Physiological Adaptations to Pregnancy

Question 1

Pregnancy - Key stages

What are the 2 stages of the first trimester (3 months) of pregnancy and at what weeks do they occur?

Answer 1

Weeks 1-12 Preembryonic
At Weeks 3-8 (included in preembryonic): embryonic

think embryo

Question 2

What are 4 stages of the second trimester and at what weeks do they occur?

think fetus

Answer 2

Weeks 13-26: fetal development

At weeks 9-40 (included in fetal development): fetal period

At week 24 (included in fetal development): viability (fetus can be born at this age and survives)

Question 3

What are the 2 stages of the third trimester of pregnancy

Answer 3

week 27-40: maturation
week 38-42: delivery

Question 4

first signs

What are the 5 first signs of pregnancy?

think sickness, missing period, breasts, tired, wanting to eat food

Answer 4

Nausea: caused by endocrine (hormonal) changes
Amenorrhoea: missed period
Breast tenderness: increased production of steriod hormones
Fatigue
Food cravings (PICA): more sensitive sense of smell

Question 5

first signs

what is hyperemesis gravidarum and what is it treated with?

think sickness and what drug is used to treat it and type of administration

Answer 5

extreme form of nausea: treated with antiemetics via tablets (short term symptoms) or injections (prolonged symptoms)

Question 6

weight gain during pregnancy

Outline the constituents and their amount of weight gain during pregnancy in: 1. maternal, 2. fetus

think myometrium, fat and blood for maternal

think placenta, amnoitic fluid and fetus for Fetus

Answer 6

Maternal:
- myometrium (0.9kg)
- fat (4kg)
- blood (1.2kg)

Fetal:
- Placenta (0.7kg)
- amniotic fluid (0.8kg)
- fetus (~ 3.3kg)

Question 7

Weight gain

Outline 4 essential nutrients for pregnancy

Answer 7

• folic acid (pre-pregnancy)
• iron
• vitamin K
• Vitamin B

Question 8

spiral artery remodlling

Why does the spiral artery get remodelled?

Answer 8

To maximise blood flow to the baby

Question 9

spiral artery remodelling

outline how spinal artery remodelling occurs, what brings it about and what the results of it are.

for first part, think decidual spiral arteries and vascular cells, size of arteries and result of this

for second part, think what immune cells bring spiral artery remodelling about

for third part, think about what material is in the remodelled vessel and what it replaces and also what happens subsequently

Answer 9

1. unremodelled decidual spiral artery changes structure by losing vascular cells
2. this increases the size of the arteries, making the arteries high-flow, low resistance vessels.
3. these changes are brought by maternal immune cells (dNK cells and macrophages) and completed by invading interstitial and endovascular EVT (extravillous trophoblast).
4. the remodelled vessel consists of trophoblasts embedded in a fibrinoid material as a replacement for the layer of VSMCs (vascular smooth muscle cells).
5. subsequent re-endothelialisation occurs later in pregnancy

Question 10

anatomical changes in pregnancy

Outline 6 anatomical/structural changes in pregnancy

think endometrium and uterine arteries, diaphragm, heart and bladder, myometrial cells and what happens to them, what the cervix does, and mucus and what this does. ** mneumonic: IFDMCM**

Answer 10

• **invasion **of endometrium & uterine arteries by trophoblast
• **formation **of placenta

-** displacement **of diaphragm, heart and bladder by growing fetus

• **myometrial **cells undergoing hyperplasia and hypertrophy
• cervix stays firm and non-compliant
• **mucus **plug maintains closed uterine environment

Question 11

pigmentation and skin changes in pregnancy

What are 2 different pigmentation/skin changes in pregnancy and why do they occur?

think melanin and nigra and think stretch marks and collogen and skin distension

Answer 11

Melasma/chloasma and linea nigra:
- caused by prodution of melanocyte stimulating hormone by oestrogen

striae:
- caused by thinning of collagen fibres and skin distension

Question 12

maternofetal transfer

True or false? Maternal and fetal blood mix

Answer 12

False, they do NOT mix

Question 13

maternofetal transfer

how do nutrients get from the maternal blood to the fetal blood

think chorionic villi

Answer 13

via chorionic villi in close contact with maternal blood

Question 14

maternofetal transfer

what is the placenta permeable to that can cause issues with fetal development

think drinking, injecting drugs, vaping and coffee

Answer 14

permeable to:

alcohol (fetal alcohol syndrome)
heroin
nicotine
caffeine

Question 15

uteroplacental bloodflow

At 20 and 40 weeks, what is the maternal blood flow through the placenta

Answer 15

@20 wks: 300ml/min

@40 wks: 600ml/min

Question 16

placental function

what are the 5 main functions of the placenta

think gases and nutrients, waste products, fighting infection, hormones and support of something

Answer 16

• nutrient and gas transfer
• transfer of waste products
• immune protection
• steriod and peptide hormone production
• support for fetus

Question 17

placental function

how does the placenta fulfil its role in nutrient and gas transfer?

think O2 and CO2 and think Glucose

Answer 17

• Gaseous exchange by passive diffusion
• glucose passes the placenta via facilitated diffusion (glucose transporters) to get to the fetus

Question 18

placental function

why is the mother considered to be in a state of insulin resistance when pregnant and what hormone causes this?

think about what energy source the baby needs from the mother, and think about a hormone and what it does to create this maternal insulin resistance

Answer 18

• considered this because baby needs so much of the glucose from mother
• a hormone called HPL breaks down all fatty acids from mother to make them available for the fetus, creating the maternal insulin resistance

Question 19

placental function

how does the placenta have immune function?

think a particular immunoglobulin and what it does when it is near the placenta

Answer 19

IgG crosses the placenta to act as an immune system for the fetus as fetus has no immune system

Question 20

Placental function

what steroids and peptide hormones are producted in the placenta?

