Fetal physiology

Question 0

How often are breathing movements in the last trimester?

Answer 0

1-4 hours

Question 1

By the 8th week, what is developed in terms of lung tissue?

Answer 1

The bronchial tree

Question 2

What is the function of breathing movements in the neonate?

Answer 2

To bring amniotic fluid in
For mechanical
For washing out the lungs

Question 3

When do fetal lungs start to produce surfacant?

Answer 3

20-30 weeks

more after 30 weeks

Question 4

What happens if there is a lack of surfacant in the neonate, which is a common problem in premature babies?

Answer 4

respiratory distress syndrome

Question 5

What do you need to give the mother if the baby is going to be born premature and why?

Answer 5

steroids to encourage surfacant production

Question 6

Why does amniotic fluid surround the fetus?

Answer 6

Mechanical protection
To allow the baby to keep in its fluids - else it would just diffuse out
Nutrients
Moist environment

Question 7

At the start of pregnancy, up until week 8 what produces amniotic fluid?

Answer 7

The mother and it diffuses across the placenta

Question 8

In the fetal period of pregnancy, what produces amniotic fluid?

Answer 8

The fetus, it swallows it, puts it through the gut and then is excreted via the kidneys, and the process starts again

Question 9

How much amniotic fluid is produced at:
week 8
week 38
week 42

Answer 9

10ml
1 litre
300 ml

Question 10

What is the remnants of amniotic fluid in the gut called?

Answer 10

Meconium

Question 11

What is amniocentesis?

Answer 11

The using of amniotic fluid to assess fetal wellbeing
cytological and biochemical studies
neural tube defects and chromosomal abnormalities

Question 12

What is bilirubin?

Answer 12

Breakdown of rbc

Question 13

Why can a fetus not conjugate billirubin?

Answer 13

Because the liver is not functioning properly

Question 14

If the fetus turns Jaundice when they are born, what can you do to encourage conjugation of bilirubin?

Answer 14

expose the baby to light

Question 15

What is polyhydraminos?

Answer 15

This is too much amniotic fluid

Due to oesophogeal or duodenal atresia and can lead to CNS abnormalities

Question 16

What is oligohydraminos?

Answer 16

This is too little amniotic fluid
Due to poor or absent kidney function
Due to small placenta

Question 17

What can oligohydraminos cause?

Answer 17

pre-eclampsia

Question 18

What is pre-eclampsia?

Answer 18

Hypertension and protein in the urine

Question 19

What is eclampsia?

Answer 19

Seizures

Question 20

How do you treat eclampsia?

Answer 20

See out the fit, so put patient on their side, relax them and give magnesium
Then birth

Question 21

Where does the fetus get its glucose?

Answer 21

From the mother via facilitated diffusion

Question 22

What can you measure to see that the fetus is storing glycogen correctly?

Answer 22

abdominal circumference which gives you an estimation of the liver

Question 23

When do fetal movements occur?

Answer 23

8 weeks

but not felt until about the 15-17th week by the mother

Question 24

When does myelination complete?

Answer 24

Not until after birth

Question 25

How much o2 storage does the fetus have?

Answer 25

2 minutes - can become a problem in labour

Question 26

What does progesterone do to the body in terms of smooth muscle?

Answer 26

Relaxes it

Question 27

What does progesterone encourage the fetal endocrine system to produce?

Answer 27

Corticosteroids - such as thyroid hormones which are neccessary for growth, nervous system and the cardiovascular system

Question 28

When is the fetal endocrine system active from?

Answer 28

Week 12

Question 29

What is a good indication that the fetus is ready to birth?

Answer 29

Regular bodily rhythms such as heart rate and breathing

Question 30

What is fetal heart rate?

Answer 30

160-180bpm

Question 31

What causes the neonate to take its first breath?

Answer 31

Trauma and cold air

Question 32

What does the first breath of neonate cause?

Answer 32

Decreased pulmonary resistance and an increase in arterial pressure which closes the foramen ovale

Question 33

What closes the ductus arteriosus?

Answer 33

Smooth muscle in the wall is sensitive to high pO2 which closes it - contracts

Question 34

What happens to the ductus venosus?

Answer 34

It stays open for several days after birth closes within 2-3 months but there is a spinchter which contracts and directs blood flow through the liver

Question 35

What happens to fetal CO2?

Answer 35

Fetus cannot get rid of it, so it diffuses into mothers circulation Mother then has a degree of hyperventillation which causes respiratory alkalosis

Question 36

Why can the fetus not excrete CO2?

Answer 36

acid base problems | not a functioning kidney in terms of this respect

Question 37

What is the function of the ductus venosus?

