1103 - Placentas and the stories they tell Flashcards
What is the placenta?
Interface between mother and baby, only interface baby has with ‘outside world’
Endocrine organ - sex hormones, HCG
Fulfils functions of liver, heart/lung, kidneys.
Essential for life and provides information about the health of the pregnancy.
How does the placenta form?
Following formation of the trophoblast, the outer syncytiotrophoblast develops projections into the endometrium, and the intermediate trophoblast also invades the endometrium, causing leakage into the syncytiotrophoblast’s lacunae. Eventually, the trophoblast envelops a network of arterial supply and venous drainage, allowing an interface (but not contamination) of foetal and maternal blood.
What are the three key hormones produced by the placenta? What do they do?
Progestins - support endometrium to provide a good environment for foetus, prevent uterine muscle contraction, inhibits LH and FSH, preventing ovulation during pregnancy.
Oestrogens - Stimulate growth of myometrium and development of mammary glands. Suppress gonadotrophin secretion from pituitary gland.
hCG - Binds to receptor on corpus luteum, preventing regression - the signal for maternal recognition of early pregnancy.
Why would you examine a placenta? Give 4 benefits.
Ultimately to provide answers to all concerned. Can tell you what went wrong and when.
1 - Clarification of pathophysiology of adverse outcomes.
2 - Improve management of subsequent pregnancies if possible.
3 - Understand antenatal/intrapartum events that have long-term neurological or developmental sequelae - early intervention.
4 - Independent assessment of factors that may contribute to poor outcomes - medico-legal.
Define the term infarction
The death of tissue that occurs when arterial blood supply is interrupted.
Define the term villitis
Inflammation of the chorionic villi. If chronic, no neutrophils, lymphocyte infiltrate with areas of perivillous fibrin deposition.
Define the term chorioamnionitis
Infection involving the chorion, amnion, and amniotic fluid - villi and decidua also usually involved.
