Repro 5 - Pregnancy and Parturition Flashcards
Hormone that inhibits uterine contractions
Relaxin
Relaxes pelvic bones/ligaments, softens cervix
Relaxin
Significant lactation is inhibited by high levels of these
Estrogen and progesterone
Main cholesterol source for placenta
Maternal LDL
Major site of estrogen synthesis during pregnancy
Placenta
Esp. the fetal zone of the fetal adrenal gland
The fetal adrenal gland may be this big during pregnancy, as compared to normal ratio to height
20x
Less bioactive form of DHEA
DHEA-S
Process by which the placenta makes estrone and estriol
Removing the sulfate from DHEA-S
Marker for fetal well-being
Estriol (made only from fetal liver precursors)
This hormone Inhibits uterine contractions and prostaglandin production
Progesterone
Upregulates alpha-adrenergic receptors that promote myometrial relaxation
Progesterone
Stimulates alveolar pouches in breast to produce milk
Progesterone
Ratio that maintains uterine quiescence, sustenance of fetus
Progesterone»_space; Estrogen
Ratio that promotes parturition
Estrogen»_space; Progesterone
Hormone in contraceptives that prevents LH secretion
Progestional hormone
Hormone in contraceptives that prevents FSH release
Estrogen
Changes in maternal cardiac output and TPR
CO goes up
TPR goes down
*TPR goes down more than CO goes up, so mean arterial pressure decreases
Amount of blood flow that reaches uterus
30%
Respiratory changes during pregnancy
Increase in tidal volume, no change in frequency
Functional hyperventilation leads to respiratory alkalosis, which is then offset by increased bicarb excretion
Any change in GI tract during pregnancy?
GI motility slows, allowing for more time for nutrient absorption
Also a decrease in LES tone, resulting in potential heartburn for the mother
Maternal metabolic state during first half of pregnancy
Anabolic
Normal or increased sensitivity to insulin
Increased fat and glycogen stores
Promotes growth of breast tissue (“stockpiling” nutrients for fetus)
Maternal metabolic state during second half of pregnancy
Accelerated starvation state
Insulin resistance (pregestational diabetes is common)
Mediated by hCG
Hormone that peaks during parturition, related to contracture response to prostaglandins and oxytocin
CRH (cortisol releasing hormone)
increases E2. Fetal cortisol amplifies placental CRH synthesis (localized positive
feedback)
Term for false contractions
Braxton-Hicks
This hormone increases the number of OT receptors in endometrial tissue, increasing sensitivity
Estrogen
Uterus sensitivity to estrogen (timeline)
0-20 weeks: insensitive
20-36 weeks: gradually increases to 80x
during labor: 200x
Signal for the distension of the cervix
Ferguson reflex
Does OT promote or inhibit prostaglandin release?
Promote (promotes contractions
Alpha adrenergic receptors for catecholamines in myometrial contraction
Increase contractions
Beta adrenergic receptors for catecholamines in myometrial contraction
Decrease contractions
E2 and prostaglandins increase which adrenergic receptors?
Alpha adrenergic receptors
Colstrum vs normal human milk
More protein, less fat, more cells
Essential factors for continued milk production (3)
Prolactin, cortisol, insulin
Stimulates breast for milk ejection (“letdown”)
Oxytocin
Mechanism for milk production
Afferents from spinal cord inhibit dopamine release from arcuate nucleus, removing the tonic inhibition of prolactin. This leads to increased levels of prolactin and milk production
(also causes a decrease in GnRH)
