Abnormal placenta 29/09/2021

Question 1

Describe formation of the placenta?

Answer 1

• Initiated by trophoblast development
• Villous (non-migratory) trophoblast proliferate, differentiate forming chorionic villous trees. Vascular development occurs day 21 creating syncytiotrophoblast exchange surface.
• Extravillous (migratory) trophoblasts migrate from early conceptus and invade spiral arteries. Plug spiral arteries protecting embryo/placenta from high oxygen. Invade maternal spiral arteries converting to high capacity low compliance vessels.

Question 2

What is antiphospholipid syndrome?

Answer 2

-Increased blood clotting. Interrupts implantation and placental circulation.

Question 3

What is FGR?

Answer 3

Fetal growth restriction is also intrauterine growth restriction. Failure of the fetus to achieve genetic growth potential. Difficult to identify <50% spotted, no treatment available except delivery.

Question 4

What are the survivors of FGR at risk of?

Answer 4

• Neurodevelopmental disorders
• Negative effects on adult health coronary heart disease, hypertension and diabetes.
• Placental insufficiency causes 60% FGR.

Question 5

What’s pre-eclampsia?

Answer 5

-Syndrome characterised by new hypertension and proteinuria in second half of pregnancy which resolves postnatally.

Question 6

What’s the treatment of pre-eclampsia?

Answer 6

No effective treatment except delivery
• Early onset (< 34 weeks) pregnancy strongly
associated with FGR
– Significant cause of preterm birth
• Originates with abnormal development of placenta
• Patho-physiology not fully understood

Question 7

How do you detect placental insufficiency?

Answer 7

• Blood flow can be measured with a doppler ultrasound.
• Ultrasound beams are directed on moving red blood cells in a vessel. This movement changes during a cardiac cycle. Speeds up during systole, slows down at diastole and produced waveform .

Question 8

What does increased vascular resistance suggest?

Answer 8

-reduced blood flow

Question 9

What are the causes of abnormal placental blood flow?

Answer 9

-Abnormal villous structure in placenta. Failed branching angiogenesis. Predominance non-branching <25 weeks. Decreased VEGF/ Increased PIGF.

Question 10

What does the uterine artery doppler do?

Answer 10

-After 20 weeks reflects the adaptation of maternal circulation to pregnancy