Lecture 12: Childbirth Flashcards
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)
Obstetric Examination
- Use your eyes
- 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 - Use your ears: Fetal heart rate
- Use your mouth: ask for baby’s movements (movement is good, no movement can be either good or bad)
Presentations at term proportionately
95%: Head vertex (longitudinal lie)
4%: breech (longitudinal lie)
1%: oblique Shoulder presentation
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
Fetal heart rate
150-160 bpm
CTG cardiography
Has childbirth started?
childbirth has started when painful uterine contractions accompany dilatation and effacement of the cervix
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
What are the three mechanical factors that determine progression b/w the three stages of labour?
Baby structure, mothers structure and contractions
- Passenger (diameter of the baby’s head)
a) reference point b) *position c) attitude - Passage (dimension of the pelvis)
- Power (degree of force which expels the baby)
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)
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)
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
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
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
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
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”