Labour Flashcards
How many weeks of gestation is defined as “term”?
37-41
Recall the boundaries of “pre-term” and “very pre-term” delivery
22-37 weeks
Recall the factors moderating the cervical changes that occur in labour
PGE2
IL8
MMPs
Recall the factors moderating the endometrial changes that occur in labour
PGE2
Oxytocin receptor upregulation
Where is PGE2 produced in labour?
Foetal membranes
Describe the changes in the foetal membranes during labour?
Inflammatory process occur, and the FMs secrete PGs, ILs and MMPs
Summarise the endocrine biochemical processes of labour induction
CRH and PAF upregulate pro-inflammatory cytokines
Progesterone loses its anti-labour effects at term
Summarise how progesterone loses its anti-labour effects at term
There is a negative interaction between NFKB and the PR
What is the role of NFKB in labour?
Involved in pro-inflammatory processes, upregulates cytokines and oxytocin + PG receptors
Describe the epithelial changes in the foetal membranes during labout
Amnion epithelium on BM loses strength
What 2 processes are undergone by the cervix in labour?
Effacement and dilatation
What is cervical effacement?
Cervix becoming softer, thinner and more flexible
What must happen in order for cervical effacement to occur?
Excessive ECM remodelling
Recall the key mediators in uterine contraction in labour
PGE2 from foetal membranes
Oxytocin receptor
How long does the onset of uterine contraction last in labour?
About 8 hours
When do foetal membranes usually rupture?
During onset of labour
What is the 2nd stage of uterine contraction, and how long does it last?
Expulsive effort
About 30 mins
Name the 3 stages of labour
- Cervical ripening and effacement and onset of myometrial contraction
- Delivery of infant
- Delivery of placenta
How long should the 3rd stage of labour last?
30 minutes
Summarise the non-haematological events of the 3rd stage of labour
Uterus contracts very powerfully to expel the placenta, causing a rupture between the uterus service and the placenta –> delivery
What conditions are required in the spiral arteries in order to achieve successful haemostasis in placental delivery
High flow and low pressure
How does the myometrium control haemostasis following placental delivery?
Contracts forecefully
What is involution and what drives it?
The powerful myometrial contraction that causes haemostasis of spiral arteries
Driven by oxytocin (contractile hormone)
Summarise the hypothesis for parturition
CRH increase
Foetal adrenal stimulated
Positive feedback in lacenta between CRH and cortisol
Cortisol drives IL, PG and PAF production = pro-labour factors