Endocrinology of Pregnancy Flashcards
Fxn of placenta
- maintain corpus luteum during first 7-10 weeks
- Adjust maternal metabolism –> nutrients go to fetus
- Stim maternal circulatory system to transport gases and nutrients to and from the growing fetus
- Dampen uterine contractility
- Prepare maternal tissues for childbirth
- Prepare breasts for lactation
- Make hormones that lead to parturition
Insulin sensitivity in preggos
Early on:
Insulin sensitivity
Later on:
Insulin resistance
Anemia of pregnancy
increase in bv (30-40%) more than RBCs
What resp. concerns do we have for preggos?
Resp alkalosis
(due to increase in TV)
–>
Compensated metabolic acidosis –> lower buffering capacity –> earlier DKA
Increase in GFR in pregnancy leads to what?
- Decrease in BUN and Cr
- Increased renal bf
- Altered tubular fxn (glucosuria)
- decreased ureteral peristalsis (pyelo)
- Lowered osmostat for vasopressin release and thirst (hyponatremia)
GI changes in pregnancy
- Decreased fxn in lower esophageal sphincter (LES)
- GERD
- Aspiration pneumo - Decreased stomach emptying, peristalsis
- gastroparesis
- delayed absoprtion
- constipation - Decreased GB emptying
- cholestasis
Relaxin
potent stimulus in rats to increase GFR and renal plasma flow and decrease SVR
Softens cervix, lengthens interpubic ligament
Syncytiotrophoblasts
- major site of what?
major site of protein and steroid production
Hemochorioendothelial placentation
- direclty bathed by maternal blood w/in intervillous space
- separated from fetal blood by several layers of tissue
What day does the placenta take over and make hormones?
8-9 weeks
What hormones are actively metabolized by placenta?
- T4–> T3
by Type III Monodeiodinase - Cortisol –> cortisone
by 11-B hydroxysteroid dehydrogenase
When is hCG levels highest?
10-12 weeks
*also when women are the sickest
!!! hCG has TSH activity at high levels –> makes T3 and T4 –> downreg TSH
- dont give antithyroid thinking its graves
hPGH
Secreted by syncytiotrophoblast
Not regulated by GHRH
Secreted tonically, and replaces pit GH ~ 20 weeks
Does not cross placenta but regulates IGF-1
Major insulin resistance hormone of pregnancy
Potent somatogen
- lost during labor and 1 hr after placenta removal
hPL
- Facilitates mobilization and utilization of FFAs for energy by increased lipolysis
- Both insulin and anti-insulin fx
- Stimulate insulin secretion
- Weak GH activity and mainly a lactogen - promotes growth of mammary tissue and stim prolactin
Major insulin resistance hormone of pregnancy
hPGH
- decreased in growth restricted fetuses
- women with pre-existing insulin resistance –> GDM –> further insulin resistance form placental hormones and inadequate insulin secretion
What should we give women with luteal defect?
Give women progesterone prior to 8-11 weeks
- since corpus luteum cant make it
Progesterone synthesis requires LDL receptors on trophoblast plasma membranes. Progesterone is the substrate for synthesis of
cortisol and aldosterone
How can we prevent preterm labor?
give progesterone - inhibits uterine contraction
- smooth muscle relaxant (GI, uterus, GU)
Progesterone clinical correlates in preg
- given for luteal phase defects
- prevents preterm labor
- misoprostone acts as abortifacent
- autoimmune ds may improve
Estrogen fx on prl
Induces lactotrophs –> inhibits dopa –> increases PRL
But
Antagonizes PRL at level of breast
E FX on T3 and T4
E Increases them
Double trouble
- recall that hCG acts like TSH –> makes T3 and T4 –> neg feedback decreases TSH in early preg.
- dont give antithyroid thinking its graves
What hormones arrest the transit of the embryo in the reproductive tract?
Progesterone and hCG
What hormone creates a suitable environment to enable placental attachment
progesterone and hCG
Chorionic ACTH-CRH system
involved in parturition (giving birth)
Day 4: the embryo differentiates into
What happens on day 6-7?
inner cell mass (fetus)
and
Trophectoderm (placenta)
Endometrial attachment of trophoblast
