Endocrinology of Pregnancy Flashcards
What does Kisspeptin do?
Profoundly stimulates GnRH and initiate puberty
When is Kisspeptin usually seen to spike during menstrual period?
Right before ovulation causing LH surge
What is seen in a Basal Body Temperature chart?
Resting core temperature is measured every morning, mid-cycle there is first a decrease in BBT due to LH surge followed by an elevation in BBT showing ovulation, a dip past ovulation shows implantation and then a large increase to BBT due to progesterone
What is Resting Core Temperature?
Temperature taken as you wake up in the morning before energy is being consumed
Why does progesterone cause a 1 degree F increase after pregnancy?
Because progesterone is thermogenic
What time range must the ovum be fertilized around ovulation?
Within 24-48 hours
48 hours around ovulation
Where does fertilization normally occur?
In the ampulla
What is the first source of hCG?
Corpus luteum
What does hCG have similar functions as?
FSH
LH
TSH
hCG titer for “not pregnant”?
Below 5 mIU/mL
hCG titer for “pregnant”?
Greater than 25 mIU/mL
How long does 1,200 mIU/mL of hCG in early pregnancy take to double?
48-72 hours
How long does between 1,200-6,000 mIU/mL of hCG take to double?
72-96 hours
How long does it take for levels of hCG above 6,000 mIU/mL take to double?
Over four days
What cells create hCG?
Syncytiotrophoblasts
What releases relaxin?
Corpus luteum and later the placenta
What does relaxin do?
Promotes decidual angiogenesis of the endometrium
What are the two layers the placental epithelial cells form in the uterus?
Cytotrophoblasts
Synctiotrophoblasts
What anchors the placenta to the endometrium?
Columns of invading cytotrophoblasts
What forms Synctiotrophoblasts?
Fusion of cytotrophoblasts
What do Synctiotrophoblasts do?
Are in direct contact with maternal circulation and is the major source of steroid hormone production
What is a marker for corpus luteum and why?
17-hydroxyprogesterone because the placenta lacks 17alpha-hydroxylase
What effects does hCG have?
Stimulates secretion of P4 from corpus luteum
Stimulates Leydig cells of male fetus to produce testosterone
Immunosuppressive activity (stops mom from rejecting baby as a graft)
How much does progesterone increase in pregnancy?
100x increase in concentration
Roles of progesterone:
Inhibits T cell mediated allograft rejection
Maintains uterine quiescence
Proliferation of breast lobular-alveolar structures
Suppression of milk protein synthesis during pregnancy
What are the four estrogen types?
Estrone (E1)
Estradiol (E2)
Estriol (E3)
Estetrol (E4)
Where are the estrogens primarily made?
Ovaries (largest)
Placenta (moderate amount)
Liver, adrenals and breasts (not as much)
Where are most of the placental estrogens derived from?
Fetal androgens mostly DHEAS
What is estrogens effect on clotting?
Stimulates fibrinogen
What does estrogen cause in the myometrium?
Hypertrophy
Hyperplasia
Increased vascularity and blood flow to uterus
Role of estrogen, progesterone, oxytocin and prolactin in lactation?
Estrogen: promotes development of ductal breast tissue
Progesterone: proliferative factor for formation of breast lobular-alveolar structures
Oxytocin: acts on muscle elements to cause contraction of ductal system
Prolactin: induces secretion of milk
What does the placenta produce to negate uterine contractions?
Oxytocinase: an enzyme that negates effects of OT on contractions
What markers are used to screen for Down syndrome?
Alpha-fetoprotein (AFP)
hCG
Inhibin-A
Unconjugated Estriol concentrations
What will the levels of each of the markers in Down syndrome be?
AFP: low
hCG: high
Inhibin-A: high
Estriol: low
What is the role of CRH in early and late pregnancy?
Early: low levels; increases DHEA; inhibit contractions by increasing cAMP in myometrium
Late: high levels; activate prostaglandins in uteroplacental tissues to cause contractions
What allows prolactin to act on the posterior pituitary to secrete oxytocin in a pulsatile fashion?
Progesterone withdrawal
What produced relaxin and what does it do?
Corpus luteum and placenta
Decidual angiogenesis
Soften and widens pubic symphysis and SI joints
Inhibit uterine contractions
Progesterone affect on GI tract?
Increased secretions
Relaxation of SM
Decreased gastric emptying
Lowers esophageal muscle tone
What occurs to osmolarity in a pregnant women?
Decreased plasma osmolarity due to marked water retention
Why does edema occur in pregnancy?
Increased blood volume causes increased BP and decreased oncotic pressure due to decreased osmolarity
What effect does progesterone have on chemoreceptors?
Sensitizes them to CO2 causing as increase in ventilation and decreases arterial pCO2
What does a fall in maternal pCO2 cause?
More efficient transfer of CO2 from the fetus to the mothers blood
What accounts for the darkening or dermatologic adaptations of pregnancy?
Increased MSH (melanocyte stimulating hormone)
What occurs to bone metabolism in pregnant patients?
Increased parathyroid activity
Estrogens inhibit bone resorption as do progestins
Calcitonin levels slightly increase to counter PTH effect
Effect of pregnancy on biliary system?
Estrogen inhibits bile transport
Gallbladder contraction decreased by progesterone inhibiting CCK
What occurs to HR, CO, BP in pregnancy?
HR increase
CO increase
BP decrease
In first half of pregnancy what causes increased CO?
Increased SV
In latter half of pregnancy what causes increased CO?
Increased HR
