Physiology of Pregnancy

Question 1

What is the role of the placenta?

Answer 1

To produce hormones in order to maintain pregnancy.

The driving force behind maternal adaptations.

Question 2

What is the role of HCG?

Answer 2

Signals the corpus luteum to continue secreting progesterone.

Question 3

What is the role of placental villi?

Answer 3

Project into the uterine wall, providing anchorage and increasing contact between the uterus and the placenta, allowing for a greater rate of nutrient/waste exchange.

Question 4

What plays the role of the foetal lungs?

Answer 4

The placenta.

Question 5

What factors facilitate the supply of foetal oxygen?

Answer 5

Foetal haemoglobin (increased O2 capacity)
Increased haemoglobin in foetal blood
Bohr effect

Question 6

How does the Bohr effect impact foetal oxygenation?

Answer 6

Hb can carry more O2 due to a low PCO2.

Question 7

How do electrolytes cross the placenta?

Answer 7

With water during osmosis.

Question 8

Name 2 drugs to avoid in pregnancy due to their teratogenicity?

Answer 8

Carbamazepine

Tetracyclines

Question 9

What is the role of human placental lactogen (HPL)?

Answer 9

A growth hormone, causing increased formation of protein tissue.

Reduces insulin sensitivity of mother - allowing energy to reach the foetus.

Question 10

At around which week does HPL begin to be produced?

Answer 10

Week 5.

Question 11

What is the role of progesterone in pregnancy?

Answer 11

Decreases uterine contractility

Enlarges breasts for lactation

Question 12

What is the the role of oestrogen in pregnancy?

Answer 12

Enlarges uterus
Enlarges breasts
Relaxation of ligaments

Question 13

How often should HCG levels double in early pregnancy?

Answer 13

Every 48 hours.

Question 14

What symptoms are associated with increasing levels of HCG?

Answer 14

Nausea and vomiting

Question 15

What does a slow rising/static HCG level indicate?

Answer 15

Ectopic pregnancy

Question 16

What does a falling HCG level indicate?

Answer 16

Miscarriage or an unviable pregnancy.

Question 17

What do extremely high levels of HCG suggest?

Answer 17

Multiple pregnancy

Molar pregnancy

Question 18

At which gestation does HCG levels begin to fall again?

Answer 18

12-14 weeks.

Question 19

What change is seen in cardiac output during pregnancy?

Answer 19

Increase by 30-50%.

Question 20

What change is seen to BP in pregnancy?

Answer 20

Drops in 2nd trimester by around 15mmHg, with a rise in the 3rd trimester expected.

Question 21

What is anaemia defined as in the first trimester?

Answer 21

<110g/L of Hb

Question 22

What is anaemia defined as in the second and third trimesters?

Answer 22

<105g/L of Hb

Question 23

What is a normal haemoglobin level in a healthy individual?

Answer 23

120-160g/L of Hb

Question 24

Why do Hb levels drop in pregnancy?

Answer 24

Increased plasma volume.

Question 25

What respiratory changes are seen in pregnancy?

Answer 25

Increased respiratory rate Increased tidal and minute volume Slight decrease in PCO2

Question 26

Are vital capacity and PO2 changed by pregnancy?

Answer 26

No

Question 27

Are GFR and plasma affected by pregnancy?

Answer 27

Yes, they increase by 30-50%.

Question 28

Why does urinary frequency increase during pregnancy?

Answer 28

Increased uterine pressure | Increased urinary formation (minimal)

Question 29

Is pregnancy a hypercoagulable state?

Answer 29

Yes This is advantageous in preventing haemorrhage, however there is increased risk of thromboembolism.

Question 30

What supplementation is advised in pregnancy?

Answer 30

``` Folic acid Vitamin D High protein diet High energy intake Iron supplements (if needed) Vitamin B ```

Question 31

What rises to increase uterine excitability towards the end of pregnancy?

Answer 31

Oestrogen : Progesterone ratio The greater the amount of oestrogen present, the greater the rate of uterine contraction.

Question 32

What is the role of oxytocin?

Answer 32

Increase contractions and uterine excitability.

Question 33

Where is oxytocin produced?

Answer 33

The posterior pituitary of the mother.

Question 34

What are Braxton-Hicks contractions?

Answer 34

Tightenings of the uterus felt towards the end of pregnancy. These are not labour.

Question 35

Are Braxton-Hicks contractions regular and painful?

Answer 35

No, they are neither of these things.

Question 36

What is the first stage of labour?

Answer 36

Dilatation of the cervix (can take 8-24 hours).

Question 37

What is the second stage of labour?

Answer 37

Passage of the foetus through the birth canal (can take a few hours).

Question 38

What is the third stage of labour?

Answer 38

Expulsion of the placenta.

Question 39

What role does oestrogen play in breast development?

Answer 39

Maturation and growth of the ductile system of the breasts, allowing for milk production.

Question 40

What role does progesterone play in breast development?

Answer 40

Allows for development of the lobule-alveolar system.

Question 41

Which hormone stimulates milk production?

Answer 41

Prolactin

Question 42

What is the antibody-rich milk produced in the first few days following birth called?

Answer 42

Colostrum