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Flashcards in Mechanism and Management of Labour Deck (39)
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1

How many weeks gestation is considered 'term'?

37-42 weeks

2

What happens to the cervix as labour begins?

- Cervical ripening occurs at the end of pregnancy
- At term, cervix undergoes hypertrophy and an inflammatory-type reaction occurs

3

What are Braxton-Hicks?

Contractions that increase in frequency and amplitude as labour begins

4

Describe the first stage of labour

- 4cm to full dilation
- Latent Phase = painful contractions and cervical effacement
- Active Phase = regular painful contractions and cervical dilation
- Transitional Stage = towards end of 1st stage, change in behaviour (panic, fear, nausea, heavy show, shivering, urge to push)

5

How long is the 1st stage of labour?

Nulliparous = avg. 8h, max. 18h
Multiparous = avg. 5h, max. 12h

6

Describe the second stage of labour

- Full dilation to delivery
- Passive Phase = begins at full dilation prior to/ in absence of involuntary expulsive effort
- Active Phase = begins when baby is visible and involves maternal effort, pH of foetal blood decreases which increases risk of foetal hypoxia

7

How long is the 2nd stage of labour

Nulliparous = avg. 3h
Multiparous = avg. 2h

8

Describe the third stage of labour

- Delivery to expulsion of placenta
- Common complication = haemorrhage
- Clamping cord should be delayed for over 1 min to increase neonatal iron stores

9

What are the signs of placental separation?

- Gush of vaginal blood
- Lengthening of umbilical cord
- Rise in uterine fundus

10

Describe the management of the 3rd stage of labour

- Routine use of uterotonic drug (Syntocinon or Syntometrine)
- Controlled cord traction
- Clamping and cutting of cord

11

How long is the 3rd stage of labour?

Active management = 30 mins
Physiological management = 90 mins

12

What are the normal stages of labour?

1. Descent
2. Flexion
3. Internal rotation of head
4. Extension
5. Restitution
6. Internal rotation of shoulders
7. Lateral flexion

13

What is extension?

Foetal head escapes under the symphysis pubis and crowning occurs

14

What is restitution?

Head is delivered and rotates slightly externally

15

How do the shoulders rotate internally?

Anterior shoulder rotates forwards to sit under symphysis pubis in AP position

16

What is lateral flexion?

Anterior shoulder slips under pubic arch and over perineum - remainder of body born by lateral flexion through 3 pelvic planes (curve of carus)

17

What symptoms suggest that the woman should go in for an evaluation of labour?

- Possible rupture of membranes
- Regular contractions
- Vaginal bleeding
- Severe back, abdominal or pelvic pains

18

What observations should be taken during labour?

- Temp = 4 hourly
- BP = 4 hourly
- Pulse = hourly
- Freq. of contractions = 1/2 hourly
- Document freq. of emptying bladder
- Urinalysis and abdominal palpation = initial assessment

19

When should foetal heart auscultation occur?

1st stage = intermittently after most recent contraction every 15 minutes for 60 seconds (palpate maternal pulse to differentiate HRs)
2nd Stage = intermittently after most recent contraction every 5 minutes for 60 seconds

20

When should continuous electrical foetal monitoring be performed?

- Meconium stained liquor
- Abnormal foetal HR
- Maternal pyrexia (increased temp/ fever)
- Fresh vaginal bleeding
- Oxytocin
- Mother requests it

21

What is considered an abnormal foetal heart rate?

>160
<110

22

How should the midwife assess progress of labour?

- Strength and frequency of contractions
- VE every 4 hours

23

What are the 3 factors that influence progress?

1. Power
2. Passenger
3. Passages

24

How does power influence progress of labour?

Uterine contractions
- Established labour = 4 in 10 mins
- Delivery can be achieved with less uterine activity - don't measure progress by contractions alone
- Influenced by epidural anaesthesia, tocolytics and sedation

25

How do contractions affect heart rate?

More than 5 contractions in 10 mins = contractions compromise uteroplacental circulation = not enough oxygen = hyperstimulation = tachysystole

26

How does the passenger influence progress of labour?

- Progress influenced by foetal size and position
- Abdominal palpation required to access descent of presenting part
- Cervical assessment provides information about station of presenting part in relation to ischial spines

27

How do the passages influence progress of labour?

- Abnormality may cause delay
- Cephalopelvic disproportion = occurs with normal proportions of pelvis vs. macrosomic foetal head
- Rigid perineum may cause delay (may require episiotomy)

28

What are the NICE guidelines for delayed 1st stage of labour?

- Cervical dilation <2cm in 4 hours for 1st labours
- Cervical dilation <2cm in 4 hours or slowing progress for 2nd and subsequent labours
- Descent and rotation of head
- Changes in strength, duration and frequency of uterine contractions

29

Describe the interventions that should occur in delay of labour in 1st stage

- Support, hydration and effective pain relief
- Amniotomy if membranes are intact 2 hrs after VE
- Oxytocin if delay confirmed 2 hours after VE in nulliparoud
- Multiparous = full examination by obstetrician if delay 2 hours after VE
- If oxytocin required, transfer women to high risk care and cEFM

30

Describe the interventions that should occur in delay of labour in 2nd stage

- Intervene after 1 hour delay (4h nulli, 3h multi)
- Amniotomy if membranes are intact
- Consider further pain relief
- Examination by obstetrician required if delay is diagnosed
- Review every 15-30 mins
- Consider instrumental delivery/ CS
- NICE do not recommend use of oxytocin at this stage