Human labour & Delivery Flashcards
Define labour
Labour is increasing fundally dominated contractions combined with increasing cervical ripening and effacement
What are the stages of labour
- Cervical ripening and effacement increases
- Increased co-ordinated myometrial contractions
- Rupture of foetal membranes
- Delivery of infant (followed by delivery of placenta)
- Contraction of uterus
How long does labour last
12-48 hours
Baby is delivered in phase 2 and placenta is delivered in phase 3
What can initiate labour both during term and pre-term
During term - not sure - may be oestrogen:progesterone ratio, CRH or oxytocin
Pre-term - intrauterine infection, bleeding, multiple pregnancy, stress
What happens during cervical ripening and effacement
- Changes from rigid to flexible structure
- Remodelling - loss of ECM
- Recruitment of leucocytes such as neutrophils
- Inflammation mediated bu prostaglandin E2 amd IL-8
What happens to the myometrial contractions during labout
- A fundal dominance with increased power and coordination
- Mediators - Prostaglandin E2 increases, oxytocin receptors increase, contraction proteins
Describe what happens to the foetal membranes during labour
- Foetal membranes rupture as a result of a loss of strength due to change sin amnion BM
- Inflammation and leucocyte recruitment (exacerbated in preterm), increased MMPs
What hormonal changes happen to the cervix during labour
Increased prostaglandin E2, IL-8 and MMPs
What hormonal changes happen to the myometrium during labour
Increased prostaglandin E2 levels, oxytocin receptor upregulation, contraction associated proteins
what is NFkB
It is a proinflammatory transcription molecule related to IL-1B, IL-6, COX2, cPLA2 amd IL-8
What does NFkB exert its effects (mostly inflammatory) through
- COX-2
- IL-8
- IL-1B
- MMPs
- Oxytocin receptors
- PG receptors
- Contraction associated proteins
How is labour controlled
It is mostly under the control of platelet activating factor and corticotrophin releasing hormone
Where is CRH produced and what happens to it during labour
- Produced by the pituitary gland and the placenta
- Levels rise at the end of pregnancy, but CRH binding protein drop towards the end of pregnancy
- High CRH correlates with high COX-2 molecule expression
Where id platelet activating factor produced and how does it contribute to labour
- Part of the lung surfactant produced by maturing lungs
- Levels in amniotic fluid increase near term
- Therefore PAF levels are a sign of foetal maturity (may stimulate labour)
What is the parturition hypothesis
- PAF is directly made by the lungs which acts to create ILs which stimulate PG production
- CRH is made primarily by the placenta which stimulates the baby hypothalamus and then the adrenals to produce cortisol
