Normal labour Flashcards

1
Q

Definition/Diagnostic criteria of true labour

A
  1. Regular, painful uterine contractions
  2. Increasing frequency and intensity
  3. Cervical effacement (shortening of cervix until indistinguishable from uterine wall)
  4. Progressive cervical dilatation (≥3cm is active)
  5. Descent of fetal presenting part in the pelvis
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2
Q

False labour

A

aka Braxton-Hicks’ contractions
- Irregular uterine contractions that are not of increasing frequency or intensity
- Last 4-8 weeks of pregnancy
- Normally painless, unpredictable and spontaneous
- Not a/w progressive cervical dilation or effacement

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3
Q

2nd stage of labour

A

From full dilatation to delivery of fetus
- primigravida: ~2h
- multigravida: ~1h
+ 1 hour if epidural given (no pressure from descending fetus -> passive descent of fetus, allow mom to regain sensation to push)

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3
Q

1st stage of labour

A

From onset of painful REGULAR uterine contractions to full dilatation of cervix (10cm)
- Divided into 2 phases: Latent vs Active
- Monitor descent of fetal head

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4
Q

3rd stage of labour

A

From delivery of the fetus to delivery of placenta
- Up to 30 mins in both nulli and multiparous women

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5
Q

Changes to mommy preceding labour

A
  1. False labour pains (braxton hicks)
  2. Lightening
    - Fundal height drops a bit as baby drops into pelvis -> feels a bit easier to breathe
  3. Discharge of mucus plug
  4. Cervical changes (effacement and dilatation)
  5. Show
    - Can be blood-stained mucoid plug
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6
Q

What is ‘the show’ in labour?

A

Loosening and expulsion of the mucus plug that has been blocking the cervical canal during pregnancy

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7
Q

Duration of 1st stage of labour

A

Primigravida: 12h
Multigravida: 6h

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8
Q

1st stage of labour: Latent phase (variable)

A
  • Effacement of cervix
  • Dilatation of cervix from 0-3cm
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9
Q

1st stage of labour: Active phase (2-9h)

A

Rapid dilatation of cervix from 3-10cm with regular uterine contractions
-> Nulliparous women: 1cm/h
-> Multiparous women: 2cm/h
- Entire cervical length is retracted into LUS
- Ensure delivery 12h from now
*if uterus keeps contracting too much, this can cause uterine atony -> PPH -> rupture

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10
Q

If progress of cervical dilatation is <1cm/h for normal primiparous women, consider:

A

Uterine dysfunction
Fetal malposition
Cephalopelvic disproportion

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11
Q

Monitoring descent of fetal head

A
  1. Crichton’s method: Abdominal palpation - in “fifths”
  2. Vaginal examination: “Station” relates the level of the lowest point of fetal head with ischial spine
    *Eg. 1cm above/below ischial spine is +1/-1 etc
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12
Q

What is LIE?

A

Relationship of longitudinal axis of the fetus to
the longitudinal axis of the mother
- longitudinal vs transverse vs oblique

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13
Q

What is PRESENTATION?

A

Part of the fetus directly overlying the pelvis
- cephalic vs breech vs shoulder
- cannot tell on abdo palpation

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14
Q

What is PRESENTING PART?

A

Part of the fetus that is
felt through the cervix on vaginal examination
- If baby is fully flexed, means baby is in cephalic presentation: first contact point is vertex
- If baby is fully extended, means baby is not in cephalic presentation: first contact point is face

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15
Q

What is POSITION?

A

An arbitrarily chosen portion of fetal presenting part described in relation to mother’s left/right, ant/posterior of birth canal
- For cephalic presentation with vertex as presenting part: use OCCIPUT as chosen point

16
Q

Mechanics of labour - 3Ps

A
  1. Passage: Bony pelvis, soft tissue of the uterus (cervix and pelvic floor muscles)
  2. Powers: Uterine contraction
  3. Passenger: Fetus

If passenger is too large or passage is too small –> Cephalopelvic disproportion

17
Q

Passage: Bony pelvis, soft tissue of the uterus (cervix and pelvic floor muscles)

A
  • Gynaecoid pelvis (most common and best for vaginal delivery)
  • Platypelloid and android pelvis (can cause obstructed labour)

If passenger is too large or passage is too small –> Cephalopelvic disproportion

18
Q

Passenger: Fetus
Features that can affect labour

A
  • Number of fetus
  • Size
  • Lie
    -> Longitudinal: Normal vaginal delivery possible  
    -> Oblique, transverse: NVD not possible  
  • Presentation
    -> Cephalic: Vertex best presentation, NVD possible
    -> Shoulder: NVD not possible
    -> Breech: Attempt maneuvers, if not caesarian section preferred
  • Position
  • Station
  • Anomalies (eg. hydrocephalus, sacrococcygeal teratoma)

