Physiology of Pregnancy and Lactation Flashcards by S B

what is the timeline for fertilised embryo moving into the uterus

day 1 = fertilisation in ampulla
day 3-5 = transport of blastocyst into the uterus
day 5-8 = blastocyst attaches to lining of uterus

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what do the inner cells of the blastocyst develop into

the embryo

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what are the outer cells of the blastocysts and what do they do

trophoblastic cells

penetrate the endometrium and burrow into the uterine wall
will become the placenta

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how long does it take for the trophoblastic cells to burrow deep enough for the blastocyst to become buried in uterine lining

12 days

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what is the placenta derived from

trophoblast and decidual [endometrium] tissue

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how are placental villi’s formed

Trophoblast cells differentiate into syncytiotrophoblast&raquo_space; invade decidua&raquo_space; break down capillaries&raquo_space; form cavities filled with maternal blood

Developing embryo sends capillaries into these projections&raquo_space; placental villi’s formed

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by when is the placenta [and foetal heart] functional by

5th week of pregnancy

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where does the early nutrition of the embryo come from

the invasion of trophoblastic cells into the decidua

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what is the role of HCG in the nutrition of the embryo

signals the corpus luteum to continue secreting progesterone&raquo_space;> stimulates decidual cells to concentrate glycogen, proteins and lipids

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what does the placenta essential work as

physiological arteriovenous shunt

- due to circulation within the intervillous space between mother and foetus blood

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what is another key role of the placenta

plays as role as fetal lungs

Oxygen diffuses from the maternal into the fetal circulation system
CO2 follows reverse gradient

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how does Fetal, oxygen saturated blood return to the fetus

via the umbilical vein

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how does maternal, oxygen-blood blood return to the mother’s circulation

via uterine veins

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what 3 factors facilitate oxygen transport in fetus blood

fetal Hb - increased ability to carry O2

higher Hb conc in fetal blood

Bohr effect - Fetal Hb can carry more oxygen in low pCO2 than in high pCO2

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how does water and electrocytes diffuse across the placenta

water diffuses along osmotic gradient

electrolytes follows water

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what are the only electrolytes that can go from mother to child

iron and calcium

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how does glucose get across the placenta

simplified transport

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what role does HCG have in fetal development

effect on the testes of male fetus - development of sex organs

prevents corpus luteum degrading

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from when is HCS produced

around week 5 of pregnancy

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what effects does HCS have

growth hormone-like effects: protein tissue formation.

decreases insulin sensitivity in mother: more glucose for the fetus

involved in breast development

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what is the function of progesterone

development of decidual cells

decreases uterus contractility

preparation for lactation

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what is the function estrogens

enlargement of uterus

breast development

relaxation of ligments

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what is an indicator of vitality of the foetus

estriol level

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what affect does the placenta releasing CRH have on the mother

increases ACTH
» increases aldosterone
» increases cortisol

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what does the increase in aldosterone cause

hypertension

what does the increase in cortisol cause

oedema insulin resistance >> gestational diabetes

what affect does the placenta releasing HCG have on the mother

hyperthyroidism

what affect does the placenta increasing calcium demands have on the mother

hyperparathyroidism

what are cardiovascular maternal changes seen in pregnancy

Increase in CO [due to demands of fetal circulation] HR increases BP drops during 2nd trimester

where does CO normally sit in pregnancy

30-50% above normal | - beginning week 6 gestation and peaking around 24 weeks

what are all normal changes seen in pregnancy in the mother - in relation to the heart

ECG changes functional murmurs heart sounds

how does CO change in the last 8 weeks of pregnancy

decreases as uterus compresses vena cava

what can the HR increase up to in pregnancy

90/min

what are haematological changes seen in pregnancy

plasma volume increases proportionally w/ CO erythropoesis (RBC) increases >> Hb decreases by dilution iron requirements increases >> supplements may be needed

what causes resp changes seen in pregnancy

increasing progesterone enlarging uterus increasing O2 consumption

how does progesterone affect resp

signals the brain to lower CO2 levels

how does the body work to lower CO2 levels

RR increases Tidal volume increases pCO2 decreases slightly Vital capacity and PO2 don’t change

what urinary changes are seen in pregnancy

GFR and renal plasma flow increase

when does the increase in GFR and renal plasma flow increase

@ 16-24 weeks

how can postural changes affect renal function

upright position decreases supine position increases lateral position increases

what is pre-eclampsia

pregnancy induced hypertension + proteinuria

what leads to the proteinuria

Kidney function declines: salt and water retention - oedema formation (esp hands and face) Renal blood flow and GFR decreases

what is the single most significant risk of getting pre-eclampsia

having had pre-eclampsia previously

what are other RF for pre-eclampsia

``` pre-existing hypertension, diabetes autoimmune diseases (eg lupus) renal disease FHx of pre-eclampsia obesity women with a multiple gestation (twins or multiple birth) ```

what are SX of eclampsia

vascular spasms, extreme hypertension, chronic seizures & coma

what is the Tx of eclampsia

vasodilators and c-section

what is the average maternal weight gain

24lbs

what causes insulin resistance in pregnancy

HCS cortisol growth hormone

what is the special nutritional needs in pregnancy

``` high protein iron supplements vitamin B folic acid Vit D3 + Ca2+ supplements ```

what is given before labour to prevent intracranial bleeding

Vitamin K

what is parturition

birth of baby

how does the Estrogen:Progesterone ratio help in labour

progesterone inhibits contractility while estrogen increases contractility.

where is oxytocin made

maternal posterior pituitary gland

what is the function of oxytocin

increases contractions and excitability

what are Braxton Hicks contractions

sporadic uterine contractions

what does cervical stretching cause

further oxytocin release

what effect does oxytocin have on the placenta

stimulates it to make prostaglandins which stimulate more vigorous contractions of the uterus

what are the 3 stages of labour

1st stage: cervical dilation (8-24 hours). 2nd stage: passage through birth canal (few min to 30 min). 3rd stage: expulsion of placenta.

what inhibits milk production

oestrogen | progesterone

what stimulates milk production

prolactin

what does oxytocin do

causes smooth muscle contraction so milk is ejected