Endocrinology of Parturition

Question 1

What is the mean duration of human singleton pregnancy?

Answer 1

280 days or 40 weeks from the first day of the last normal menstrual period

Question 2

What is meant by “Term”?

Answer 2

Period from 37 to 42 weeks

Question 3

What is meant by “Preterm”?

Answer 3

Delivery before 37 weeks

Question 4

What is meant by “Post-term”?

Answer 4

Pregnancy beyond 42 weeks

Question 5

Four phases of pregnancy:

Answer 5

Phase 1: Quiescence
Phase 2: Activation
Phase 3: Stimulation
Phase 4: Involution

Question 6

Where is the majority of relaxin produced during pregnancy?

Answer 6

Corpus luteum

Question 7

Which hormones play a role in phase 1?

Answer 7

P4
Relaxin
hCG
CRH
NO

Question 8

Which hormones play a role in phase 2?

Answer 8

E3
P4
Ferguson reflex
CRH
Relaxin
PGE

Question 9

Which hormones play a role in phase 3?

Answer 9

PGE
OT
Relaxin
CRH
Inflammatory reaction
Surfactant Protein A

Question 10

Which hormones play a role in phase 4?

Answer 10

OT

inflammatory reaction

Question 11

How do estrogen and progesterone act in myometrial quiescence?

Answer 11

Through an increase in cGMP

Question 12

Three major effects of prostaglandins:

Answer 12

1. ) Stimulate uterine contraction
2. ) PGF2alpha promotes formation of gap junctions between uterine SM cells for contractions
3. ) Ripens, dilates, thins the cervix

Question 13

What does PGE2 and PF2alpha do?

Answer 13

PGE2: dilates cervical blood vessels and leads to cervical ripening
PF2a: increases total GAGs activity

Question 14

What occurs in phase 2?

Answer 14

Increased OT receptors

Estrodiol increased

Question 15

Increased levels of CRH in phase 2 leads to what?

Answer 15

Fetal cortisol stimulation of prostaglandin synthesis

Question 16

What is responsible for fetal lung maturation?

Answer 16

Glucocorticoids

Question 17

How can CRH induce spontaneous labor?

Answer 17

CRH stimulates fetal ACTH release stimulating GC production; once CRH stops GC production it means the babies lungs are ready and labor inducing forces begin

Question 18

Two way oxytocin induces uterine contractions:

Answer 18

1. ) Stimulates release of PGE2 and PF2a by activation of PLC
2. ) Directly causes myometrial contractions through PLC -> Ca2+ intracellularly

Question 19

What is puerperium?

Answer 19

From delivery of placenta through first few weeks after delivery (6 weeks)

Question 20

Repair processes post-partum occur in what three phases?

Answer 20

Immediate: 24 hours
Early: 7 days
Remote: 6 weeks

Question 21

What contributes to postpartum depression?

Answer 21

Precipitous drop in estrogen and progesterone

Question 22

Effect of P4 on milk production?

Answer 22

Suppress milk production during pregnancy by inhibiting PRL

Question 23

Most important galactopoietic hormone?

Answer 23

Prolactin

Question 24

Most important galactokinetic hormone?

Answer 24

Oxytocin

Question 25

What is the milk ejection reflex?

Answer 25

Stimulation by nipple sucking sends signals to the hypothalamus to release OT from posterior pituitary where it bind smooth muscle in mammary glands and they contract

Question 26

Four stages of lactation:

Answer 26

Stage I: Mammogenesis-preparation of the breasts Stage II: Lactogenesis- synthesis and secretion of milk Stage III: Galactopoiesis- maintenance of lactation Stage IV: Involution- return to non-lactating breasts

Question 27

When does mammogenesis occur?

Answer 27

12 weeks before delivery; colostrum is present the first rich milk

Question 28

When does lactogenesis occur?

Answer 28

2-3 days after birth when the milk comes in; P4 drops PRL stays high

Question 29

What is the organization of secretory tissue in breast?

Answer 29

Alveolus organized into lobules which drain into ductules which widens at the ampulla and drain into the lactiferous duct

Question 30

What is contained in colostrum?

Answer 30

Protein and minerals (low in carbs/fats) Antibodies to for passive immunity Laxative for first bowel movements

Question 31

What is galactopoiesis?

Answer 31

Production of milk; a supply and demand system

Question 32

Effects of lactation on GnRH?

Answer 32

Inhibits GnRH release and therefore release of FSH and LH and the ovarian cycle is inhibited

Question 33

Medications that improve milk production?

Answer 33

Metoclopramide Sulpurude Intranasal oxytocin

Question 34

How does metoclopramide work?

Answer 34

Increases PRL levels

Question 35

How does sulpurude work?

Answer 35

Dopamine antagonist

Question 36

Drugs to suppress lactation?

Answer 36

Bromocriptine

Question 37

How does Bromocriptine work?

Answer 37

Dopamine agonist