Lecture 12: Childbirth Flashcards Preview

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Flashcards in Lecture 12: Childbirth Deck (32):
1

Childbirth

process whereby the baby + placenta are expelled from the uterus
1. Assembly line: First 12 weeks
2. Development and Maturation: 12wks onwards
3. End stage: Childbirth 37-42 weeks gestation
Mainly in hospital (less than 1% born at home)

2

Obstetric Examination

1. Use your eyes
2. Use your hands:
a) Gestational age (fundal height: top of symphysis to fundus)
b) Fetal lie: long axis pf the baby to the uterus (longitudinal, transverse, oblique)
c) Presentation: Part of the fetus which occupies the lower segment of the uterus (cephalic(vertex), breech, shoulder)
d) Engagement: depth of the presenting part in the bony pelvis
3. Use your ears: Fetal heart rate
4. Use your mouth: ask for baby's movements (movement is good, no movement can be either good or bad)

3

Presentations at term proportionately

95%: Head vertex (longitudinal lie)
4%: breech (longitudinal lie)
1%: oblique Shoulder presentation

4

Engagement

depth of the presenting part in the boney pelvis
palpate the abdomen
Not engaged: still able to move head
Engaged: little head movement --> already started decent in preparation for delivery

5

Fetal heart rate

150-160 bpm
CTG cardiography

6

Has childbirth started?

childbirth has started when painful uterine contractions accompany dilatation and effacement of the cervix

7

Stages of labour

First stage: cervix opens to full dilatation (cervix becomes shorter = effacement (still closed)
Second stage: full dilatation --> delivery (cervix not closed)
Third stage: delivery of baby --> delivery of the placenta
-Progress is determined by 3x mechanical factors

8

What are the three mechanical factors that determine progression b/w the three stages of labour?

Baby structure, mothers structure and contractions
1. Passenger (diameter of the baby's head)
a) reference point b) *position c) attitude
2. Passage (dimension of the pelvis)
3. Power (degree of force which expels the baby)

9

Passenger Reference Point

Baby's head is the largest part to negotiate the birth canal
- Head isnt round.
Bone's arent yet fused --> can move according to the requirements of the passage (sutures and fontanelles)

10

Passenger's skull feautres

Suture: inb/w differentbones. Alot of elastic CT --> helps to negotiated boney pelvis
Fontanelle: sutures come together
Occiput: point of reference for location of baby's head (determines progress of labour)
- vaginal examination to see how DEEP the baby's head has advanced and POSITION of the head (can feel for the occiput)

11

Sagital suture and Anterior/Posterior fontanelle

Sagital suture: separates 2x parietal bones
Anterior fontanelle: bordered by 2x frontal and 2x Parietal bones
Posterior fontanelle: bordered by 1x occipital and 2x parietal bones

12

Passenger Position

Degree of rotation of the head
boney pelvis = transversely oval shape
Need toturn head whilst in boney cavity in order to manipulate outlet
Entering inlet of pelvis: Beginning of labour is best as the head of the baby enters the pelvis transversely
Exiting outlet of pelvis: oval shape but the other way

13

Passenger attitude

Degree of head flexion (head is oval)
Optimal: maximal flexion (occipital in midline/on back side) --> smallest diameter 9.5cm
Extension is unwanted as results in largest diameter (occipital on side):
- Extension 90 degrees = Brow 13cm
- Extension 120 degrees = Face

14

Passage's boney pelvis

Inlet: wider transverse diameter
Mid cavity: round (Bend --> must carefully negotiate turn)
Outlet: wider AP diameter
--> need to rotate head within cavity in order to get out
vs. animals walking on all fours --> boney pelvis is straight --> easier birth

15

Passage's boney pelvis reference point

Ischial Spines, palpable structures in the lateral wall of Mid cavity
Compare how far the baby has moved relative to the ischial spines of the mid cavity (assess descent of the head on vaginal examination)
Head located above ischial spines (-2, -1): wont be born naturally --> C-section
Head located below ischial spines (0, 1, 2) --> born through natural vaginal birth --> engaged
Level of descent if called "Stations"

