Pregnancy - Montemayor Flashcards
How is pregnancy duration determined?
Date of last mestrual period (LMP)
What is the mean duration of pregnancy?
40 weeks total (gestational age)
Or
38 weeks from ovulation - (embryonic/fetal age)
When do HCG levels begin to rise after ovulation of a fertilized egg?
8 Days
What secretes HCG?
The trophoblast
What are the four major hormones of pregnancy?
- HCG
- Progesterone
- Estrogens
- Human Placental LActogen (hPl)/Human chorionic omatomammotropin (hCs)
What are the three types of estrogens to be aware of?
Estrodiol
Estrone
Estriol
Identify which line corresponds with what hormone.


In the first trimester, hCG rescues the corpus luteum to stimulate luteal estrogen and progesterone production. What takes over hormone synthesis from the corpus luteum?
The placenta
What subunit of hCG is detected by pregnancy tests?
Beta subunit. (beta-hCG)
What is responsible for morning sickness?
hCG
When does hCG peak?
~10 weeks of gestation.
What hormones is the structure of hCG similar to? Which is it most similar to?
LH, FSH, TSH
Most similar to LH
hCG binds to what receptor with high affinity?
LH receptors
What is the primary action of hCG?
Stimulates LH receptors on corpus luteum…
- Prevents luteolysis
- Maintains high luteal-derived progesterone production before the placenta takes over (1st 10 wks.)
What are the other actions of hCG?
–Weakly binds TSH receptors
•Transient gestational hyperthyroidism
–Stimulates fetal Leydig cells –> Testosterone
–Stimulates fetal adrenal cortex
When does the luteal-placental shift take place?
~8-10 weeks
What is the function of progesterone with regard to pregnancy?
•Absolutely required to maintain a pregnant uterus
–Quiescent myometrium
How is progesterone production an indicator of fetal health?
It isn’t, progesterone production is independent of fetus
High levels of progesterone production continues with the availability of?
•CYP11A1, and 3β-hydroxysteroid dehydrogenase (3β-HSD), and **maternal cholesterol **
What are the major actions of progesterone in pregnancy?
–↓ uterine motility/contractions
–↑secretory activity necessary for nouishment, growth, and implantation of the embryo
–↑ fat deposition early in pregnancy
•Stimulates appetite, diverts energy stores from sugar to fat
The placenta takes of luteal-production of estrogens, what does it need from the fetal adrenal gland?
Needs 19-carbon androgen (DHEA-S)
What is the feto-placental unit responsible for the production of?
–Estradiol-17β
–Estrone
–Estriol (major estrogen of pregnancy)
Can you use estrogen as an indicator of fetal health?
Yes, since its production depends on a healthy fetus
We discussed seven effects of estrogen in pregnancy, list as many as you can.
- –↑ Uteroplacental blood flow
- –↑ Uterine smooth muscle hypertrophy (mitogenic effect)
- –↑ LDL receptor expression on syncytiotrophoblasts
- –↑ Prostaglandins
- –↑ Oxytocin receptors
- –↑ Mammary gland growth
- –↑ Prolactin secretion (maternal pituitary)







