Flashcards in Human labour + development Deck (24)
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1
Define miscarriage
Delivery at <23 weeks gestation
2
Define term labour
Delivery at 37-41 weeks gestation
3
Define pre-term labour
Delivery at 23-37 weeks gestation
4
Define labour
Increasing fundally dominated contractions combined with cervical ripening and effacement
5
What does labour involve?
- Cervical ripening & effacement (increasing)
- Coordinated myometrial contractions (increasing)
- Rupture of foetal membranes
- Infant delivery then placental delivery
- Uterine contraction
6
Generally how long are the 3 phases of labour and what happens in each?
Phase 1 - many hours - contractions, cervical changes
Phase 2 - hours - baby delivered
Phase 3 - 0.5 hours - placenta delivered
7
What initiates labour during term?
Not entirely sure
May be high oestrogen: progesterone ratio, CRH or oxytocin
8
What can initiate labour pre-term?
- Intrauterine infection
- Bleeding
- Multiple pregnancy
- Maternal stress
9
What changes does the cervix undergo during labour?
Ripening & effacement:
- Change from rigid -> flexible structure
- Remodelling - loss of ECM
- Recruitment (leucocytes e.g. neutrophils)
- Inflammation (prostaglandin E2, IL-8)
10
What happens to the myometrium during labour?
Co-ordinated myometrial contractions:
- Fundal dominance with increased power and coordination
- Mediators: increased prostaglandin F2a, increased oxytocin receptors, contraction proteins
11
What happens to the foetal membranes during labour?
Loss of strength due to changes in amnion BM -> rupture
- Inflammation and leucocyte recruitment (exacerbated in preterm), increased MMPS (matrix metalloproteins)
12
What is NFkB?
Pro-inflammatory transcription molecule
- Closely related to IL1b, IL6, COX2, cPLA2, IL8
13
What does NFkB inititiate effects through?
COX2, IL8, MMPs, oxytocin receptors, PG receptors, contraction-associated proteins
14
What must be constitutively expressed before any changes conducive to labour can be seen?
PGE2
15
What factors control labour?
CRH & PAF -> activate other molecules and ultimately MMPs, PGE2 and upregulation of oxytocin receptors
16
What produces CRH?
Pituitary gland AND placenta
17
How do levels of CRH and CRH-binding proteins change towards the end of pregnancy?
CRH level: increase
CRH-binding protein: decrease
18
What is the relationship between CRH and COX2 expression?
High CRH correlates with high COX2 expression
19
What is PAF?
Part of lung surfactant that is produced by maturing lungs before birth
20
How do levels of surfactant and therefore PAF change as the foetus nears term?
Surfactant: increases
PAF: increases
21
What do CRH and PAF upregulate?
- PGE2 and COX2 expression
- IL1b levels
22
What are the three theories for labour induction?
- Anything that increases CRH may -> labour (stress, multiple infants)
- Anything that increases muscle contraction may -> labour (excess uterine stretch)
- Anything that activates inflammatory cascades may -> labour
23
How do progesterone levels change during pregnancy?
-Needed to sustain pregnancy (PR blockade = pregnancy loss)
-Remain high until after delivery of placenta so PR receptor must be disrupted
24