Answer 20

• Steriods
• hPL
• hCG
• relaxin
• leptin

Question 21

placental function

how does the placenta provide support for the fetus?

think amnion, amniotic fluid, umbilical cord

Answer 21

1. via amnion: strong membrane and expands to accommodate fetus
2. Via amniotic fluid: provides cushioning for fetus and movement
3. via Umbilical cord: allows for attachment to the mother

Question 22

Placental function

how are amino acids, water-soluble vitamins, calcium and iron transported from the mother to the fetus across the placenta

Answer 22

via active transport using system A

Question 23

Main function of Sex steroids

Outline the 5 main functions of oestrogen in pregnancy

think uterine growth, cardiovascular changes, ductal development and connective tissues

Answer 23

• Stimulate uterine growth through endo/myometrium
• Initiates cardiovascular changes
• Promotes ductal development in breast
• Effects connective tissues like cervix

Question 24

main function of Oestrogen in pregnancy

what is the most important oestrogen in pregnancy involved in all main roles of oestrogen?

Answer 24

oestriol (90%)

Question 25

# main function of Progesterone in pregnancy what are 7 main functions of progesterone in pregnancy

Answer 25

- important in implantation and the maintenance of pregnancy - decidualization of endometrium - uterine quienscence - relaxant effect of musculoskeletal system - respiratory changes - promotes alveolar development in breast

Question 26

# main functions of progesterone in pregnancy how is progesterone involved in uterine quiescence? ## Footnote think polarisation

Answer 26

progesterone levels keep the uterus hyperpolarised

Question 27

# Other hormones of pregnancy what 4 places is relaxin produced and what does this hormone do? ## Footnote think ovaries, layer beginning with d where endometrium once was, a layer in the blastocyst beginning with T and what the fetus is surrounded by (for the first part) for the second part, think about the name of the hormone.

Answer 27

produced in: - corpus luteum - decidua - trophoblast - fetal membranes - causes uterine relaxation and softening of muscular skeletal system like pelvic bone (to make it easier for a mother to deliver)

Question 28

# other hormones in pregnancy where is Human chorionic gonadotrophin (bhCG) produced and what is its function ## Footnote think the splitting of the trophoblast into 2 layers, but the one beginning with S for first part for second part think part of the ovaries and immunity

Answer 28

- produced in syncytiotrophoblast - maintains corpus luteum and provides immune tolerance

Question 29

# other hormones of pregnancy where is human placental lactogen (hPL), Oxytocin and Prolactin produced and what are their functions? ## Footnote for hPL: - think trophoblast layer splitting into 2 but the one that begins with S for production -think breasts and glucose uptake for function for Oxytocin: - think where in pituitary gland for production - think about the uterus for function for Prolactin: - think where in the pituitary gland and also think of the word "decide" for production - think amniotic fluid, what needs to be maintained in amniotic fluid and fighting infection for function

Answer 29

hPL: - produced syncytiotrophoblast - involved in breast development and inhibits maternal glucose uptake Oxytocin: - produced in posterior pituitary - acts to cause uterine contractions Prolactin: - produced in anterior pituitary and decidua - involved in amniotic fluid genesis, maintaining its osmolarity and volume, and also involved in immunity

Question 30

# haematological changes in pregnancy by what percentages does plasm volume increase during pregnancy and why does this occur? ## Footnote think nutrients for second part

Answer 30

- 40%-50% increase in plasma volume --> increases nutrient delivery

Question 31

# haematological changes in pregnancy why does total haemoglobin decrease overall in pregnancy, what is the name of this phenomenon and what can this cause in pregnancy women?

Answer 31

it decreases because although reythrocyte number increases, it is still less than plasma volume. - name for this is haemodilution - can cause amnemia in pregnant women

Question 32

# haematological changes what type of state is pregnancy in regards to blood and what is up regulated in this?

Answer 32

- hypercoagulable state Clotting factors are upregulated such as: - thrombin - fibrinogen - factor VII --> X

Question 33

# blood pressure changes why does blood pressure decrease in pregnancy?

Answer 33

due to decrease total peripheral vascular resistance

Question 34

# respiratory system changes what is the main hormone that causes respiratory system changes and what does it act on and what does it do to the ribcage to allow the diaphragm to widen ## Footnote think about medulla oblongata and what the hormones acts on in it for second part like softening things and increasing diameter

Answer 34

- progesterone - acts on respiratory centres in the medulla oblongata - progesterone (and relaxin) cause the ribcage to soften and flare out, increasing space for the diaphragm

Question 35

# Renal system changes what happens regarding urine due to progestorone? ## Footnote think ureters and renal pelvis, what this causes and pyelonephritis

Answer 35

- dilatation of ureters and of renal pelvis, causing urinary stasis, increasing pyelonephritis risk

Question 36

# renal system changes in pregnancy why would you see edema in pregnant women? ## Footnote think Na+ and RAAS

Answer 36

because of increases tubular reabsorption and retention of Na+ in the RAAS system

Question 37

# GI changes during pregnancy Outline a gastrointestinal change during pregnancy and why it occurs ## Footnote think GI tract and nutrients

Answer 37

- reduced motility of GI tract --> to increase absorption of vital nutrients

Question 38

# GI changes in pregnancy what 2 things can progesterone cause in pregnancy? ## Footnote think not being able to go number 2 and heartburn

Answer 38

- constipation - relaxed lower oesophageal sphincter (which can lead to heartburn)