Montemayor-pregnancy and parturition Flashcards
1
Q
What day does fertilization usually occur
A
day after ovulation
average day 16
2
Q
When does implantation occur after ovulation
A
6 or 7 days later
3
Q
how long is pregnancy from last menstrual cycle
“gestational period”
A
40 weeks
4
Q
how long is pregnancy from ovulation
“embryonic”
A
38 weeks
5
Q
What is detected in pregnancy test
A
beta hCG
detected 24 hrs after implantation
6
Q
What are the 4 types of estrogens
A
estradiol, estrone, estriol
7
Q
What are the major hormones of pregnancy
A
hCG, progesterone, estrogens, human placental lactogen/human chorionic somatomammotropin
8
Q
What hormones play a role in the 1st trimester
A
hCG savs corpus luteum to stimulate luteal estrogen and progesterone production
placenta takes over hormone synthesis
9
Q
What time frame does the placenta take over hormone synthesis from corpus luteum
A
8 weeks “luteal placental shift”
10
Q
What hormones play a role in the 2nd trimester
A
maternal progesterone and estrogen levels rise
maternal placental fetal unit takes over production
11
Q
What produces hCG
A
syncytiotrophoblasts
12
Q
when does hCG peak
A
around 10 weeks to make sure that the luteal placental shift occurs
13
Q
Structurally hCG is similar to what other hormones? so which R can it bind
A
LH, FSH and TSH
binds LH R with high affinity
14
Q
what is the primary action of hCG
A
stimulate LH R on corpus luteum
prevents degradation
maintains high luteal-derived progesterone before placenta takes over
15
Q
what are the other effects of hCG
A
can cross react with TSH R and cause hyperthyroidism
stimulates fetal leydig cells to produce testosterone
stimulates fetal adrenal cortex
16
Q
When does the P production increase
A
switch from corpus luteum to placenta
17
Q
What hormone is needed to maintain pregnancy and why
A
P because inhibits myometrial contractions. (sm muscle inhibitor)
18
Q
Can progesterone be used as indicator of healthy fetus
A
no, independent
just tells how well the placenta is functioning
19
Q
What other substances are needed to make progesterone
A
CYP11A1 and 3beta hydroxysteroid dehydrogenase to convert cholesterol derivative to progesterone
20
Q
What are the action sof progesterone in pregnancy
A
dec uterine motility/contractions
increase secretory activity necessary for nourishment, growth, and implantation of embryo
increase fat deposition early in pregnancy(stimulate appetite, diver energy stores from sugar to fat)
21
Q
Where are estrogens made during pregnancy
A
placenta after luteal switch
22
Q
Can estrogen during pregnancy be maintained by mother alone
A
no need 19 C androgen DHEA-S from fetus (adrenal gland)
23
Q
What estrogens is the fetus placental unit responsible for
A
estradiol-17Beta
estrone
estriol(major)
24
Q
Can estrogen be used as an indicator for fetal health
A
yes, estriol is used as measurement
25
What are the actions of estrogens in pregnancy
```
increase uteroplacental blood flow
increase uterine sm mm hypertrophy
increase LDL R expression
increase PG
increase oxytocin R
increase mammary gland growth
increase prolactin
```
required for parturition
26
how do E:P levels change throughout pregnancy
low E:P to high E:P
27
What produces human placental lactogen
syncytiotrophoblasts in placenta
28
What is human placental lactogen a direct proportion to
placental growth (weight)
29
What is the main role of hPL
increase glucose availability for fetus
inhibits maternal glucose uptake
lypolytic action--> shift maternal energy use to FFA
30
What are the other roles of hPL and what is it responsible clinically in pregnant mother
antagonize insulin action "diabetogenicity of pregnancy"
| stimulates mammary gland development
31
With a functioning placenta, can fetal health decline? nonfucntioning?
functioning, fetus can still decline
| non-functioning, always detrimental
32
What do syncytiotrophoblasts produce
steroid and protein hormones
33
What are the functions of placenta
maintain pregnant state of uterus
stimulate lobuloalveolar growth and function of breasts
adapt aspects of maternal metabolism and physic to support fetus
regulate aspects of fetal development
regulate timing and progression of parturition
34
What are the limitations of the placenta
cannot make enough cholesterol
lack enzymes for estrone and estradiol production
lacks enzyme for estriol production
35
What does the mother contribute to placenta for adequate hormone production
LDL cholesterol
36
What does the fetus contribute to placenta for adequate hormone production
the enzymes to make estrone, estradiol and estriol
37
What enzyme does the placenta have for produce estrogens
the aromatase to convert DHEA to estradiol
38
What changes in the pituitary in the mother during pregnancy
increase prolactin
increase pituitary size
dec LH and FSH
ADH secretion threshold is augmented
39
What happens to the lactotrophs during pregnancy? what causes this?
