Fetal Growth

Question 1

Define fetal growth

Answer 1

The increase in mass that occurs between the end of the embryonic period and birth

Question 2

What parameters are used to estimate fetal weight?

Answer 2

Biparietal diameter (BPD), Head circumference (HC), abdominal circumference (AC), Femur length (FL).

Question 3

Why are USS used in pregnancy?

Answer 3

Main role is to assess the wellbeing of the fetus. Assessing growth trends. Predicting the need for premature delivery. Date a pregnancy

Question 4

What other method can be used to assess fetal growth? (other than USS)

Answer 4

Symphysis fundal height. ( palpate abdomen to find the pubic symphysis and top of the uterus).

Question 5

Name 3 factors that can mean an inaccurate EWF using symphysis fundal height.

Answer 5

Underestimation- wrong date of last period, Small for gestational age, oligohydramines, baby lying horizontally.

overestimation- wrong date for last period, multiple preganacies, large gestational age, polyhydramines, high BMI mother, fibroids.

Question 6

Define SGA

Answer 6

Birth weight <10th centile

Question 7

What maternal factors influence foetal growth?

Answer 7

Economic status. Age (<16 and >35), Abnormal BMI, smoking, alcohol, diet, anaemia, hypertension, depression, illness/chronic disease, drugs and toxins.

Question 8

In general is the first or second child larger?

Answer 8

The second child.

Question 9

What cellular changes normally occur during the course of gestation?

Answer 9

Week 4-20= hyperplasia
week 20-28= hyperplasia and hypertrophy
week 28-40= hypertrophy dominates

Question 10

What fetal hormones are involved in regulating fetal growth and development?

Answer 10

Cortisol, Thyroxine, insulin and pituitary growth hormone

Question 11

What hormones are responsible for tissue differentiation?

Answer 11

Cortisol and thyroxine (is also responsible for accretion, which is the increasin in number of layers of cells)

Question 12

Define IGUR

Answer 12

Failure of an infant to achieve its predeterimed genetic potential for a variety of reasons.

Question 13

Why does IGUR usually develope in the 2nd and 3rd trimesters?

Answer 13

As this is when the majority of fetal growth occurs and influencing factors have the biggest impact.

Question 14

what is the role of fetal insulin?

Answer 14

Modifies IGF expression IGF1–> IGF2, increases mitotic drive and increases tissue availabilty for accretion

Question 15

Name 2 fetal factors impacting fetal growth

Answer 15

Multiple preganacies, structural abnormalities, genotype, gender and chromosomal abnormalities.

Question 16

Name 4 placental factors that can cause IUGR

Answer 16

Impaired trophoblast invasion, partial abruption/ infarction, chorioamnionitis, placental cyst, placental praevia

Question 17

What usually causes preeclampsia and why is it associated with IUGR?

Answer 17

Deminished remodelling of spiral arteries in the uterus, causing decreased placental blood flow. This decreases the nutrients reaching the baby and restricting growth.

Question 18

Preeclampsia is difficult to treat but what can be done to limit the damage?

Answer 18

Give corticosteriods to baby at birth and balance between early delivery risk and benefits.

Question 19

When are at risk patients screen for IUGR?

Answer 19

at 24 weeks

Question 20

Which centiles are most sensitive and most specific for IUGR/FGR

Answer 20

10th is most sensitive (everyone but some false positives)

3rd is most specific (potentially some false negatives)

Question 21

What is the difference between fetal age and gestational age?

Answer 21

Gestational age is measure from the first day of the mothers last period.
Foetal age is from fertilisation so is usually two weeks less than GA.

Question 22

What are the parameters to define preeclampsia?

Answer 22

Bp raised aboved 140/90 on 2 spearate occasions .4hrs apart.
proteinuria > 0.3g/day after 20 weeks
oedema

Question 23

Define low birth weight and very low birth weight

Answer 23

LBW= <2500g

VLBW=<1500g

Question 24

What are the short term risks associated with FGR?

Answer 24

Respiratory disress
Intraventricular bleed
Sepsis
hypoglycaemia
necroenterocolitis
jaundice
Electrolyte imbalances

Question 25

What tests are done to determine IUGR?

Answer 25

PAPPA <0.3MOM

Uterine atery doppler scan 60-70% loss of function gives abnormal reading

Question 26

which week and baby weight would you aim to deliver a FGR baby after?

Answer 26

> 28 weeks and >500g