stages of labour Flashcards

1
Q

progesterones influence on labour

A

keeps uterus settled
prevents formation of gap junctions
HINDERs contractility of myocytes

progesteron -> P -> prevents

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2
Q

oestrogens influence on labour

A

makes uterus contract
promotes prostaglandin production

oestrogens -> O -> opens

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3
Q

oxytocins influence on labour (+pathophysio ish)

A

initiates + sustains contractions

acts on decidual cells to promote prostaglandin release
- systhesised directly in decidual + extraembryonic fetal tissues + placenta

number of oxytocin receptors increases in myometrial + decidual cells near end of pregnancy

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4
Q

cervical softening in labour

A

increase in hyaluronic acid gives increase molecules among collagen fibres

-> decrease in bridging among collagen fibres decreases in firmness of cervix

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5
Q

signs of labour

A

a show = shedding of mucus plug from cervix
rupture of membranes
regular, painful contractions
dilating cervix on examination

latent 1st stage = painful regular contractions, changes to cervix, dilation up to 4cm

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6
Q

induction of labour

A

where labour is started artificially - happens in around 20% of pregnancies

guided by Bishops score

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7
Q

indication of induction of labour

A
  • prolonged pregnancy - 1-2wks after the estimated date of delivery
  • prelabour premature rupture of membranes, where labour does not start
  • intrauterine death

maternal medical problems
- diabetic mother >38wks
- pre-eclampsia
- obstetric cholestasis

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8
Q

Bishops score

A

best + safest method to determine if safe to induce labour
- <=4 -> indicates unfavourable cervical ripening, UNLIKELY to start without induction
- >=9 -> cervix ripe/favourable, high chance of spontaneous labour

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9
Q

what is factors are used to create bishops score

A

dilation
effacement
station
cervical consistenct
cervi position

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10
Q

methods of induction of labour

A

membrane sweep - finger passed through cervix to rotate against uterin wall, separating chorionic membrane from decidua

vaginal prostaglandins E2 (NOT oral)
misoprostolol
oxytocin infusion
amniotomy

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11
Q

induction of labour method with bishops score >/< 6

A

<=6 = vaginal prostaglandins or oral misoprostol

> 6 = amniotomy + IV oxytocin

(>=9 indicates cervix is ripe/favourable = high chance of spontaneous labour)

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12
Q

complications of induction of labour

A

uterine hyperstimulation - prolonged + frequent uterin contractions

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13
Q

preterm labour rupture of membranes (PRROM) confirmation

A

(occurs in 2% of pregnancies but assoc with 40% of preterm deliveries)

confirming PPROM
- speculum exam to look for pooling of amniotic fluid in posterior vaginal vault
avoid digital exam due to risk of infection

  • use may also show olihohydramnios
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14
Q

management of preterm labour rupture of membranes (PRROM)

A

admit
monitor chorioamnionitis is not developing
oral erythromycin should be given for 10days
antenatal steroids
delivery should be considered at 34wks
- balance risk of maternal chorioamnionitis + risk of resp distress syndrome in neonate

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15
Q

when does delivery of baby normally occur + what are the stages of labour

A

labour + delivery normally occur 37 -42wks gestation

1st stage = from onset of labour (true contractions) until 10cm cervical dilation
2nd = from 10cm cervical dilation until delivery of baby
3rd = from delivery of baby until delivery of placenta

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16
Q

stages of first stage of labour

A

latent
- mild irregular uterine contractions, cervix shortens + softens
- duration variable - may last uncomfortable few days

active
- 4cms onwards to full dilation
- progresses arounf 1cm an hour, regular contractions

17
Q

prolonged second stage criteria

A

In nulliparous considered prolonged if
>3hrs if there is regional analgesia or 2hrs without

Multiparous - >2hrs with regional analgesia, 1 without

18
Q

3 Ps in failure to progress

A

power = inadequate contractions (frquency/strength)

passages = short stature, trauma shape

passenger = big baby, head-pelvis ration, malposition

19
Q

3rd stage of labour

A

delivery of baby -> explusion of placenta + fetal membranes

average -> 10mins, can be 3+mins

after an hour, prolonged surgical removal

20
Q

prolonged 3rd stage criteria

A

active management >30mins
(use of oxytocic drugs + controlled cord traction)

passive/expectant management >60mins

21
Q

why is delayed cord clamping beneficial

A

immediate clamping can reduce RBCs an infant receives at birth by more than 50%

delayed –> more RBCs, less anaemia at 2months
- within 5mins - should be delay of 1-3mins

(unless immediate resuscitation is necessary)

22
Q

4 classic signs indicating separation of the placenta + membranes in 3rd stage of labour

A
  1. uterus contracts, hardens + rises into abdo
  2. umbilical cord lengthens permanently
  3. a gush of blood variable in amount
  4. placenta + membranes appear at introitus

(plane of separation = spongy layer of decidua basalis)

23
Q

active management of 3rd stage

A

IM oxytocin - helps uterus contract
careful traction of umbilical cord - guide placenta out

(shortens 3rd stage + reduced risk of bleeding - BUT assoc N+V)

24
Q

who is active management of 3rd stage offered to

A

all women at risk of PPH
if haemorrhage
or >60min delay

25
Q

braxton hicks contractions

A

occasional irregular contractions of uterus felt in 2nd or 3rd trimester
not true contractions - do NOT indicate onset of labour
irregular + DO NOT increase in frequnecy or strength

mx - relax + hydrate

26
Q

true labour contractions

A
  • under influence of oxytocin, which stimulates uterus to contract
  • timing of contractions become evenly spaced, time - - between gets shorter - length of them also increases
  • more intense + painful over time
27
Q

analgesia options for birth

A

paracetamol/co-codamol
TENS
entonoz
diamorphine
epidural

28
Q

partogram

A

graphic record of key data, both maternal + fetal
- used to assess progression of labour, dilatation, fetal heart beat

29
Q

3 key factor labour

A

Power - uterine contraction

PAssage - maternal pelvis

Passenger - fetus

30
Q

duration of contractions

A

initially 10-15secs, slowly builds up

31
Q

types of pelvis

A

anthropoid pelvis - oval inlet

android pelvis - triangular/heart shaped inlet, narrower

gynaecoid pelvis - most suitable **

32
Q

normal fetal position

A

cephalic presentation
occipito-anterior, head engages, flexed head

33
Q

7 cardinal movements in mechanism of labour

A
  1. descent - to pelvic inlet
  2. engagement - 3/5ths of fetal head enter pelvis, fetal head engaged when at widest diameter of fetal head has entered brim of pelvis
  3. flexion - chin against chest
  4. internal rotation - fetal shoulder rotate 45’
  5. extension + crowning - emerges from vagina, at level of interoitus

6, restitution - head externally rotates
7. expulsion - anterior then posterior shoulder

34
Q

how is haemostasis achieved post delivery

A

tonic contraction - lattice pattern of uterine muscle strangulates blood vessels

thrombosis of torn vessels - pregnancy is hypercoaguable state

35
Q

what is lactation initiated by post childbirth

A

by placenta expulsion + decrease in oestrogen + progesterone

(during pregnancy, oestrogen + progesteron inhibit milk secretion by blocking prolactin release + making amary glands unresponsive to it)

36
Q

preterm + postterm

A

pre-term <37wks

post-term - >42wks