Lecture 14 - Fetal Growth and Nutrition

Question 1

Stillbirth and growth?

Answer 1

around half of stillbirths have stunted growth, vast majority unidentified

Question 2

Problems of large babies?

Answer 2

birth trauma, obesity, metabolic syndrome, interaction w maternal diabetes

Question 3

Fetal growth?

Answer 3

mainly hyperplasia rather than hypertrophy

Question 4

Hyperplasia of determinant and indeterminant tissue?

Answer 4

important determinant tissue hyperplasia stops during prenatal and early postnatal life e.g. nervous, muscle, pancreatic

Question 5

Fetal growth restricition?

Answer 5

primarily placental cause, affects fat and lean tissue (maybe muscle), risk factor for stillbirth, neonatal death and asphyxia

Question 6

Determiannts of birthweight centiles and problem of each?

Answer 6

population reference (preterm centiles too low), population standard (few preterm births), fetal growth curves (small sample), customised birthweights (ethnicity confounding)

Question 7

Histiotrophic nutrition?

Answer 7

time of organogenesis consistent growth supported directly by secretions from endometrial glands, chorionic villous regression and formation of discoid placenta

Question 8

Fetal diet?

Answer 8

glucose (main, carbon source), amino acids (metabolic transport), lactate (oxidised), faty acid (membranes)

Question 9

IGF-1?

Answer 9

matches fetal growth to nutrition supply

Question 10

IGF-2?

Answer 10

main fetal IGF, drives growth

Question 11

Actions of fetal insulin?

Answer 11

increase glucose uptake, fat deposition, protein anabolism; regulated by amino acids early, then placental glucose uptake

Question 12

GH in fetus?

Answer 12

receptors in all tissues except liver, does not regulate IGF-1,

Question 13

Cortisol and fetus?

Answer 13

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.

Question 14

Enzyme that creates barrier to maternal cortisol?

Answer 14

11 BetaHSD2 (reduced in maternal protein malnutrition or ischemic placental disease -> preterm birth and/or slower growth)

Question 15

Maternal constraint definition?

Answer 15

ability of the ureto-placental unit to supply oxygen & nutrients

Question 16

Maternal constraint causes?

Answer 16

age, size, previous births, inter-pregnancy interval, macronutrient imbalance

Question 17

Embryogenic factors leading to constraint?

Answer 17

twins, periconceptual malnutrition

Question 18

Normal constraint?

Answer 18

best birthweight 80-90% for maternal and baby birth survival

Question 19

Fetal growth defintion?

Answer 19

normally constrained by maternal environment, if endocrine status adequate growth is normally regulated by substrate supply

Question 20

Postnatal growth definition?

Answer 20

normally to genetic potential, if nutritional status is adequate, gorwth is normally regulated by endocrine status

Question 21

Placental insufficiency?

Answer 21

deficient trophoblast invasion into spiral arteries, leading to reduced S.A and fetal-placenta blood flow, also inflammation, hyper/hypoxia, thrombo-occlusive dmg

Question 22

Overexpression of IGF-2 syndrome?

Answer 22

Beckwith Wiedemann Syndrome

Question 23

Reduced expression of IGF-2 syndrome?

Answer 23

Russel Silver Syndrome

Question 24

Postnatal health risks of FGR?

Answer 24

hypertension (low renal mass), ischemic heart disease (low lean mass), stroke (arterial stiffness), diabetes (insulin resistance), metabolic syndrome, osteoporosis.

Question 25

Gestational diabetes?

Answer 25

glucose intolerance developing in pregnancy, excess fetal substrate (glucose) leads to increased insulin, the increased interaction leads to increased growth - risk of maternal typ II diabetes, and offspring diabetes and obesity