increase in size and number
| estrogen stimulates PRL synthesis and secretion
40
If the pituitary becomes too big and causes vascular problems what is that called
Sheehan's syndrome
41
Why does LH and FSH production decrease during pregnancy
neg feedback from estrogens and progesterone
42
What happens to ADH threshold in pregnancy
ADH is released at a lower osmolality (lower threshold)
higher ADH levels than usual
increased sensitivity of osmoR
43
What are the changes to thyroid in pregnancy
increase thyroid size
| increase total T4 and total T3
44
What is though to cause increase in thyroid size during pregnancy
stimulated by hCG
| weakly binds TSH R- transitional gestational hyperthyroidism
45
Why are there increased total T4 and T3 in pregnancy but no changes in the Free T4
estrogen promotes increased liver production of thyroxine binding globulin
46
What are the adrenal changes during pregnancy
increased cortisol, aldosterone
47
Why is there an increase of cortisol during pregnancy
estrogens stimulate, increase liver production of cortisol-binding globulin
48
Why is there and increase in free cortisol
late in pregnancy, because inactivated to protect fetus by placental 11betadehydrogenase type 2
49
Why does aldosterone increase during pregnancy
estrogens stimulate increase liver production of angiotensinogen and renal renin production
increase ang II and aldosterone
50
How come the increased aldosterone does not result in hypernatremia, hypokalemia or hypertension
progesterone blunts aldosterone action
| competes for mineralocorticoid R
51
What are the CV changes during pregnancy
increase blood volume, dec hematocrit
increase CO thru inc HR and SV
decrease TPR, inc vasodilation and vascularity with a dec in hemtocrit
dec MAP or normal
52
Why does MAP relatively stay fairly normal during pregnancy
increase CO
| decrease TPR
53
Why is there an increased blood volume in pregnancy
facilitates fetal perfusion and exchange of nutrients/wastes
| protects mom from blood loss during delivery
54
What causes the increase in plasma V in pregnancy
increase NaCL retention from aldosterone
| increase H2O retention from low ADH threshold
55
Why does hematocrit dec during pregnancy (physiological anemia)
what is overall result
increase RBC production rate does not match the plasma expansion
decrease viscosity so decrease TPR
56
What is the effect of decreased TPR on maternal cardiac work
minimizes maternal work as CO increases
57
by how much does CO increase during pregnancy
30-50% by inc HR and SV
58
Why does SV decrease in late pregnancy
SV periodically dec due to compression of the IVC
| decrease VR, decrease EDV and decrease SV
59
Where does the additional CO distribute to
uterus 15% of CO
| increase renal by 40%
60
What systems of the body do not change during pregnancy
brain, gut, skeleton
61
Describe the 2 ways there is an overall decrease in TPR in pregnancy
low resistance circuit utero/placental circulation from vasculogenesis and angiogenesis
Vasodilation from E and P
62
How does E and P cause vasodilation
antagonists to vasopressive action of ANG II
| P acts as smooth m relaxant
63
How come there is an increase in venous P in pregnancy
compression of IVC from growing uterus
| increased venodilation under hormonal influences
64
What causes the decreased capillary colloid osmotic pressure in pregnancy
maternal synthesis of plasma proteins does not keep pace with increase in plasma volume
65
What factors contribute to the increase in alveolar ventilation
elevation of diaphragm
increased O2 demand and CO2 production
increased sensitivity to CO2
66
What causes an elevated diaphragm in pregnancy
increased intra-abdominal P with fetal growth
Progesterone effect of relaxing m and fascia
decrease residual volume and functional residual capacity
67
Why is there an increased sensitivity to CO2 in pregnancy
progesterone effect
dec medullary resp center set-point for respiratory response to central chemo R detection of CO2
increased tidal volume and alveolar ventilation
decrease partial pressure of CO2
68
What are all the respiratory changes in pregnancy
```
dec functional residual capacity
decrease residual volume
increase tidal volume
increase alveolar ventilation
no change in RR
decrease PCO2
```
69
Can pregnancy cause respiratory alkalosis or acidosis
dec PCO2 so respiratory alkalosis
70
What occurs in response to the respiratory alkalosis in pregnancy
renal compensation to increase HCO3 excretion
71
Describe the fetal hemoglobin compared to adult
has higher affinity for O2 than mom
| lower CO2 affinity
72
What are the renal changes in pregnancy
increased blood flow, GFR
