Placentation 2

Question 1

Define intra-uterine growth retardation

Answer 1

Impaired growth and development of the mammalian embryo/foetus or its organs during pregnancy

• Can be naturally occurring or environmentally induced
• Is basically failure of foetus to acheive its growth potential

Question 2

List factors causing IUGR

Answer 2

• Maternal nutrition and/imbalance
• Maternal intestinal malabsorption
• Ingestion of toxic substances
• Environmental temperature and stress
• Disturbances in maternal or foetal metabolic and homeostatic mechanisms
• Insufficiency or dysfunction of the uterus endometrium or placenta
• Poor management

Question 3

What may impair placental efficiency?

Answer 3

• Placental size/weight
• Uteroplacental blood flow
• Surface area:placenta with maternal endometrium
• Presence of multipe foetuses

Question 4

Explain the effect of multiple foetuses on IUGR

Answer 4

• Need to share resources
• Reduces foetal growth and birth weight
• Reduced capacity for nutrient exchange (esp in horses)

Question 5

Explain the role of gynaecological immaturity on IUGR

Answer 5

• Breeding at immature body weight
• Mother and foetus compete for nutrients
• High nutrition intake leads to smaller offpsring if immature as competition is increased

Question 6

Describe the human maternal-foetal interface

Answer 6

• Villus in contact with lining of uterus
• Trophoblast cells invade linig of uterus in clusters
• Also invade up spiral arteris
• Embed in wall, destroy musclar tissue
• Becomes distended tube supplying foetus with as much blood as needed

Question 7

Describe the process of pre-eclampsia in humans

Answer 7

• In late pregnancy, artery converted to large sinus
• In PE, cytotrophoblast cells do not invade enough or far up enough artery
• Do not get formation of distended tube
• Not enough blood to foetus, increased blood pressure and heart rate in mother to compensate

Question 8

What is the role of the human maternal-foetal interface in disorders of palcental growth?

Answer 8

• Can cause a variety of conditions if occuring too much or too litte
• Too much invasion: placenta accreta
• Too little: pre-eclampsia
• Far too little: miscarriage