Physiologic/Endocrine Changes during Pregnancy and Parturition Flashcards Preview

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Flashcards in Physiologic/Endocrine Changes during Pregnancy and Parturition Deck (53):
1

ovulation

regularly around day 15

increasing P and E from corpus luteum

2

if fertilization occurs

blastocyst hatches from zona pellucida and inplantation begins day 22-23

release of hCG

3

hCG

rescues corpus luteum

secreted from trophoblast after it attaches to endometrium

4

receptive period

day 20-24 approx

decreased antiadhesion protein and increased adhesion protein uterine endometrium

5

pregnancy duration

determined by date of last menstrual cycle

nornally aound 40 weeks
-38 weeks from ovulation

6

hormone pregnancy test

beta-hCG

can be detected 24 hours after implantation in urine

7

major hormones of pregnancy

hCG
progesterone
estrogens
hPL / hCS

8

estrogens

estradiol
estrone
estriol

9

hPL

human placental lactogen

10

hCG

important first trimester
-rescue corpus luteum

11

luteal placental shift

production of progesterone and estrogen from corpus luteum to placenta

8 weeks

very important
if doesnt occur - no pregnancy

12

2nd and 3rd trimester

progesterone and estrogen levels continue to rise

release by placenta

13

hCG

produced by syncytiotrophoblasts
half-life 30 hours

detected by pregnancy tests

may be responsible for morning system

peaks 10 weeks after implantation

double every 2 days during first 6 weeks

14

hCG structure

similar to LH, FSH, TSH - mostly LH
binds to receptors with high affinity
-maintain corpus luteum

can also bind TSH receptors
-transitional gestational hyperthyroidism

15

transitional gestational hyperthyroidism

hCG weakly binds TSH

16

other hCG actions

stimulates leydig cells > testosterone (mimics LH)
stimulates adrenal cortex

17

progesterone

increases rapidly when production switches to placenta

around 8 weeks

required to maintain a uterus - quiescent myometrium**

cannot be indicator of fetal healthy
-just placental function

18

high levels of progesterone need

CYP11A1, 3-beta hydroxysteroid DH, and maternal cholesterol

19

actions of progesterone

decreased uterus motility/contractions

increased secretions of uterus
-nourishment, growth, implantation of embryo

increased fat deposition early in pregnancy
-appetite, sugar to fat

20

estrogens

placenta takes over production around week 8

21

estrogen synthesis

require products from fetus
-19 carbon androgen (DHEA-S) from adrenal gland

can indicate fetal status

22

estriol

major estrogen of pregnancy

levels used as indicator of fetal health

23

actions of estrogen

initiation parturition
-important end of term

increased blood flow
increased smooth muscle hypertrophy
increased prostaglandins
increased oxytocin
increased mammary gland growth
increased prolactin secretion
increased LDL receptors on syncytiotropoblasts

24

estrogen:progesterone ratio

shifts later in pregnancy
-preparing for parturition

25

after parturition

decreased progesterone - allows for PRL action on breast and lactation

26

hPL

aka hCS

produced by syncytiotrophoblasts
-detected in maternal serum by 3 weeks
-rise throughout pregnancy
-proportional to placental growth

27

rises in proportion to placenta growth

hPL (hCS)

28

actions of hPL

increased glucose availability to fetus **

antagonizes insulin action
-inhibits maternal glucose uptake
-lipolytic
-stimulates mammary gland development

29

maternal-placental-fetal unit

distinct but work together

fetal health can decline with functioning placenta

non-functioning placenta always detrimental to fetus

30

placenta

site of exchange
gas, nutrients, exchange, hormones, antibodies, drugs, viruses

31

function of placenta

maintain pregnant state of uterus (progesterone)
stimulate lobuloaveolar growth of breasts
support fetal growth
regulate fetal development
regulate timing of parturition

32

P and E normal cycle vs. pregnancy

much much higher levels in pregnancy

because placenta can produce so much

33

limitations of placental

cannot make cholesterol
lacks enzymes for estrone and estradiol, estriol production

34

contribution of mother

LDL cholesterol

35

fetus contribution

3 main enzymes to produce estrogens

17 alpha hydroxylase
17,20 desmolase
16 alpha hydroxylase

36

DHEA-S

produced in fetus
-first product of the 3 enzymes of estrogens

-goes back to placenta where its converted to estrogens

37

prolactin

estrogens increases PRL release from anterior pituitary

lactotrophs hypertrophy and hyperplasia
-can increase pituitary size

38

increased pituitary size

can cause dizziness and vision problems
-optic chiasm

can be susceptible to insult and necrosis
-sheehans syndrome

39

sheehans syndrome

vascular insult and necrosis due to increased pituitary size during pregnancy

40

decreased LH and FSH

negative feedback on estrogens and progesterone

41

ADH secretion augmentation

lower set point for release
-released at lower osmolarity

threshold altered by progesterone action

42

thyroid size

increased
-stimulated by hCG
-weakly binds TSH receptors

increased total T4 and total T3**

estrogen promotes increased liver production of thyroxine-binding globulin

no change in free T4 and T3**

43

cortisol levels

increase total cortisol
-estrogen stimulate increased liver production of cortisol-binding protein

increased free cortisol
-later in pregnancy
-increased 2x by parturition

44

cortisol inactivation

to protect fetus
by placental 11-beta DH type II

45

aldosterone levels

increases dramatically

estrogen stimulates angiotensinogen and renal renin production
-ANG II and aldosterone increase

progesterone blunts aldosterone action

doesnt cause hypernatremia, hypokalemia, HTN

46

woman with normal BMI

25-35 lb increase with pregnancy

30 lbs, 10 lbs fat, 1.5 lb uterus, 4.5 lb breasts, 1.5 lb placenta, 2.2 lb amniotic fluid, 2 lb maternal blood, 7 lbs fetus

47

cardiovascular changes during pregnancy

increased blood volume

increased CO

decreased TPR

decreased MAP (or remains same )
-balance between CO and TPR

48

MAP = ?

CO x TPR

49

hematocrit

increased during pregnancy

50

increased blood volume

increased 45% near end of pregnancy

adequate fetal perfusion and exchange
protects mother blood loss during delivery

51

cause of increased blood volume

increased plasma volume
-increased NaCl retention
-stimulated by estrogen

increased water retention and intake
-lower threshold for ADH/AVP and thirst during pregnancy
-increased sensitivity to osmoreceptors

52

hematocrit changes

decreased
-physiological anemia

RBC production can't keep up with plasma increase

decreased viscosity, decreased TPR
-helps minimize maternal cardiac work

53

hematocrit effect

decreased viscosity of blood