Labour & Birth Flashcards
What causes the onset of labour?
Mechanical - when the uterus is overstretched
Cytokines/Prostaglandins (inflammatory markers that are stretched when the cervix is distally stretched)
How is the first stage of labour diagnosed?
When there are regular painful contractions and there is progressive cervical dilation from 4cm
Why should pregnant women not be examined flat?
Risk of postural supine hypotensive syndrome
What are the 4 components of an obstetric abdominal exam? (Any clinical exam)
Observation
Inspection
Palpation
Auscultation
What do you look for in the inspection part of obstetric clinical exam?
Abdominal mass
Stigmata of pregnancy (stretch marks)
Surgical scars
At what week do you start palpation in an obs exam? What are you palpating for?
From 36 weeks
Uterine size
From what week can the SFH be measured?
24 weeks
What’s effacement?
Shortening/thinning of the distal part of the cervix during childbirth
What are the different landmarks for the fundal height at different weeks?
Symphysis pubis at 12 weeks
Umbilicus at 20 weeks
Xiphisternum at 36 weeks
What’s the difference between foetal, transverse and oblique lie?
Foetal lie =long axis of the foetus and long axis of the uterus are longitudinal to the mothers
Transverse lie = when long axis of the foetus is perpendicular to the mother’s uterus
Oblique lie = long axis of the foetus is 90-180 degrees of the mothers uterus
What’s the ideal type of lie in foetal presentation?
Longitudinal lie - preferably cephalic presentation
What’s a cephalic presentation?
When the foetal head (vertex) is situated over the pelvis
What type of presentation could a transverse/oblique foetal lie result in?
Shoulder presentation
What are different types of breech presentation?
Extended or frank = legs up
Flexed or complete = as though baby is sitting
Footling = one or both legs extended at the hip
When is the foetal head ‘engaged’?
When the widest diameter of the head (biparietal diameter) has passed through the pelvic brim
When 2/5 of the head are palpable at the angle between the head and symphysis pubis
Why is abdominal palpation of the foetal head assessed in fifths, what does this mean?
Measuring foetal head engagement
3/5 of the head are abdominal palpable = not engaged
2/5 or less = engaged
What does attitude relate to?
The relationship of the foetal head and limbs to its body:
Fully flexed (ideal)
Deflected
Partially extended
Completely extended
What should be included in the obs pelvic examination?
Not routinely done
External examination of the vulva
Internal inspection of the vagina and cervix
Vaginal examination if indicated
How many cm is one finger breadth? How many cm is the 1st stage of labour?
1-1.5 cm = 1 finger breadth
Dilated to 4cm
What’s happening to the cervix during effacement?
Dilates
Length: shortens (from 3cm) as it becomes part of the lower segment of the uterus
Position of cervix becomes more anterior
Consistency becomes softer
The station of presenting part is determined by how much the presenting part has descended into the pelvis (fixed point is ischial spines and can be used)
Position of presentation part: with a cephalic presentation, the anterior and posterior fontanelles and sagittal sutures should be identified
What does station refer to?
Relationship of the presenting part to an imaginary line drawn between the ischial spines of the maternal pelvis
What’s the Bishop score?
Evaluates ‘ripeness’ or favourability of the cervix - the higher the score the more favourable the cervix
How is the progress of labour assessed?
Uterine contractions
Dilation of the cervix
Descent of the presenting part
What’s used to assess progress of labour? How is slow progress indicated?
Partogram
Slow = lack of cervical dilation and failure of descent of the presenting part
What are the 3 stages of labour?
1st stage: onset of regular contractions-> full dilation to 10cm of cervix
2nd stage: full dilation of cervix -> birth of baby
3rd stage: birth of baby -> delivery of placenta, membranes and control of associated bleeding
What stage in labour is the baby born?
2nd stage (once the cervix is fully dilated, at 10cm)
What’s meant by: powers, passage and passenger? (3Ps)
Powers = contractions (strength, length, frequency, effectiveness)
Passage = birth canal (bony pelvis, adaptation, soft tissues, pelvic floor, cervix, vagina, vulva)
Passenger = size/positioning/coping
All 3 interact for successful outcome
What’s the mechanism of delivery in the 1st stage of labour?
Flexion of the head as the cervix is effacing and dilating
What’s the mechanism of delivery during the 2nd stage of labour?
Internal rotation: head reaches pelvic floor, occiput into anterior position
Extension: foetal head is delivered under pubic symphysis
External rotation: head distends the perineum, allows delivery of the shoulders
What’s induced labour?
Artificial initiation of uterine contractions prior to spontaneous onset
How many women will require induced labour?
1 in 5 deliveries
What are the consequences of induced labour?
Affects birth experience
May be less efficient
Usually more painful - epidural analgesia required
Why would labour be induced? (Maternal and foetal reasons)
Maternal: severe pre-eclampsia, recurrent antepartum haemorrhage, diabetes
Foetal: prolonged pregnancy, IUGR, rhesus disease
What’s Rhesus disease?
Condition where antibodies in pregnant woman’s blood destroy baby’s blood cells (haemolytic disease of the newborn) = anaemic and jaundice
What needs to be assessed for induction?
Favourability of the cervix using Bishop score
Favourable cervix = soft, beginning to dilate and efface
What are the main methods or induction?
Prostaglandins eg Dinoprostone by local application (vaginal gel, tablet or pressary) and used to ‘ripen the cervix’
Amniotomy causing local release of endogenous prostaglandins
IV induction of synthetic oxytocin (Synctocinon) strength is titrated against strength and frequency of contractions
What’s a risk of prostaglandin (dinoprostone PGE2) use in induction?
Uterine hyperstimulation = 5 contractions in 10 minutes
Why would you intervene operatively in labour?
If there’s a delay in 1st or 2nd stage Suspected foetal distress Ante-partum haemorrhage Breech Severe IUGR Twins
Maternal reasons: HIV, raised ICP, pre-eclampsia
How is pre-eclampsia diagnosed?
Validated 24 hour urine sample and proteinura >300mg
What can you use in operative interventions in delivery?
Ventouse = cup shaped suction to baby head
Forceps
Episiotomy = increase diameter of pelvic outlet
Caesarean section
What are the 2 ways to monitor the foetus during labour?
Intermittent auscultation using a Picard stethoscope or Doppler
Continuous cardiotocographausc monitoring
How often is intermittent auscultation of the foetus during labour done?
Used for all healthy women with non-complicated pregnancies
In the 1st stage of labour: for 1 minute immediately after a contractions and at least every 15 minutes
In 2nd stage: every 5 minutes and after a contraction
What’s meconium? Meconium aspiration syndrome?
The first stool, blackish green and tenacious (if present in liquor is can be indication of foetal distress)
Aspiration of the stained amniotic fluid - causes severe respiratory distress in the newborn, but it’s sterile so can’t cause bacterial pneumonitis
What’s done during the 3rd stage of labour? (There are 2 ways)
Physiological: no drugs, wait for passive delivery of placenta and don’t cut the cord until it stops pulsating
Active: use synthetic oxytocin into the thigh, clamp and cut the cord
What can meconium in the amniotic fluid indicate?
Serious disease
What are the advantages of having active management of stage 3 labour?
It shortens the third stage, for anyone who had a distressing labour (previous stages)
Associated with a lower risk of blood loss
Associated with lower risk of requiring blood transfusion
What are some causes for a ‘larger than dates’ or smaller measurements of symphysio-fundal height?
Larger: multifetal pregnancy, polyhydramnios and diabetic pregnancy
Smaller: intrauterine growth restriction
