22 - Child Birth Flashcards
What do I need to know?
- Describe the examination of the pregnant abdomen
- Diagnose the onset of labour
- Describe the 3 stages of labour
- Demonstrate the normal progress in labour and descent of the fetal head through the maternal pelvis
- Explain the possible causes of slow progress in labor (3 Ps)
- Outline abnormal delivery methods
Childbirth definition
Childbirth is the process where BOTH the baby and the placenta are expelled from the uterus
When does childbirth normally occur? i.e. when is term?
37-42 weeks is considered term but most commonly the average is 39-40 weeks
Use your eyes?
Big stomach
- high bmi?
- abdominal tumor? very rare under 45
- pregnant; check for any scars of previous caesarian as this impacts on labour
Use your hands?
- palpate the abdomen to feel the fundus/top of the uterus
- feel the fetus and the fluid volume
Fetal lie?
Fetal lie is the relation of the long axis of the baby to the uterus (which way the baby is lying essentially)
What is the most common fetal lie?
Longitudinal lie (others are transverse and oblique)
How do you measure fetal size/gestational age?
Measure fundal height/how far the fundus is from the pubic symphysis
Presentation?
Presentation describes the part of the fetus that occupies the lower segment of the uterus i.e. the part that is presenting to the outside world
> i.e. vertex/cephalic, breech (bottom first), shoulder
> most common is longitudinal lie with cephalic presentation, also get longitudinal lie with breech presentation and transverse lie with shoulder presentation (can’t deliver vaginally)
Engagement?
Engagement refers to how deep the presenting part of the fetus is engaged in the bony pelvis
- 0 is taken by the ischial spine (pelvic brim/pubic symphysis and is unengaged)
- split into 5ths (if 5/5ths is palbale abd/above pelvic brim then is not engaged)
- tells you about progress of labor
What 4 things does using your hands help you with?
- Gestational age/fetal size
- Presentation
- Engagement
- Fetal lie
Use your ears?
- fetal heart rate
> US doppler looks at the HR in the moment (110-160bpm)
> external fetal monitor looks at the HR over time and shows it on a trace over a period of hours OR weeks of pregnancy
What is a normal fetal HR?
110-160 BPM
Use your mouth?
Ask about the babies movements (movement is good)
What does an obstetric examination include?
Observation Palpation > fetal lie > presentation > engagement Fetal heart rate Baby's movements
When has childbirth started?
Childbirth has started when painful uterine contractions begin AND there is both effacement and dilation of the cervix
Effacement of the cervix?
Reduction in thickness of the cervix
Childbirth starts when..
Painful uterine contractions (oxytocin) and there is both effacement and dilation of the cervix
How many stages is labour divided into?
3
First stage of labour
The first stage of labour is where the cervix opens to full dilation
Begins long and undilated then becomes thin and 10cm fully dilated
Which stage of labour is the longest?
First
Second stage of labour?
Second stage of labour is from full effacement and dilation to delivery of the fetus
Third stage of labour?
From delivery of the baby to delivery of the placenta as it separates from the maternal surface
What is progress of labour determined by?
3 mechanical forces determine the progress of labour
What 3 mechanical forces is the progress of labour determined by?
Passenger (diameter of the babies head - as is widest part of the body)
Passage (dimensions of the pelvis)
Power (degree of force expelling the baby/force of contractions)
Passenger?
Baby’s head is widest part to negotiate the birth canal. Breech has increased risk as it means the largest part of the baby exits last.
Baby’s head?
Is not round. Bones are not fused and so have sutures (gaps) and fontanelles (where more than 2 bones meet) to allow the bones to overlap and reduce the diameter of the head
Describe the bones of the baby’s head
- 2 parietal bones
- occipital bone
- 2 frontal bones
> frontal suture
> coronal suture - anterior and posterior fontanelle
- sagittal suture
What is the occiput?
Back of the head (occipital bone). Is the reference point. Should be the lead point of the baby’s head. Is used to describe the position of the baby’s head - felt by doing a vaginal digital exam
Passenger
- position?
Passenger position describes the degree of rotation of the baby’s head
- the widest part of the pelvic inlet is transverse and so the baby’s head will be in the transverse position
- mid-pelvis is circular so there is rotation of the fetal head
- pelvic outlet is widest ant>post so get rotation of fetal head having the occiput anterior and the fetal head is facing downwards
Passenger
- attitude
Attitude is the degree of flexion of the baby’s head
- degree of flexion/attitude impacts on the diameter of the head
- maximum flexion occurs when the baby’s head is on its chest and this causes the smallest diameter of the baby’s head and so is the ideal attitude
Ideal attitude?
