Prevention and treatment of preterm labour Flashcards

1
Q

what is preterm labour

A

labour between 24 and 37 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what induces preterm labour

A

contractions or short cervix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what triggers early activation of normal labour process

A
  • placental/vascular problems
  • inflammation and infection
  • maternal stress
  • hormonal signals and uterine stretch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what category are the majority of preterm births

A

60% are spontaneous pre term births

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SPTB

A

spontaneous preterm births

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how common are medically induced preterm births

A

40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

rates of birth <30 weeks

A

less than 1% , but they account fo 80% of neonatal deaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is survival of PTB associated with

A

disability

  • cerebral palsy
  • severe sensory & cognitive impairment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

are there many causes of preterm labur

A

yes; a syndrom of multiple aetiologies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

causes of preterm labour

A
  • spontaneous pre term labour

- preterm premature membrane rupture which increases risk of infection and so labour is induced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

influecing factors of PTL

A
  • infection <32 weeks (40-80%)
  • cervical weakness / shortening
  • multiple foetus’
  • BV
  • maternal age
  • genetics
  • prenatal BMI & deit
  • environment
  • stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

impact of maternal stress on labour

A

increased cortisol stimulates activation stage earlier than normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

impact of placental haemorrhage on labour

A
  • thrombin directly activates the uterus

- contration associated proteins in the uterus are activated causing PTL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

effect of thrombin in PTL

A

directly activates the uterus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what do blood and thrombin do in PTL

A

induce uterine contractions through a COX-1 and COX-2 independent mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are uterine contractions induced independent of COX-1 and COX-2

A

by blood & thrombin

happens by placental haemorrhage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

impact of muliple foetuses on PTL

A

increased foetal hormone sectretion causing stimulation f activation stage earlie than normal (P and O)
earlier uterine stretch which induces COX-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Impact of infection and inflammation on PTL

A

inflammatory response comes before functional progesterone withdrawal instead of after and so becomes the driver of the system
- causes increase in COX-2 which drive activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

BV and PTL

A

evidence of sub clinical infection

  • cytokines raised in tissues from women with PTL
  • cytokines induce PG and MMPs
  • influx of immune cells in tissues from PTL women
20
Q

MMPs

A

matrix metalloproteinases, ripen cervix

21
Q

treatment aims of PTL

A
  • stop uterine contractions
  • revesal of cervix softening/ripening
  • prevential of inital PTL
22
Q

treatment approaches of PTL

A
  • smooth muscle relaxaction to inhibit contraction
  • treat infection
  • stop bleeding or response to bleeding
  • inhibit inflammation releated event (COX/PGR)
  • increase progesterone
23
Q

thrombin

A

clotting protein released in respose to bleeding e.g hemorrhage, but induces contractions

24
Q

what is a medication used to treat PTL

A

Tycolytics

25
tycolytics
use to treat PTL
26
are tycolytics effective
they do not improve the outcome of PTL but they give time for the baby to be given steroids to try and make foetal lungs develop as much as possible preterm for survival
27
retigabine
researched into treatment for PTL
28
what medication is being researched for treatment of PTL
retigabine
29
how does retigabine supposedly work
keeps K+ channels open which keeps smooth musle in relaxation state
30
what is retigabine
a Kv7 activator which keeps K+ channels open
31
what is the way forward for PTL
early prevention of PTL needing early identification | challenge is identifying who needs treatment
32
what is the challenge of treating PTL
knowing who needs treatment and when treatment is needed
33
what is prophylactic treatment
preventative
34
exampls of PTL prophylactic treatment strategies
1. treat infection 2. inhibit inflammatory events 3. prevent progesterone withdrawal 4. maintain active cAMP system
35
how can infection be prevented in PTL
prophylactic antibiotics
36
how can inflammatory events be prevented in PTL
COX-2 inhibitors, TLR anatagonists, PG receptor inhibitors
37
how can progesterone withdrawal events be prevented in PTL
synthetic or natural progesterone
38
how can active cAMP system be maintained to prevent PTL
inhibit PDE activity
39
why is COX-2 inhibitor thought to be good for treating PTL
- COX-2 increases in labour and PTL - COX 2 synthesise PGs - PGs cause contractions - COX-2 stimulates cytokins whch are high from inflammation in PTL
40
How would COX-2 inhibitor help PTL
with reduce the increased PGs, and cytokines from inflammation
41
example of COX2 inhibitor
rofecoxib
42
what is Rofecoxib
COX-2 inhibitor
43
results of Rofecoxib study
- mean gestation was 32 comapred to 34 for placebo - increased deliveries with R at <37 weeks - decrease birth weight in R - increase in premature rupture of memebrane in R
44
why is Rofecoxib not working
dont understand enough about the mechanisms and process/timing of PTL - could have affected the good PG pathways - may have been given at wrong stage - may be completely unrelated to PTL
45
rational for using progesterone to prevent PTL
- delays the effects of functional progesterone withdrawl - shown to prevent PTL in animals - thought to be anti-inflammatory - progesterone antagonists induce labour
46
why would you not want to use progesterone for PTL
levels are already high in pregenent women. May not be a good idea to add more
47
current study findings of progesteron use in PTL
- not associated with reduced risk of SPTB - no long term benefit or harm at 2 years of age study on going