, growth and development of foetus
2. prepare mother for birth
3. prepare mother for support of new born

Question 12

where is hCG released and when does it peak?

Answer 12

from syncytiotrophoblast of blastocyst

peaking at 10 weeks gestation (pregnancy)

Question 13

function of hCG?

Answer 13

mimics LH on corpus luteum - preventing degeneration to maintain endometrium lining to support pregnancy via release of progesterone (and oestrogen)

Question 14

hormones involved in maintaining pregnancy?

Answer 14

oestrogen and progesterone (steroids)

Question 15

where is hCG released from? function?

Answer 15

cells of developing FERTILISED OVUM

stimulates CL’s released of BOTH progesterone and oestrogen to maintain endometrium, therefore pregnancy

Question 16

what does hCG mimic?

Answer 16

luteal phase (LH) of menstrual cycle (post ovulation)
menstrual cycle = ovarian (oestrogen + progesterone) + uterine cycles (endometrium lining, stratum functionalis + basalis)

Question 17

what does hCG reduce? why?

Answer 17

maternal IgA, IgG, 1gM
humeral immunity is depressed - stop rejection of placenta
BUT mother - more susceptible to viral infections

Question 18

function of progesterone? effects on mother?

Answer 18

relaxes SM

can lead to GI: reduced motility –> heartburn + constipation

Question 19

which oestrogen hormone in maternal serum/urine would best indicate foetal progress? why?

Answer 19

oestriol (E3)
this hormone is dependent on foetal ADRENAL and LIVER metabolism as well as placental function
low oestriol = foetal distress, early delivery may be desirable

Question 20

which hormones from the anterior pituitary stimulate breast growth?

Answer 20

oestrogen, progesterone, prolactin

Question 21

how does inhibin (from CL + placenta) prevents further pregnancies?

Answer 21

suppress FSH secretion - blocking follicular growth

Question 22

what are the changes in glucose which occur during pregnancy to the mother?

Answer 22

1. reduction in maternal glucose + AA CONC.
2. diminished maternal RESPONSE to insulin (insulin resistance) in 2nd 1/2 pregnancy (save glucose for foetus)
3. increase maternal free FATTY ACID, ketone, triglyceride levels (ALTERNATIVE metabolic fuel)
4. increased insulin RELEASE to a normal meal

Question 23

how are the changes to the maternal concentration of glucose achieved in pregnancy?

Answer 23

through combined actions of:
hPL (hCS)
oestrogen, progesterone, prolactin (all anterior pit.)

Question 24

function of progesterone on maternal appetite during pregnancy?

Answer 24

stimulates appetite in 1st half of pregnancy

diverts glucose into FAT SYNTHESIS

Question 25

function of oestrogen in pregnancy on maternal appetite?

Answer 25

stimulates an increase in prolactin release (anterior pituitary) - +ve feedback

Question 26

which hormones generate maternal resistance to insulin?

Answer 26

``` prolactin (stimulated by oestrogen) hPL (increase maternal appetite) glucose cortisol (stress hormone, release more fatty A - alternative fuel) (possibly oestrogen and progesterone) ```

Question 27

what are the effects on maternal glucose usage from all the hormonal changes?

Answer 27

maternal glucose usage declines gluconeogenesis increases maximising availability of glucose to foetus

Question 28

in later pregnancy, how are maternal energy needs met?

Answer 28

by metabolising PERIPHERAL fatty acids

Question 29

function of progesterone in early pregnancy?

Answer 29

stimulates appetite increase maternal deposition of fat (divert glucose to fat synthesis) (about 3kg of fat accumulated by mother)

Question 30

how is the 25% of maternal weight gain (about 3kg) from progesterone in early pregnancy beneficial to the mother in later pregnancy and after birth of baby?

Answer 30

maternal preparation e.g. breast growth (for lactation - why prolactin involved) and also may provide a reserve (fatty acids) for later pregnancy when foetal demands are greater (for glucose)

Question 31

what is the transport of glucose across the placenta limited by?

Answer 31

FLOW - simple diffusion | therefore maternal supply

Question 32

describe the effects of hPL (hCS) on mother during pregnancy

Answer 32

reduced uptake of glucose into maternal cells (from increase PERIPHERAL insulin resistance) - favour foetal supply hPL LOW in early pregnancy, but increases as placenta grows (released from placenta) has diabetogenic effect

Question 33

describe what happens after a maternal meal due to the effects of hPL (hCS) released from placenta? what can it lead to?

Answer 33

maternal meal --> transient maternal HYPER glycaemia --> INCREASE maternal insulin release from pancreas --> (hPL + other hormones) --> DECREASE uptake into maternal cells --> INCREASE availability of glucose to foetus (can lead to maternal HYPO glycaemia BETWEEN meals)

Question 34

aside from insulin resistance, what else does hPL (hCS) promote?

Answer 34

lipolysis

Question 35

how does hPL promote lipolysis?

Answer 35

lipids and ketones released are avaliable for energy in early pregnancy, PROGESTERONE increases maternal APPETITE and promotes STORAGE of glucose in fat stores (lipolysis of mother = more glucose for foetus)