16

Units for Passage's boney pelvis reference point

-2, -1, 0, 1, 2
0 = ischial spine
Never try to assist woman in birth if head is still above 0/ ischial spines --> better for baby to have c-section

17

Power mechanical factor determining progression of labour

Regular and Painful Contractions (degree of force expelling the baby)
Once labour is established, the uterus, under the influence of OXYTOCIN, contracts for 45-60 seconds, every 2-3 mins

18

Management and Maintenance of childbirth progression

Partogram
-document of bay's progress: HR, dilatation
- Alert line if progress is slow
-Action line if action needs to be taken immediately

19

Steps in Normal labour

1. Initiation & Diagnosis
2. First, Second & Third stages

20

Initiation and Diagnosis stage in Labour

1. overall
a) Contractions
- Braxton-Hicks contractions (irregular, but become increasingly powerful)
- Prostaglandin production (relaxation of cervix)
- Oxytocin release from posterior pituitary
b) Effacement of the cervix
c) show

21

First stage of Labour

2. overall (Onset of cervical dilatation)
a) dilatation: Latent phase (first 3cm of dilatation)
- rate: nulliparous woman 1cm/hour and multiparous woman 2cm/hour
b) contractions: regular and painful
c) descent, flexion and internal rotation: through boney pelvis. occurs to a varying degree.
d) effacement
e) rupture of membranes (release of liquor)

22

Second stage of Labour

3. overall (Full cervical dilatation --> delivery)
a) contractions: regular and painful
b) descent, flexion and internal rotation Complete: successful been able to negotiate the boney pelvis
c) Passive stage: Occurs until head reaches pelvic floor --> mother experiences desire to push
d) Active stage: irresistible desire to bear down. nulliparous woman 40-60min and multiparous woman 20-30min (shorter if have already had vaginal birth)

23

Delivery stage of Labour

4. overall
- Baby's head reaches perineum --> extends to come out of pelvis --> tear/episiotomy --> crowns --> born
- Head then restitutes rotating 90 degrees in transverse position (back to the world) in which it entered the pelvis again (everything follows)
- Anterior shoulder comes under the symphysis first
- rest usually follows

24

Third stage of labour

5. overall (after baby's birth/delivery --> placental delivery, with normal uterine contraction)
Uterine contractions compress the (maternal) Blood vessels which used to supply the placenta --> Placenta shears away from the uterine wall --> Placenta is delivered
- active and physiological management can occur to aid placental delivery
- Active Mx minimises haemorrhage

25

Active management of the third stage of labour

Ecbolic injection (Massive oxytocin injection causing uterine contraction)
Early clamping and ligation
Controlled cord traction

26

Physiological management

Not clamping cord until pulsations cease
No traction
Expulsion of placenta by maternal effort

27

Slow progress of childbirth

Slow progress: <1cm/hour dilatation
Prolonged labour: >12 hours duration
Aietiology: P, P, P - if something goes wrong it is due to the 3x P's

28

Aietology behind Slow progress/Prolonged labour

Passanger: a) fetal size (gestational diabetes) b) disorder of rotation OP/OT
- OP = occipital posterior = help required
Power: insufficient uterine contractions
- requires augmentation (oxytocine)
Passage: Cephalo-pelvic disproportion

29

Aietiology behind Fetal size causing slow progression/prolonged labour

Current problem: Gestational diabetes
- current epidemic
- mother cannot control her sugar intake during pregnancy --> Huge baby develops

30

What types of delivery is there?

1. Vaginal ( if baby is above station 0, +1, +2, +3)
2. Instrumental
3. Caecerean

31

Instrumental Delivery

Low and mid cavity
1. Forceps: possibly quicker. more maternal birth canal injuries and more neonatal nerve palsies
2. Ventouse: rotation possible. more neonatal cephalhaematomas

32

Caesarean Delivery

Assist mother or baby
sometimes used to decrease discomfort, especially during first birth
Note: natural birth is still very good and there are ways to decrease pain. Giving birth is a highlight of many mothers lives, and no fear of doing an "incomplete job"