L13: Fetal Growth

Question 1

What are the phases of foetal development?

Answer 1

Cellular hyperplasia - 4-20 wks (increase in foetal protein, weight + DNA)
Hyperplasia + concomitant hypertrophy (20-28 wks) - less increase in DNA
Hypertrophy - 28 wks - term, only increase in protein + weight

Question 2

What is the ponderal index?

Answer 2

Baby BMI

Question 3

What is the MAC/HC ratio?

Answer 3

Mid arm circum/head circum ration

Question 4

How many births does foetal growth restriction affect? (Both IUGR & SGA)

Answer 4

3-10%

Question 5

Consequences of foetal growth restriction

Answer 5

More likely to die in first yr of life + suffer from neonatal problems

Question 6

Basis of foetal programming

Answer 6

Plastic neuroendocrine system that can adapt to different nutrient states that continues throughout life

Question 7

What can foetal programming increase risk of?

Answer 7

Obesity, type 2 diabetes, BP, stroke, HF

Mostly secondary to changes in growth, metabolism + vasculature

Question 8

Mother born SGA are more likely to?

Answer 8

Have SGA babies w higher perinatal mortality

Question 9

Definite of perinatal mortality

Answer 9

Dying from 24 wks of pregnancy to 28 days of life

Question 10

What are the mechanisms of train generational effects of foetal programming

Answer 10

Epigenetics & inheritance of maternal mitochondria

Food restriction alters number + function of mitochondria

Question 11

What is macrosomia?

Answer 11

Birth weight > 4500g - clinical opposite to IUGR

Question 12

Causes of macrosomia

Answer 12

Greater gestational age, Male, maternal obesity, multiparity, maternal diabetes pre existing, erythroblastosis fetalis

Question 13

What is erythroblastosis fetalis?

Answer 13

Foetal has HF —> fluid build up causing macrosomia

Question 14

Pathophysiology of macrosomia

Answer 14

Increased maternal glucose —> increased foetal insulin —> increased IGF

Question 15

What regulates foetal growth?

Answer 15

Combination of substrate availability + endocrine/paracrine signalling (mainly IGF-1 + 2)

Question 16

What are the maternal factors affecting growth?

Answer 16

Ethnicity, BM1, Drugs esp cigarettes, alcohol, nutrition, maternal hypoxia, anaemia, chronic disease

Question 17

Why is maternal nutrition not that significant unless extreme under nutrition/placental insufficiency?

Answer 17

Placenta acts as moderator so any takes what it need from mother

Question 18

When in gestation does growth restriction occur?

Answer 18

Late gestation

Question 19

What are the foetal factors affecting growth?

Answer 19

Genetic factors e.g. Edwards, Patau’s, downs
Growth factors e.g. IGF, thyroxine
Congenital infection e.g. cytomegalovirus, toxoplasmosis, rubella

Question 20

What are the placental factors affecting growth?

Answer 20

Primary - errors in placentation+ EVT invasion in 1st trimester, often autoimmune
Secondary - hypertension, CKD, vasculitis, pro thrombotic disease, also due to twins sharing placenta

Question 21

How with IUGR change Doppler flow?

Answer 21

Diastolic notching - low flow in umbilical arteries during diastole
Raised RI

Question 22

What is the most common factor affecting foetal growth?

Answer 22

Placental factors

Question 23

What is symmetrical IUGR?

Answer 23

Overall small baby due to early growth insult e.g. virus, chromosomal abnormality
Disruption in cell hyperplasia stage if growth (4-20wks)

Question 24

When is doppler ultrasound done?

Answer 24

~ 6 + 20wks but only for high risk women

Question 25

What is asymmetrical IUGR?

Answer 25

Preserved growth of head as prioritising brain development | Decreased glycogen stores also decrease abdo circumference

Question 26

What can be used to assess fetal growth?

Answer 26

Symphsio fundal height | Ultrasound (look at head + abdo circumference)

Question 27

When is ultrasound scanning done in pregnancy?

Answer 27

12 wk - confirm due date, ch3ck developmental/genetic issues? 18-22 wks - know sex of baby + check for abnormalities

Question 28

What can be used to check foetal wellbeing short & long term?

Answer 28

Short - cardiotocograph (monitor fetal HR using transducer + uterine contractions), baby must be delivered immediately if there’s problem Long- Doppler ultrasound, if there’s a problem, MCA + ductus venous can also be checked if flow is affecting brain/heart

Question 29

What may growth restriction —> lower amniotic volume?

Answer 29

Blood diverted away from kidneys to brain so lower urine vol

Question 30

Why does gestational diabetes occur?

Answer 30

Pregnancy is a state of insulin resistance due to hormonal, inflammatory changes (e,g. Release of placenta growth hormone) Resistance increase with higher gestation

Question 31

What is the high risk group screened for GD?

Answer 31

Previous GD, history of insulin resistance, family history, PCOs, raised BMI, previous big baby, south Asian/black, Screen immediately if: significant glycosuria, macrosomia, polyhydaminos

Question 32

What are the maternal complications of gestational diabetes?

Answer 32

Pre eclampsia, pre term labour, instrumental delivery/c section, diabetes continues

Question 33

What are the foetal consequences of gestational diabetes?

Answer 33

Macrosomia —> shoulder dystocia Polyhydaminos Perinatal mortality due to hypoglycaemia after birth, jaundice, polycythaemia, hypocalcaemia

Question 34

Post natal management for gestational diabetes?

Answer 34

Slowly waning off insulin better Encourage breastfeeding Fasting glucose test done in 6 wks time/ HbA1C 3 months later to check if there’s still diabetes

Question 35

Management of GD during Pregnancy?

Answer 35

Diet restriction, metformin, insulin last - regular finger prick tests w strict glucose control, ultrasound done every 3-4 wks, foetal heart beat