Part 6: Labor Flashcards
What enzyme is present in the placenta that ensures fetus cortisol levels are not in excess?
- Type 2 11-beta HSD.
- Converts cortisol to cortisone.
Defects in placental type 2 11-beta HSD are associated with what birth defects?
low birth weight.
What placental hormone targets the maternal adrenal cortex to secrete cortisol + DHEAS?
placental CRH.
Effect of cortisol on placental CRH levels:
- increased placental CRH.
- positive-feedback system.
What two hormones lead to surfactant production in the fetal lungs and maturation of the fetal lungs?
Cortisol + placental CRH.
What molecule is responsible for the increase in E3 levels at the end of the third trimester?
Fetal and maternal DHEA.
What occurs when E3 > E2 levels at the end of the third trimester?
- E3 activates endometrial estrogen receptor.
- Increased contractile protein expression in myometrium.
- Myometrium contraction promoted.
What enzyme is expressed by the placenta that converts maternal DHEAS to DHEA?
steroid sulfatase
What causes contraction of the myometrium during labor (4)?
- cortisol.
- oxytocin.
- prostaglandins.
- decreased progesterone levels.
Around the time of labor, the corpus luteum begins to secrete which hormone?
relaxin.
Relaxin hormone causes (2):
- cervix relaxation (cervical ripening).
- pelvic ligament softening.
A full-term pregnancy is roughly how many weeks?
39-42 weeks
When do CRH levels peak during pregnancy?
birth
When does the myometrium stop growing, and what effect does this have?
- late mid-third trimester.
- fetal growth continues; uterine wall stretches.
- stretch-induced contraction promoted.
Preterm labor: what three drugs can be given and why?
- corticosteroids: ensures proper fetal organ development.
- tocolytic agents: inhibit calcium; halts muscle contractions.
- 17α-OHP4 (progestin): progesterone prevents muscle contractions.
5 common reasons for infertility:
- Ovulatory dysfunction (obesity; BBT).
- Uterine disorder (fibroids).
- Tubal disorder (STD).
- Peritoneal factor.
- Male factor.
What hormone is upregulated during pregnancy to promote lactation (milk production)?
prolactin.
What hormone is an inhibitor of prolactin?
dopamine.
What hormones block milk letdown (secretion) from occurring during pregnancy?
estrogen and progesterone.
Estrogen and progesterone promote the growth of what two components of breast tissue for milk production?
- Estrogen: breast ductal epithelium.
- Progesterone: breast alveoli.
What hormone stimulates the proliferation of mammary ductal epithelial cells during pregnancy?
estrogen.
What hormone promotes the growth of mammary alveoli during pregnancy?
progesterone.
What reflex develops in mothers after giving birth?
suckling reflex.
The suckling reflex is dependent on what two hormones, and for what?
- Prolactin: lactation (milk production).
- Oxytocin: milk letdown.