Maximal flexion where the baby’s chin is on its chest and the occiput is the presenting part (9.5cm with max dilation of the cervis being 10cm!!)
Widest attitude?
When the baby is looking straight ahead/extended 90 degrees (brow presentation - occiput not coming out first is the forehead - 13cm and won’t fit)
What 3 things do we want to know about the passenger?
- Presentation (lowest part of the fetus palpable on vaginal examination)
- Position (degree of rotation of the head with ref to occiput)
- Attitude (degree of flexion of the head)
Passage
- bony pelvis dimensions
inlet - wider transverse diameter (head off to one side)
- mid cavity - round
- outlet - wider AP diameter (face down)
> head goes through a 90 degree rotation
Passage
In the lateral wall of the mid cavity the ischial spines are palpable on digital vaginal exam - is the reference point for the mother i.e. how far away from the ischial spines is the fetal head?
- ischial spines is the 0 ref point to how deeply the head is engaged (level of descent is called STATION -2, +2…)
Power
- degree of force expelling the baby
- there are contractions in the abd that push the baby DOWN (i.e. fundal contractions) and that pull the cervix UP
Contractions?
Once labour is established the uterus under the influence of oxytocin contracts for 45-60 seconds every 2-3 minutes. This can last hours. Regular, painful contractions
Normal labour
- initiation and diagnosis
Contractions
> irregular/non-painful contractions are called Braxton-Hicks contractions occur in 3rd trimester
> prostaglandins are produced which cause relaxation, softens and opens the cervix
> oxytocin is released from the posterior pit
Effacement of the cervix
First stage of normal labour
- regular painful contractions
- effacement
- dilatation (2 phases)
- fetal descent, flexion and internal rotation
- there is usually rupture of membranes and release of liquor
What are the 2 phases of dilatation
Latent phase
- dilation of the first 3cm of the cervix. Can take hours
Active phase
- dilation of last 7cm
- both mum and baby are working hard and so this is when things are most likely to go wrong (is faster in mums that have had a previous birth)
> cm/hour or 2cm/hr
Normal labour
- Second stage
- contractions
- fetal descent, flexiona dn internal rotation are completed
> passive stage: Is till the head reaches the pelvic floor and the mother then experiences the desire to push
> active stage: Experience the irresistible desire to bear down (quicker in multiparous women 30mins>1hour)
Passive stage of 2nd stage of normal labour?
Till the head reaches the pelvic floor and then the mother experiences the desire to push
Normal labour
- delivery
- As the baby’s head reaches the perineum it EXTENDS to come out of the pelvis, CROWNS (may tear) and is born
- the head then restitutes rotating 90 degrees to adopt the transverse position in which it entered the pelvis again
- the anterior shoulder comes under the symphysis first and the rest of the body follows
Placenta delivery
Uterine contractions (become tonic) compress the BVs that supplied the placenta which shears away from the uterine wall.
What are the 2 types of placenta delivery?
- Active management
> ecbolic injection (encourages the tonic uterine contraction). Early umbilical cord clamping and ligation, controlled cord traction to help the placental separation to occur (redcues risk of haemorrage) - Physiological management
> NOT clamping the cord until pulsations stop. No traction. Expulsion of placenta by maternal effort. Takes longer.
Abnormal labour?
- slow progress where there is less than 1cm dilation and hour
- or prolonged labour that takes longer than 12 hours
Abnormal labour
- power
- passenger
- passage
Power: May be insufficient uterine action (give oxytocin -augment)
Passenger: Fetal size or disorder of rotation i.e. occiput posterior [looking up] (increasing contraction strength can also help this)
Passage: Cephalo-pelvic disproportion
What needs to have happened for an instrumental birth to be safe?
Fully dilated and down far enough. Widest part of the baby’s head has to of gone past the smallest diameter of the mother’s diameter (know it will fit!)
Low and mid cavity
Forceps?
Cradle around the baby’s head. Possibly quicker, more maternal injuries as increasing diameter of head, more neonatal facial nerve palsies
Ventouse?
There is less force able to be produced compared to forceps and so is more likely to be unsuccessful. More bruising on head. Rotation possible. Suction cup on head - not increasing diameter.
What % of baby’s are born by caesarian?
30%
