Flashcards in Lecture 14 - Fetal Growth and Nutrition Deck (25):
Stillbirth and growth?
around half of stillbirths have stunted growth, vast majority unidentified
Problems of large babies?
birth trauma, obesity, metabolic syndrome, interaction w maternal diabetes
mainly hyperplasia rather than hypertrophy
Hyperplasia of determinant and indeterminant tissue?
important determinant tissue hyperplasia stops during prenatal and early postnatal life e.g. nervous, muscle, pancreatic
Fetal growth restricition?
primarily placental cause, affects fat and lean tissue (maybe muscle), risk factor for stillbirth, neonatal death and asphyxia
Determiannts of birthweight centiles and problem of each?
population reference (preterm centiles too low), population standard (few preterm births), fetal growth curves (small sample), customised birthweights (ethnicity confounding)
time of organogenesis consistent growth supported directly by secretions from endometrial glands, chorionic villous regression and formation of discoid placenta
glucose (main, carbon source), amino acids (metabolic transport), lactate (oxidised), faty acid (membranes)
matches fetal growth to nutrition supply
main fetal IGF, drives growth
Actions of fetal insulin?
increase glucose uptake, fat deposition, protein anabolism; regulated by amino acids early, then placental glucose uptake
GH in fetus?
receptors in all tissues except liver, does not regulate IGF-1,
Cortisol and fetus?
fetal adrenal activation near term, turns on somatrophic axis inducing expression of growth hormone receptors in liver - promote cell differentiation, decrease DNA syntheis & cell division.
Enzyme that creates barrier to maternal cortisol?
11 BetaHSD2 (reduced in maternal protein malnutrition or ischemic placental disease -> preterm birth and/or slower growth)
Maternal constraint definition?
ability of the ureto-placental unit to supply oxygen & nutrients
Maternal constraint causes?
age, size, previous births, inter-pregnancy interval, macronutrient imbalance
Embryogenic factors leading to constraint?
twins, periconceptual malnutrition
best birthweight 80-90% for maternal and baby birth survival
Fetal growth defintion?
normally constrained by maternal environment, if endocrine status adequate growth is normally regulated by substrate supply
Postnatal growth definition?
normally to genetic potential, if nutritional status is adequate, gorwth is normally regulated by endocrine status
deficient trophoblast invasion into spiral arteries, leading to reduced S.A and fetal-placenta blood flow, also inflammation, hyper/hypoxia, thrombo-occlusive dmg
Overexpression of IGF-2 syndrome?
Beckwith Wiedemann Syndrome
Reduced expression of IGF-2 syndrome?
Russel Silver Syndrome
Postnatal health risks of FGR?
hypertension (low renal mass), ischemic heart disease (low lean mass), stroke (arterial stiffness), diabetes (insulin resistance), metabolic syndrome, osteoporosis.