Low birth weight and prematurity Flashcards

1
Q

What is the difference between small for gestational age (SGA) and intrauterine growth restriction (IUGR)?

A

Small for gestational age simply means that the baby is small for the dates, without stating why. The fetus may be constitutionally small, growing appropriately, and not at increased risk of complications

IUGR: when there is a small fetus (or a fetus that is not growing as expected) due to a pathology reducing the amount of nutrients and oxygen being delivered to the fetus through the placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is normal weight range of baby? [1]

What is LBW range? [1]
What is VLBW? [1]
What is Exremely Low? [1]

A

Low birth weight (LBW) = 2,499g or less regardless of gestational age

Sub-category very low birth weight (VLBW) = less than 1,500g

Sub-category extremely low birth weight (ELBW) less than 1,000g

Normal weight at term 2,500-4,200g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What defines a baby as having Intrauterine growth restriction (IUGR)? [3]

A

Fetus with birth weight less than 10th percentile of those born at same gestational age

Two standard deviations below population mean are considered growth restricted

IUGR should strictly refer to fetus that is small for gestational age and that displays other signs of chronic hypoxia or failure to thrive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 3 overiding factors that caues IUGR? [3]

A

Maternal factors (age / nutrition / stress / genotype / previous IUGR / HTN / substance abuse)

Placental and cord abnormalities (placental insuffiency - reduced AA transport, O2 delivery /; placental tumour / single umbilical artery / incorrect cord insertion)

Foetal factors (Congential heart disease / downs, turners, pataus syndrome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Normal fetal growth is characterised by cellular [] followed by [] and [] and finally [] alone

A

Normal fetal growth is characterised by cellular hyperplasia followed by hyperplasia and hypertrophy and finally hypertrophy alone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Growth rate of normal fetus: Weight gain is:
[] per day at 14-15 weeks of gestation
[] per day at 20 weeks
[] per day at 32-34 weeks
Then growth rate decrease

A

Weight gain
5g per day at 14-15 weeks of gestation
10g per day at 20 weeks
30-35g per day at 32-34 weeks
Then growth rate decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which maternal mesaurement (height) height approx increases at 1cm per week between 14 and 32 weeks? [1]

How does abdominal girth change after 30 weeks, per week? [1]

A

Symphysiofundal height increases approx 1cm per week between 14 and 32 weeks

BUT if have polyhydramnios then this would cause inaccurate readings

After 30 weeks - increases by 2.5 cm per week

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

After how many weeks does foetus growth rate decrease? [1]

A

at 32-34 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain the pathology behind Type 1 IUGR:

  • Is it caused by problem with mother or fetus? [1]
  • Is it symmetrical or asymmetrical? [1]
  • Between which weeks during pregnancy does it normally occur? [1]
A

Type 1 IUGR:

  • Problem with fetus growth during week 4-20 (when most of mitosis is occuring)
  • Everything is symmetrical / normal ration: but all parameters are below 10th percentile for gestational age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How would you detect infection in placenta histologically? [1]

A

Presence of lymphocytes or plasma cells

Mother should be transferring antibodies, not lymphocytes into the placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are causes of type 1 IUGR? [4]

A

Etiology:
* Genetic
* Infection (intrinsic to fetus)
* Multiple gestation
* Environmental toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
  • Explain pathophysiology of Type 2 IUGR [1] Which maternal pathologies is it associated with? [3]
  • When does in pregnancy does it usually occur? [1]
  • How do neonates appear? [1]
  • WHat do neonates have reduced growth in? [2]
A
  • Caused by uteroplacental insufficiency: uterus not providing enough nutrition for fetus. Associated with: maternal HTN / pre-eclampsia; renal disease; vasculapathies
  • Growth restriction begins after week 28 in stage of hypertrophy : Fetus has near normal cell number but size reduced
  • Asymmetry seen: head sized normal, but redistribution of fetal CO causes reduced abdomen and splachnic growth, whilst brain is spared.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mothers more at risk of giving birth to a IUGR baby have what wrong with them? [5]

A

Poor maternal nutrition: Low BMI at conception; Poor maternal weight gain during pregnancy

Pre-eclampsia

Renal disorders

Diseases causing vascular insufficiency

Infections (TORCH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of histocytes normally prevent vertical transmission of disease? [1]

