Growth in Utero

What is the big problem with low birthweight

It indicates low kcal - there is a limited nutrient reserve

The baby is at risk of running out of nutrients

What is considered Intrauterine growth retardation (IUGR)

when the foetus is in the bottom 5th percentile of size

What could a baby be predisposed to if they have intrauterine growth retardation/small for gestational age

Predisposed to hypoglycemia, hypocalcemia, hypothermia, asphyxia, & cognitive dysfunction

Intrauterine growth retardation with rapid catch-up weight gain in early childhood could mean a baby is predisposed to what

Increased risk for adult-onset type 2 diabetes, hypertension, preeclampsia, dyslipidemia, and ischemic heart disease

What are large for gestational age (LGA) infants predisposed to

Predisposed to childhood weight gain, type 2 DM, metabolic syndrome

When a mother has gestational diabetes the foetus has a higher chance of what

Being LGA

Does rate of elongation of femur increase/decrease over time

Decrease

Does weight continue to increase throughout gestation period

Yes

What weeks make up the 3 stages of growth in pregnancy

Stage 1: 4-20 weeks

Stage 2: 20-28 weeks

Stage 3: 28-40 weeks

What type of cell growth occurs at each of the 3 stages

What is mainly being formed in stage 1

DNA content

What is the main growth happening in stage 2

Increasing cell size

What is the main growth happening in stage 3

Cell size rapidly increases

Rapid accumulation of fat, muscle & connective tissue

What is symmetric IUGR

Foetus is proportionally small
Head circumference (HC), Abdominal circumference (AC) and femur length (FL) are all in proportion

What fraction of IUGR cases is symmetric

1/3

Can symmetrical be diagnosed early

Yes

Possible causes of IUGR

Could be genetic, an infection or a karyotype anomaly

What is asymmetric IUGR

Head is much larger than the rest of the body.

The head is the size it should be but growth restriction applies to the rest of the body

The body is using its glucose/glycogen for growth & development for the brain and sacrifices the laying down of fat

Cause of Asymmetric IUGR

Nutritional

Which of Head circumference (HC), Abdominal circumference (AC) and femur length (FL) are normal or affected with asymmetric IUGR

Lower AC growth

Normal HC & FL

What causes the lower AC measurement

Liver shrinkage

Can asymmetric IUGR be diagnosed early

No - since it is caused by placental insufficiency, it is diagnosed in the late 2nd/3rd trimesters

Is a lack of IGF more likely to cause symmetric or asymmetric IUGR

Symmetric IUGR

What percentage of foetal growth is determined by genetics

30-70%

Give an example of genetics affecting foetal growth

Two-Fold Increased risk of IUGR in women who were SGA

SGA = small for gestational age

Give 2 examples of the physical environment affecting foetal growth

Placental Capacity
Nutrient Availability

Factors that affect foetal growth

How does hypervitaminosis come about

Some women overdose on vitamins with the best of intentions

What conclusions were made from growth hormone experimentation on mice

Growth hormone may not be essential for growth in utero

It is essential for growth once we are born

What conclusions were made from IGF-1 experimentation on mice

IGF-I is important for growth at all stages of
development (before and after birth).

What conclusions were made from IGF-2 experimentation on mice

GF-II is an important foetal growth factor, with unclear role in growth after birth

Are IGF-I and IGF-II regulated by GH during foetal development.

No

Is insulin important in foetal growth

Strong correlation with foetal growth

Does insulin have a strong/weak correlation with birth length

Weak

Does IGF-1 have a strong/weak correlation with birth length

Strong

Does IGF-2 have a strong/weak correlation with birth length

Weak

Does GH have a strong/weak correlation with birth length

No significant correlation

What causes Russell Silver syndrome

Loss of paternal expression of IGF-2

Russell Silver syndrome symptoms

Severe IUGR

What causes Beckwith Wiedemann syndrome

Overexpression of IGF-2

Beckwith Wiedemann syndrome symptoms

Foetal overgrowth

Regulation of foetal growth graph

Foetus hormone levels

Effect of high cortisol on birth length

Reduces IGF-1
Increases IGFBP-1
Inhibits linear growth

Effect of high cortisol on birth weight

Higher risk of IUGR

Effect of higher sex steroids on birth length

Birth length slightly greater in boys than girls (due to testosterone)

Effect of higher sex steroids on birth weight

Birth weight slightly greater in boys than girls (due to testosterone)

Role of thyroid hormone in foetal growth & development

Required for:

• Forming bones, brain & some somatic tissues

• General foetal increased size

• Foetal metabolism

• Controlling the bioavailability and effectiveness of
  other hormones and growth factors that influence foetal development (e.g. Catecholamines and insulin-like growth factors)

When is a pregnancy considered geriatric

37

How do you measure growth in utero?

On a scan:

• CRL = crown run length - line is drawn from crown to rear end (bum)

• Circumference of head

• BPD = Biparietal Diameter - diameter of skull

• Circumference of abdomen

• Femur length

Fundal test: From the base of the head (pubic symphysis) to the highest part of the uterus - measured on belly

This is compared with normal sizes for that GA (gestational age)

Why is a mother’s weight gain important

Mother's weight gain is measured to find out if there is enough nutritional availability for the foetus

If a woman's BMI was underweight, weight gain should be bigger

If a woman's BMI was overweight, weight gain should be smaller