If passenger is too large or passage is too small –> Cephalopelvic disproportion

19
Q

Powers: Uterine contraction

A
  • dilate cervix
  • push fetus through birth canal
  • assessed by CTG or palpation of uterine fundus through maternal abdomen
  • freq: 2-4/10 mins
  • intensity increases over time
  • duration ~20s in early labour and 40-90s in active phase

2’ power: Maternal effort

20
Q

Mechanism of labour: 7 foetal cardinal movements in labour

A
  1. Engagement
  2. Descent
  3. Flexion
  4. Internal rotation
  5. Extension
  6. Restitution
  7. External rotation
21
Q

Engagement

A

When the widest diameter of fetal presenting part is through the pelvic inlet
- Cephalic presentations: Biparietal
- Breech presentations: intertrochanteric

Based on the Crichton’s method, when the head is 3/5ths or more palpable = engaged!

Usually engages in L occiput anterior position

22
Q

Descent

A

Downward passage of presenting part within maternal pelvis

23
Q

Flexion

A

While descending through pelvis, fetal head meets resistance against pelvic floor muscles and shape of bony pelvis and will flex (fetal chin is touching fetal chest)
- functionally creates smallest sagittal diameter to pass through the maternal pelvis

24
Q

Internal rotation

A

With further descent, the occiput rotates anteriorly and the fetal head assumes an oblique orientation
- Most common: Left occiput anterior position (back of baby’s head towards mother’s left thigh)

25
Q

Crowning

A

Widest diameter of the fetal head has successfully passed the narrowest part of the maternal bony pelvis
- Fetal head visible at perineum

26
Q

Extension

A

After crowning, fetus head descends to the level of introitus

27
Q

Restitution, external rotation

A

After fetal head extends, it rotates to the correct anatomic position in relation to fetal torso.
- A passive movement resulting from a release of the forces exerted on the fetal head by the maternal bony pelvis and its musculature

28
Q

Expulsion

A

Delivery of rest of foetal body, first with anterior shoulder of the fetus just below pubic symphysis, then posterior shoulder and the rest of the body

29
Q

3rd stage of labour: Signs of placental separation

A
  1. Lengthening of cord (suggests placental is descending down)
  2. Fresh gush of blood due to rich vascular supply of uterus
  3. Uterus rises in abdomen (suprapubic bulge/ level of umbilicus)
  4. Uterus becomes firm and globular (contracted, forms a hard mass)
30
Q

Delivery of placenta

A
  1. After baby delivered, umbilical cord is cut between clamps
  2. Administer ergometrine‐oxytocin (IM Syntometrine) parentally to cause uterine contractions and facilitate delivery of placenta + prevent PPH
  3. Deliver placenta by controlled cord traction (one hand pull cord down, other hand hold uterus up)
    - STOP if resistance felt -> means uterus is getting pulled, may get inverted
    - STOP if cord snaps
31
Q

Post placental delivery

A

Adequate analgesia
Perineal toilet
Surgical repair
- perineum tear during crowning or
- mediolateral episiotomy made prior to crowning

32
Q

Monitoring of labour

A
  • Maternal wellbeing (partogram)
  • Fetal wellbeing (CTG)
  • Progress of labour (rate of cervical dilatation on partogram)
33
Q

Maternal monitoring: Partogram

A

Documents mothers progress in labour
Started once diagnosed to be in labour
Allows effective comms between staff

  1. Vital signs:
    - Temperature
    - Pulse
    - Blood pressure
    - Input - output
    - RR
  2. Contractions
  3. Effacement & descent
  4. Fetal heart rate
  5. Pain relief and hydration
34
Q

Partogram: Rate of cervical dilatation

A

Parallel lines drawn on the partogram at the
time of first vaginal examination in active
labour:
- Alert line is drawn from the point of cervical dilatation noted at first vaginal examination at
a slope of 1 cm per hour
- Action line is drawn 4h to the right of alert
line

35
Q

How to assess for abnormal labour via partogram?

A

Review every 3-4h  
- Expect 6cm at 11am (After 1st examination at 8am)  
- If at 11am, only 4cm, means progress is inadequate: Primary arrest of labour  
- If initial progress is adequate but later halted: Secondary arrest of labour
- if patient continues to follow alert liine -> proceeding to normal delivery

36
Q

Pain relief in labour

A
  • TENS, acupunture
  • ‘Etonox’ (50% O2, 50% nitrous oxide mixture)
  • Pethidine, morphine
  • Epidural analgesia