increases plasma RAAS from Estrogen
increase Na retention from aldosterone
increase H2O retention from dec ADH threshold
decrease serum Na from dec in ADH threshold
73
What GI changes in pregnancy cause reflux
dec in gastric emptying from Progesterone
dec in LES tone from Progesterone
increase intra-abdominal P
74
What Gi changes in pregnancy causes constipation
decrease in intestinal motility
75
What are the 3 demanded nutrients in pregnancy
protein, iron and folate
76
What is the purpose of increase protein demand in pregnancy
supports fetus, placenta, uterus, breasts, blood volume
| additional 30 g protein/day
77
What is the purpose of increase iron demand
suppor increased maternal Hb, placenta and fetus
| 60mg/day supp recommended
78
What is the purpose of increase folate demand
supports increased RBC production, protects against neural tube defects
400-800 mg/day folic acid supplementation recommended
79
What keeps the uterus from contracting during pregnancy
progesterone and relaxin
80
What initiates onset of labor
endocrine and paracrine and mechanical factors
81
What keeps labor going
positive feedback loops
82
What are the Braxton Hicks Contractions
periodic episodes of weak, slow rhythmic contractions
very strong during last hours
become labor contractions
83
What is false labor, and what could cause it
contraction begin strong then fade
| failure of +feedback loops
84
What is the + feedback loop
afferent pain signals from uterine contractions reflexively result in abdominal m contraction
85
How many stages of labor are there
4
| the first or stage 0 is just quiescent phase
86
Describe stage 1 of labor
cervical dilation and effacement
contractions go from 30 min to <10 min apart
lasts average 7-12 hours
87
Describe stage 2 labor
Descent and expulsion
active labor, cervix fully dilated to 10 cm
contractions
lasts 20-50 minutes
88
Describe stage 3 labor
expulsion of placenta
uterus contracts which limits bleeding because compresses vessels
separation of placenta results in bleeding and clotting
average 15 minutes
89
What endocrine factors are important in parturition
```
PGs
Estrogens
Oxytocin
Placental Corticotropin releasing hormone
relaxin
```
90
What are the PGs involved in birth, what do they do
PGF2alpha and PGE2
initiate birth because increase before onset of labor
increase uterine smooth m contractility promotes gap junctions
soften, dilate and thin cervix
91
What stimulates synthesis of PGs
estrogens, oxytocin
| uterine stretch
92
How does estrogen stimulate PG synthesis
```
Phospholipase A2
PG synthetase (COX)
```
93
What is used to induce labor in large doses
PGs
94
What inhibits labor clinically
aspirin, reduces PGF2alpha and PGE2
95
What is the role of estrogen in parturition
inc gap juntions
inc oxytocin R expression
inc myometrial sensitivity to oxytocin
inc PH production
96
What is the role of oxytocin in birth
maintain labor- distention of cervix
increased 200X R expression during early labor
R activation promotes uterine smooth m contraction
stimulate PGF2alpha synthesis
97
Where is oxytocin released form and what causes it
released from posterior pituitary
caused by neurogenic reflex (ferguson), response to stretching of cervix, bursts of oxytocin released during stage 1 and frequency then increases
98
How does oxytocin increase uterine sm m contractions
PLC to IP3 to increase intracell Ca that activat calmodulin which inc MLC kinase to Pi regulatory light chain for contraction
99
Why are uterine contractions important after placental delivery
to constrict vessels after placental delivery
100
What is the role of corticotropin-releasing hormone CRH
sensitizes uterus to PG and oxytocin
| stimulate fetal ACTH
101
Why is it important that CRH stimulates fetal ACTH
increase fetal adrenal cortisol (+ feedback to CRH)
| increase fetoplacental estrogens
102
What is the role of relaxin in parturition
soften cervix during labor because does promote myometrial quiescence, but also increases during labor
103
What factors from the fetus are important in birth
fetal pituitary oxytocin
fetal PG from placenta
fetal androgens, cortisol
104
What fetal and placental signals prepare for labor
CRH from placenta, causing increased fetal ACTH and cortisol and DHEAS and estrogen
CRH promotes contractions by sensitizing uterus to PG and oxytocin
105
What is the role of estrogens in labor
stimulate contractions as well
106
What are the mechanical factors to increase uterine contractility
```
stretch of sm m causes contraction
fetal movement
(twins are born earlier)
contractions increase PG production
ferguson- inc stretch of cervix stimulating more oxytocin
```