Answer 37

To shunt blood around the liver

Question 38

What is the function of the ductus arteriosus?

Answer 38

To shunt blood from the pulmonary artery to the aorta

Question 39

What is the function of the foramen ovale

Answer 39

To shunt blood from the right atrium to the left atrium

Question 40

What is the fetal O2 saturation?

Answer 40

60%

Question 41

What is fetal O2 kPa?

Answer 41

4

Question 42

Explain the fetal circulation of blood

Answer 42

Blood arrives at umbilican vein, shunts around liver, into ivc, into right atria -> FO -> LA -> LV -> aorta -> carotids and brain -> RA -> RV -> PT -> aorta -> back around the body to the umbilical arteries where it picks up O2 again

Question 43

What are the stages of pregnancy in terms of the fetus?

Answer 43

Pre-embryonic - 1-2 weeks Embryonic - 3-8 weeks Fetal - 9-40 weeks

Question 44

What happens in the embryonic period?

Answer 44

Growth of all systems They just need to mature Placental growth

Question 45

What growth deposition is in early fetal period?

Answer 45

Protein deposition

Question 46

What growth deposition is in the late fetal?

Answer 46

Adipose deposition

Question 47

How can you measure fetal growth?

Answer 47

Symphysis - fundal height Crown - rump length Abdominal circumference and femur length Biparietal diameter

Question 48

What is good about the symphysis - fundal height?

Answer 48

That it is not invasive | It is proportional to the number of weeks the fetus is

Question 49

What lag in growth is indicative of a growth restriction?

Answer 49

Over 4cm - lie of fetus - amniotic fluid - number of fetus - extent of engorgement of head

Question 50

When is CRL measured?

Answer 50

between weeks 7-12

Question 51

Why is US done at 20 weeks - known as the anomalies scan?

Answer 51

``` Predicts anomalies Growth of fetus Number of fetus Gender of fetus All systems are developed ```

Question 52

What does abdominal circumference measure?

Answer 52

Growth of the liver | Glycogen storage

Question 53

Why is anatomy ideal for fetal investigation?

Answer 53

Its safe, non invasive, doesnt affect brain growth

Question 54

Why might a transvaginal US be performed on someone who has miscarried a lot?

Answer 54

Because it ensures baby has implanted in the correct place and that its developing well during the embryonic and early fetal period

Question 55

``` What is: the average the growth restricted and the macrosomic birth weight? ```

Answer 55

3500g 2500g 4500g

Question 56

Why might a baby be macrosomic?

Answer 56

Gestational diabetes

Question 57

Why might a fetus be too light?

Answer 57

Premature Small mother Growth restriction

Question 58

What are the 4 stages of lung development?

Answer 58

Pseudoglandular Canalicular Terminal sac Alveolar

Question 59

What happens in the pseudoglandular stage and when is it?

Answer 59

Differentiation into terminal bronchioles | 8-16

Question 60

What happens in the canalicular stage and when is it?

Answer 60

Respiratory bronchioles | 16-26

Question 61

What happens in the terminal sac stage and when is it?

Answer 61

``` Development of terminal sacs Some primitive alveoli Alveolar type II pneumocytes Surfacant 27- term ```

Question 62

What happens in the alveolar stage and when is it?

Answer 62

Alveolar develop | From birth until 8 years of agee

Question 63

What happens to the amniotic fluid that is in the lungs after birth?

Answer 63

Expelled at birth and reabsorpbed

Question 64

When are the lungs viable from?

Answer 64

Week 24 onwards due to some production of surfacant

Question 65

When is the heart rate felt by a stethescope?

Answer 65

About 16-18 weeks

Question 66

When can fetal heart rate be felt with a doppler stethescope?

Answer 66

10 weeks

Question 67

When does fetal kidney function begin?

Answer 67

week 10

Question 68

When does myelination of the brain begin?

Answer 68

In the 9th month

Question 69

What senses work first?

Answer 69

Hearing and taste | Retina is immature at birth and the eyelids are fused until the 9th month

Question 70

What is an asymmetrical restriction?

Answer 70

Where the abdominal growth lags behind and there is relative sparing of head growth Occurs in the last part of pregnancy

Question 71

What is symmetrical growth restriction?

Answer 71

This is where the restriction affects the head as well as the body

Question 72

What clinical tests can you use for growth and development?

Answer 72

``` US Doppler non stress test biophysical profiles vibroacoustic stimulation contraction stress test fetal movements kick chart ```

Question 73

what is a non stress test?

Answer 73

Monitor fetals heart rate with changes in fetal movement