Physiology of pregnancy and lactation Flashcards
Which cells form a) the embryo and b) the placenta?
a) inner cell mass b) trophoblast
How does the blastocyst become embedded within the endometrium? When is this process usually complete by?
Cords of trophoblastic cells invade the endometrium. 12 days
How is oxygenation of foetal blood made possible? (3)
Has a higher oxygen affinity than maternal haemoglobin; foetal blood has more haemoglobin; Bohr effect
How long does the placenta secrete HCG for?
10 weeks
What is the purpose of the placenta secreting HCG?
Maintains the corpus luteum
What does HCG do in XY foetuses?
Stimulates leydig cells to produce testosterone
Where does fertilization usually occur?
Ampulla
Implantation occurs around hen?
5-7 days after fertilization
What consequences can foetal release of corticotrophin releasing hormone have on the mother?
Hypertension
Insulin resistance/gestational diabetes
Describe cardiac output during pregnancy
Increases 30-50% beginning 6 weeks gestation, peaking around 24 weeks.
Decreases in last 8 weeks (vena cava compression)
Two nutritional “phases” of pregnancy
Anabolic (weeks 1-20)
Catabolic (weeks 21-40)
Special nutritional needs in pregnancy (6)
High protein/energy diet Iron supplementation B Vitamins Folic acid Vitamin D3, calcium Vitamin K before parturition
What underlies the increase in excitability of the uterus as gestation increases?
Increasing oestrogen:progesterone ratio
Cardiac output in pregnancy
Increases due to increased stroke volume and heart rate
Blood pressure during pregnancy
Falls due to lower peripheral resistance until 24 weeks; steady rise until term
Causes of oedema in pregancy (2)
Salt and water retention due to increased angiotensin II
Venous stasis due to pressure effect of uterus
Haematological changes in pregnancy (2)
Dilutional anaemia
Hypercoagulable state
Respiratory changes in pregnancy (3)
Increased tidal volume
Increased o2 consumption
Decreased residual volume
Urinary/renal changes in pregnancy (2)
Increased GFR
5% have asymptomatic bacteruria
Potential consequences of increased GFR
Mild glycosuria/proteinuria
Approximate weight gain in pregnancy
12.5kg
Hormone responsible for:
a) breast duct development
b) alveolar/lobule system development
a) oestrogen
b) progesterone
Hormone which stimulates milk production
Prolactin
Hormone which stimulates milk expression
Oxytocin
Stimuli for the milk let-down reflex (2)
Suckling
Sound of child’s cry
Where is oxytocin released from?
Posterior pituitary
