Foetal growth and nutrition Flashcards
Consequences of poor foetal growth?
…
Consequences of large babies?
…
Term defention
37 wks
Full term defenition
39wks - babies born with lowest risk of health issues (Cerebral Palsy/ respiratory distress syndrome) at full term
Appropriate weight for gestation
10th-90th percentile. Anything below or above is considered low growth or overweight.
Main process of foetal growth?
Hyperplasia (inc. cell size)»_space; Hypertrophy
What is our Metabolic capacity determined by?
Metabolic capacity is determined by foetal growth as all our important organs such as kidney/heart/skeletal muscle do their growing early on in gestation.
Embryonic nutrition
Histiotrophic: Uterine glands secrete carbs into intervillous space.
Foetal nutrition and foetal supply line
Haemotrophic
What is the biggest general cause of foetal growth restriction?
Placental
Foetal diet substrates, mode of transport, and role.
Glucose - Facilitated diffusion - main energy source, foetal growth (carbon)
Amino acids- Active transport - Balance between oxidation (creating energy) and growth of placenta.
Lactate - Produced by placenta - Energy (oxidation)
Fatty acids- Readily diffuse - Cell membranes and energy source (adipose tissue)
Determinants of foetal growth
- Nutrition
- Hormones
- Genetics
Main foetal hormones, where they are produced and their roles.
IGF-2 and IGF-1
What regulates IGF-1 levels
Foetal nutrition, if maternal starvation, then dec. in IGF-1 levels. Vice versa
What regulates IGF-1 levels
Foetal nutrition, if maternal starvation, then dec. in IGF-1 levels. Vice versa
AND
Insulin
Actions of insulin in foetus.
Tissue accretion (protein disposition) and fuel storage (cell uptake of glucose)
Growth hormone
High concentrations
Low effect on weight
Effects length/height
Does not regulate IGF-1
Role of glucocorticoids
Determines timing of labor
Tissue maturation
Maternal barrier to cortisol
Enzyme that breaks down maternal cortisol
If enzyme is deficient/damaged (protein malnutrition or ischaemic placental disease) then cortisol passes through placenta and induces preterm birth. Acts a s a protective mechanism, but causes growth defects.
General genetic influences on foetal growth
Not much, race and sex <20% of variance
Determines lean muscle mass
Mostly determined by constrain to uterus (non genetic and non-pathological.)
Maternal constraints of foetal growth
Maternal weight
Maternal height
Maternal nutrition.
Constraints of embryogenesis
Main one is twins (less foetal growth with twins)
Periconceptual nutrition
Causes of foetal undernutrition
Idiopathic
Vascular disease (no transformed spiral a.?)
Sever maternal undernutrition
Genetic disorders affecting foetal growth
Beckwith Wiedmann’s syndrome: Overexpression of IGF-2 from PATERNAL mutation causing large tongue, hemi-hypertrophy .
Russell Silver syndrome: IGF-2 deficiency from maternal allele mutation. Causing SGA, small heigh, normal head size.
Gestational diabetes
…