A

Macrophages (histocytes) called Hofbauer cells prevent vertical transmission. Shouldn’t be found in choroinic villi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What complications of IUGR would you expect in antepartum period? [2]

A
  • Increased incidence of still births (52% of unexplained still births – die in utero)
  • Oligohydramnios (esp. type 2 - kidneys haven’t formed properly)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What pathology is 4-6 x higher of occuring in childhood because of IUGR? [1]

A

Cerebral palsy

17
Q

What complications of IUGR would you expect in intrapartum period? [2]

A

Higher incidence of meconium aspiration:: Fetal distress

Intrapartum fetal death

18
Q

What complications of IUGR would you expect in neonatal period? [5]

A
  • Increased incidence of hypoxic ischemic encephalopathy: heart not developed so o2 to brain is insufficient
  • Persistent fetal circulation insufficiency (patent ductus arteriosus - all O2 blood is mixed with deO2 - leads to hypoxia)
  • Difficulty in temperature regulation: Absent brown fat and small body mass to surface area in type 2
  • Poor glycogen stores may predispose to hypoglycemia
  • Chronic intrauterine hypoxia lead to polycythemia, necrotizing enterocolitis, other metabolic abnormalities
19
Q

What measurement would use clinically to diagnosis IUGR? [1]

What is normal growth of ^? [1]
What would indicate IUGR? [1]
What would indicate severe IGR? [1]

A

Symphysio-fundal height:

  • Lag in fundal height of 4 weeks suggestive of IUGR
  • Lag of >6 weeks is suggestive of severe IUGR
20
Q

Which mothers at more risk of givng birth of IUGR babies? [5]

A
  • Poor maternal nutrition (low BMI at conception; underweight / overweight)
  • Pre-eclampsia
  • Renal problem
  • Vascular insufficiency
  • TORCH infections
21
Q

Using a ultrasound to diagnose IUGR, what would you investigate? [3]

A

Head circumference
Abdominal circumference (AC) - AC highest sensitivity and greatest predictive value for diagnosis of IUGR
Amntiotic fluid volume

Can assess if type 1 or 2 by assessing differences in head vs abdomen

22
Q

Say you had identified IUGR using fundal-height. What investigation amay you do next to diagnose IUGR? [2]

A

Ultrasound [1]
Doppler ultrasound [1]

23
Q

Fundal height is a measure between which two points? [2]

A

Fundal height: Pubic symphysis to top of where can palpate uterus / fundus Exam Q!

24
Q

Type [] IUGR associated with oligohydramnios

A

Type 2 IUGR associated with oligohydramnios - due to reduced kindey function

25
Q

What is difference between pre-term and premature?

A

Pre-term: < 37 weeks

26
Q

Nutrition:

Ensuring that pregnant mother consumes which vitamin reduces the incidence of pre-term by 60%? [1]

A

Vitamin D level of mother of >40ng/ml reduces incidence of pre-term birth by 60%

Deficiency of 25(OH)D also increases morbidity and complications in preterm infants

27
Q

Explain the pathology that associated with lungs with pre-term birth? [5]

A

Respiratory distress syndrome

Hyaline membrane (fibrotic tissue) develops

Surfactant deficiency

Type II pneumonocytes

Results in decreased lung compliance, unstable alveoli

28
Q

What is intraventricular hemorrhage of new born?

A

Blood vessels in preterm may be more fragile and immature
Occurs within first 4 days

29
Q

For Type 1 & Type 2 IUGR, state if:

Cell number: Normal or Reduced? [2]
Cell size: Normal or Reduced? [2]

A

Type 1 IUGR:
* Cell number: reduced
* Cell size: normal

Type 2 IUGR:
* Cell number: normal
* Cell size: reduced

30
Q

Which type of IUGR does this baby display? [1]

A

asymmetrical IUGR

Note loss of fat whole over the body, visible rib cage, excessive skin fold whole over the body and relatively large heads compared with rest of the body.

31
Q

What are for maternal pathologies that can cause type 2 IUGR? [4]

A

Caused by uteroplacental insufficiency: uterus not providing enough nutrition for fetus. Associated with: maternal HTN / pre-eclampsia; renal disease; vasculapathies