Physiology of Pregnancy and Lactation

Question 1

what happens 3-5 days after fertilisation

Answer 1

transport of blastocyst into the uterus

Question 2

what happens 5-8 days after fertilisation

Answer 2

blastocyst attaches to lining of uterus

Question 3

what does the blastocyst include

Answer 3

inner cells (embryoblast) - which become embryo

outer cells - trophoblast cells, become the placenta

Question 4

what does the placenta do

Answer 4

produces hormones to maintain pregnancy

trophoblast cells differentiate into syncytiotrophoblasts which invade decide and break down capillaries to form cavities filled with maternal blood

developing embryos sent capiliaries into the syncytiotrophoblast projections to form placental villi

has 2 ways of exchange - respect gases, nutrients, metabolites between mother and foetus

Question 5

when is the placenta and foetal heart functional by

Answer 5

5th week of pregnancy

Question 6

what hormone signals the corpus lute to continue to secrete progesterone in pregnancy

Answer 6

HCG (human chorionic gonadotrophin)

Question 7

what does prolonged progesterone secretion by corpus luteum cause in pregnancy

Answer 7

stimulates decidual cells to concentrate glycogen, protein and lipids

Question 8

how does the placenta act as the ‘lungs’ for the foetus

Answer 8

gas exchange between oxygen rich maternal blood compared to the foetal circulation

reversible exchange of carbon dioxide from foetus to mother

Question 9

what 3 factors facilitate the supply of the foetus with oxygen

Answer 9

1. foetal Hb (increased ability to cary O2)
2. higher Hb concentration
3. Bohr effect (fetal carries more oxygen in low pCO2 than in high pCO2)

Question 10

how does the foetus get water

Answer 10

increase in water exchange across an osmotic gradient up till the 35th week of pregnancy

Question 11

how do nutrients and electrolytes cross the placenta

Answer 11

can only cross from mother to foetus

glucose passes via simplified transport to the foetus

free diffusion of fatty acids across the placenta

Question 12

what are teratogens

Answer 12

drugs that cross the placenta and effect the foetus, eg.

tetracycline, carbamazepine, thalidomide

alcohol, nicotine, heroin, coccaine, caffeine

Question 13

what does HCG do

Answer 13

prevents break down of corpus luteum

effects the testes of male foetus- development of sex organs

Question 14

what does HPL (human placental lactogen)

Answer 14

produced from week 5

growth hormone like effects

decreases insulin sensitivity

involved in breast development

Question 15

what does progesterone do in pregnancy

Answer 15

development of decimal cells

decrease of uterus contractility

preparation for lactation

Question 16

what does oestrogen’s do in pregnancy

Answer 16

enlargement of uterus

breast development

relaxation of ligaments

Question 17

how should HCG increase in early pregnancy

Answer 17

serum levels should double every 48 hours in a singleton early pregnancy

Question 18

what changes can you monitor via HCG levels

Answer 18

ectopic pregnancy - static or slow rising

failing pregnancy - falling

ongoing viable pregnancy - doubling or >60% rise

Question 19

side effects of increased HCG

Answer 19

nausea
vomiting

high levels can occur in:
multiple pregnancy
molar pregnancy

Question 20

when does HCG start to go down again in normal pregnancy

Answer 20

12-14 weeks

woman starts feeling better - less morning sickness

Question 21

how much does the mothers cardiac output increase in pregnancy

Answer 21

30-50%

Question 22

when does cardiac output decrease in pregnancy

Answer 22

last 8 weeks

foetus compressing vena caca

Question 23

what normal changes can be seen in pregnancy because of raised CO

Answer 23

ECG changes
functional murmurs
heart sounds

Question 24

what happens to plasma volume in pregnancy

Answer 24

increases proportionally with cardiac output

Question 25

why is Hb decreased in pregnancy

Answer 25

increased plasma volume causes increased dilution

Question 26

what happens to iron requirements in pregnancy

Answer 26

increases significantly iron supplements often needed

Question 27

what respiratory changes happen in pregnancy

Answer 27

changes occur due to increase progesterone and large uterus decreasing lung function progesterone lowers CO2 levels O2 consumption increases to meet metabolic needs to foetus

Question 28

what happens to the urinary system in pregnancy

Answer 28

GFR and renal plasma flow increases increased re-absorption of ions and water due to placental steroids and aldosterone increase of urine formation

Question 29

how do postural changes in pregnancy cause changes in renal function

Answer 29

decreased in up right position increased in a supine position (lying flat) increased in a lateral position during sleep (lying on side)

Question 30

what is pre-eclampsia

Answer 30

pregnancy induced hypertension and proteinuria increasing BP since 20th week kidney function declines, salt and water retention leads to oedema formation

Question 31

who is pre-eclampsia more common in

Answer 31

``` pre-existing hypertension diabetes autoimmune disease renal disease family history of pre-eclampsia obesity multiple pregnancy ```

Question 32

what is the average weight gain in pregnancy

Answer 32

11kg

Question 33

what is the pregnancy weight gain from

Answer 33

``` foetus placenta amniotic fluid extracellular fluid other tissue - fat uterus and breast tissue increase in blood ```

Question 34

how many extra calories a day do you need in pregnancy

Answer 34

200

Question 35

what are the 2 phases of metabolism in pregnancy

Answer 35

1st-20th week - mothers anabolic phase - anabolic metabolism for mother - low metabolic needs of foetus 21st-40th week (catabolic phase) - high metabolic demands of foetus - accelerated starvation of the mother

Question 36

what happens in the mothers anabolic phase

Answer 36

Normal or increased sensitivity to insulin Lower plasmatic glucose level Lipogenesis, glycogen strokes increase -growth of breasts, uterus, weight gain

Question 37

what happens in the mothers catabolic phase

Answer 37

increase in maternal insulin resistance increased transport of nutrients through placenta lipolysis insulin resistance is caused by human placental lactose, cortisol and growth hormone

Question 38

what nutrients need to be taken in pregnancy

Answer 38

``` Folic acid - reduces risk of neural tube defects Vitamin D supplements High protein diet, higher energy uptake Iron supplements B-vitamin -erythropoesis ```

Question 39

what happens to the uterus towards the end of pregnancy

Answer 39

gets more excitable due to the oestrogen:progesterone ratio falling oestrogen increases contractility oxytocin increases contractions

Question 40

what drugs can be used to induce labour

Answer 40

vaginal prostaglandins | oxytocin

Question 41

what are Braxton hicks contractions

Answer 41

tightening of uterus increase towards the end of pregnancy

Question 42

what causes positive feedback to increase oxytocin release

Answer 42

stretch of the cervix by foetal head increased oxytocin increases uterine contractions also increases prostaglandin secretion which again increases contractions

Question 43

1st stage of labour

Answer 43

cervical dilation | 8-24 hours

Question 44

2nd stage of labour

Answer 44

passage through birth canal (few mins to 120 mins)

Question 45

what is the 3rd stage of labour

Answer 45

expulsion of placenta

Question 46

what hormones are involved in producing lactation

Answer 46

prolactin oxytocin oestrogen progesterone

Question 47

what does oestrogen do for lactation

Answer 47

growth of ductile system prevents milk production in pregnancy

Question 48

what does progesterone do for lactation

Answer 48

development of lobule-alveolar system prevents milk production in pregnancy

Question 49

what does prolactin do for lactation

Answer 49

stimulates milk production 1-7 days after birth, prolactin induces high milk production stimulates colostrum (first form of milk produced)