2/20 Physio of Pregnancy - Zachow

Question 1

maternal recognition of pregnancy

Answer 1

week 3-4

HPA axis role is replaced by…

• placenta:GnRH → targets trophoblast:hCG
  
  • hCG (LH analog) binds to LHreceptors in corpus luteum, stimulates production of progesterone/P4

recall: corpus luteum cell types

1. theca lutein
2. granulosa lutein

Question 2

maternal fetal steroidogenesis, metabolism

Answer 2

Question 3

synthesis map of…

• progestins
• androgens
• glucocorticoids
• estrogens

Answer 3

keys:

• NEED progestins to get androgens
• NEED androgens to get estrogen

Question 4

maternal-fetal steroidogenesis

Answer 4

Question 5

relative change in maternal serum hormone levels

E3 : E2

Answer 5

0-30wk: equimolar (1:1)

• antagonism of uterine/myometrial ER

30-40wk: increase in E3-to-E2 ratio (10:1)

• activation of uterine ER

Question 6

maternal-fetal thyroid fx

1st trimester

Answer 6

• hCG can stimulate TSHreceptor to some degree → T3, T4 production
• estrogen → increased production of TBG

in a healthy preg, see suppressed TSH and high T4

• mimics primary hyperthyroidism! (is this right?)

Question 7

RAS and pregnancy

Answer 7

estrogen upregulates RAS

• increases fluid volume (good thing)
• has the potential to vasoconstrict (bad thing, bc it would lead to massive HTN)
  
  • overcome via maternal production of RELAXIN, local vasodilators (keeps bp fairly nl)