Hormones of the Placenta Flashcards
What happens halfway through the ovarian cycle?
surge in LH causes ovulation, ovulated follicle turn into corpus luteum which produces progesterone for second half of cycle
How is corpus luteum kept in tact if pregnancy occurs?
TBs release hCG to keep corpus luteum producing progesterone and keep endometrium in decidualised state
how long is progesterone exclusively produced by CL?
5-7weeks
list some of the roles of hCG
endometrium decidualisation upkeep, inhibits smooth muscle contraction, stimulates blood vessel formation, promotes syncytialisation, modulates immune system
describe the luteal placental shift
shift from corpus luteum to placenta as dominant progesterone producer at around week 5-7
differentiate between prog and est levels across pregnancy
prog levels peak early and remain high
estrogen starts to increase closer to term until it reaches peak which influences when baby will be born
can the placenta make progesterone and estrogen?
placenta can make progesterone but needs DHEA to make estrogen which it borrows from the baby (baby makes DHEA out of prog in adrenal gland)
list the 3 different types of estrogen
estradiol: out of preg
estriol: only made in preg
esterone: mainly in preg
how much estrogen is produced across a pregnancy compared to usual production?
15,000pg/ml in preg compared to 200pg/ml
what gestation is fetal adrenal gland sufficiently mature enough to make DHEA?
7-8weeks
what is low estrogen in pregnancy associated with?
inhibition of feminisation of fetus
How does estrogen assist with labour?
makes uterus ready to respond to oxytocin and prostaglandins by initiating growth of receptors of surface, increases gap junctions which changes contraction manner to top to bottom
what hormone induces proliferation of endometrium, endo glands and spiral arteries?
progesterone
How does hCG/progesterone affect normal fever response in pregnancy/labour?
hCG/progesterone inflicts an anti-inflammatory response to prevent rejection of fetus which makes uterus in pregnancy an immune privileged site, reducing normal capability of inflammatory cells such as fever
What hormones are responsible for depositing fat early in pregnancy and later releasing these stores by causing insulin resistance?
HPL and PGH
describe role of prostaglandins in labour
stimulate contraction of uterus once estrogen initiates receptor growth, helps soften cervix, propagation of calcium in smooth muscle -> contractions, help placenta detach from uterus
how can prostaglandins be stimulated?
membrane sweep, local administration with gel
describe positive feedback look of placental corticotropin releasing hormone (CRH)
CRH has positive feedback causing increase in CRH, some CRH -> cortisol which increases prostaglandins, prostaglandins reduce progesterone, some CRH enters fetal blood -> DHEA which is turned into estrogen -> increased prostaglandin receptors on uterus = IOL
