Physiological Changes in Pregnancy- important Flashcards
IMPORTANT
What releases beta HCG?
from trophoblast from blastocyst
What does beta HCG do?
Supports corpus luteum which allows progesterone to still be produced, sustain uterus,
Beta HCG and corpus luteum needed to sustain progesterone until placental production is sufficient (10-12 weeks)
What is the cause of morning sickness?
Beta HCG
Which hormone is measured in pregnancy tests?
Beta HCG
High persistence in Beta HCG can lead to what?
Ectopic pregnancy
What is an ectopic pregnancy?
Fertilised egg implants itself outside of the womb, usually in fallopian tubes
High persistence of Beta HCG can be a sign of what?
Pineal tumours, trophoblastic tumours
When does the placenta take over from the corpus luteum?
At 10-12 weeks
What are the effects of progesterone on the uterus?
Smooth muscle relaxation- prevent fetal expulsion
Cervical plug formation- microbial barrier
Also relaxes other smooth muscle in body: blood vessels, GIT, ureters, bronchi
Inhibit uterine contractility
What are the effects of progesterone on homeostasis?
Respiratory centre- hyperventilation
Renin-angiotensin- Na reabsorption
What are the effects of progesterone on the breast?
Lobular tissue development- but inhibits milk production
What are the effects of oestrogen on the uterus?
Myometrial cell growth- for growing fetus
Connexin insertion- electrochemical links (gap junctions) between myometrial cells- unified, strong uterine contractions
Oxytocin receptor insertion-prepared for labour- unified, strong uterine contractions
PGE2 (prostaglandins) production stimulated- softens cervix
What are the effects of oestrogen on the breast?
Breast duct development- but inhibits milk production
How is cortisol stimulated to be released from adrenal cortex?
Hypothalamus release corticoptropin releasing hormone
Cause anterior pituitary gland to release corticotropin which is adrenocorticotrophic hormone
Causes adrenal cortex to release cortisol
How is oestrogen produced in pregnant women?
By placenta and fetus interaction
Corticotropin releasing hormone released from placenta
Adrenocorticotrophic hormone released from APG from fetus and mother
Cause cortisol to be released from adrenal cortex from mother
Cayse cortisol and DHEA to be released from fetus
DHEA cause oestrogen to be released from placenta
DHEA travel across placenta cause oestrogen production from placenta, go to mother
A sudden surge in which hormone is thought to act as a trigger for onset of labour?
Corticotropin releasing hormone
What are the maternal effects of human placental lactogen?
Insulin resistance- decreases glucose utilization, increases blood glucose
Lipid breakdown- FFA production
Breast development
What are the fetal effects of human placental lactogen?
Promotes growth- more glucose available for this
How does clotting change during pregnancy?
Anti-thrombin falls
How does oestrogen effect HR?
Increases contractility
Increases SV
Increases cardiac output
Increases heart rate
What makes a mother flushed?
Progesterone generates vasodilation
What causes varicose veins when pregnant?
Venous compression by expanding uterus
What makes mum short of breath?
Diaphragm pushed up by uterus and pregnancy
Diaphragm not main muscle of respiratory action
Central chemoreceptors have increased sensitivity causing increased ventialtion, make mum feel breathless
How does carbondioxide control of ventilation change?
Central chemoreceptors drive up respiratory sensationon- progesterone affected this Make mum feel breathless Ventilation increases CO2 decreases Homeostasis reached
Why does mother need to go to toilet more frequently?
1) Renal blood flow increased as increased plasma volume so decreased renovascular resistance
2) Increased perfusion= increased GFR
3) Increased GFR, not all able to absorb, mum need to go to toilet more
1) Pressure on bladder by enlarging uterus
Breast changes during pregnancy?
Darkening of areola
Increased vascularity
Hyperplasia of fat deposits- draw on these to sustain baby shortly after birth
Increase glandular tissue- give enlarged breasts
What does prolactin do?
Increases milk production
Inhibits ovulation when breast feeding
What inhibits prolactin?
Oestrogen and progesterone
What are all the different hormones that affect the breast during pregnancy?
Oestrogen- mammary duct development
Progesterone-lobular tissue development
Prolactin- stimulates milk production (not able during pregnancy, inhibited)
Oxytocin- stimulates milk ejection from mum
How is prolactin stimulated to be released?
Prolactin releasing hormone released from hypothalamus
Prolactin released from anterior pituitary gland
Why does oestrogen and progesterone levels fall after pregnancy?
Placenta lost from mum
Where is oxytocin released from?
PPG
When is oxytocin also signalled to be produced?
Nipple stimulation
Cervix/vaginal distension during labour
