Obstetrics Flashcards
What is normal labour? Diagnosis made when?
Process where foetus and placenta are expelled from the uterus
Painful uterine contractions accompany dilation and effacement of the cervix
What mechanical factors affect labour? 3 Ps
Powers - degree of force expelling
Passage - dimension of pelvis and resistance of soft tissues
Passenger - diameter of fetal head
What are Braxton-hicks contractions?
Painless uterine contractions that occur at intervals from 30th week
Can be palpated
Who often has poor powers (uterine activity)?
Nuliparous
Induced labour
What are Montevideo units? How are they calculated? How can you measure them?
Measure of uterine activity
Intensity of contraction x frequency of contraction (per 10 mins)
Can be measured using a cardiotocograph (CTG)
Where is the pacemaker of the uterus found?
Junction of Fallopian tube and uterus on 1 side
What physiological change do the coordinated contractions of labour cause? What does this cause?
Permanent shortening of the muscle fibres
-> distension tension on less muscular lower part ESP. Cervix
What causes the pain in contractions ?
Ischemia in myometrial fibres
What factors are associated with abnormal lie?
Polyhydroaminios, high parity, fetal/uterine abnormalities, conditions that prevent engagement (placenta previa, pelvic tumours, uterine deformities)
Preterm
What position in extended breech?
Buttocks present and legs are extended so by head
What does presentation refer to?
The part of the foetus that occupies the lower segment of uterus or pelvis
How common is abnormal lie ?
1/200
Where provides the strongest contractions to push fetes along?
Upper uterine segment
3 main parts of passage ?
Bony pelvis - inlet, mid cavity, outlet
Ischia spine - used to assess decent
Soft tissues - cervical dilation, vagina and perineum need to be overcome in second stage
Bony pelvis …
Shape of the mid cavity?
AP diameter of outlet?
What does station 0 mean?
Round
12.5cm (transverse is around 11cm at this point)
The head is at the level of the ichial spines, approximately mid cavity (+ve means head below spines -ve means above)
Does the coccyx obstruct labour? What can happen after birth?
No
Alteration in its position can cause pain
Which presentation do you want? Presentation if a 90 degree extension ? 120 degree? What presentation does the head normally deliver in ?
Vertex - narrowest diameter (9.5cm)
Brow (13cm)
Face
Occipito-anterior
What is ‘attitude’ in relation to foetus?
Degree of flex ion of head on neck (you want maximal - vertex presentation)
Think chin to chest
3 stages of labour? What happens in each?
1- initiation to full cervical dilation
- Latent phase - slow dilation up to 3cm
- Active phase - average 1cm/hr (could be 2cm/hr in multiparous)
2 - full cervical dilation to delivery of foetus
- passive - full dilation till head reaches pelvic floor -> desire to push
- Active - mother pushing (epidural effect)
- delivery of foetus to delivery of placenta
- normally 15 mins
Can have traditional or active management
- delivery of foetus to delivery of placenta
How do epidurals affect labour
Remove desire to push -> longer labour
What happens in traditional (expectant) management for 3rd stage of labour?
Active management ?
Light massage of uterus though abdo -> encourages contraction
IM - Syntocinon (syntometrine)
What levels of blood loss are normal in delivery?
500ml in vaginal
1000ml in C section
What aids identification of an abnormal process in labour
Partogram - graphic representation of labour with key observations
What is the most common cause of slow progress in primiparous labour?
Inefficient uterine action
In multiparous women with slow labour progress what are you worried about?>
Malposition -> uterine rupture more likely
What should you do with hyperactive uterine contractions and vaginal bleeding with fetal heart rate abnormalities?
C section
When is tocolysis usually used ?
Iatrogenic Uterine hyperactivity - Eg Prostaglandin administration
Why is eating discouraged during labour? What is this called?
Stomach contents can be aspirated
Under anaesthetic called Mendelson’s syndrome
What urinary issue should you consider during labour?
Retention - if neglected -> irreversible damage to detrussor
During the general care of labour, some general care things you should think of?
Physical health - obs, mobility, delivery positions
Mental health - environment, control, partner, birth attendant
What to do in persistent inefficient uterine action?
Augmentation (ARM artificial rupture of membranes)
What is associated with hyperactive uterine action? What does it ->?
Placental abruption, too much oxytocin, PG side efffect
Fetal distress as blood flow diminished
Management of hyperactive uterine action?.
No evidence of abruption -> tocolutic Eg salbutamol (IV/SC)
Usually LSCS due to fetal distress
What is augmentation? Egs?
Artificial strengthening of contractions in established labour
ARM, Amniotomy, artificial oxytocin
Nuliparous with slow first stage? Poor decent in passive second stage? Longer than 1hr in active second stage?
Augmentation, if no full dilation by 16hr -> c-section
P2nd - oxytocin infusion
A2nd - >1hr spontaneity’s delivery unlikely -> episiotomy, ventouse / forests
Rare problems with passage?
Cephalo-pelvic disproportion
Pelvic variants and deformities
How often do you auscultation fetal heart rate?
Every 15mins in first stage
Every 5 mins in second stage
Intrapartum fetal problems
Meconium aspiration
Fetal blood loss
Trauma
Infection (group B strep)
What is fetal distress? 3 Egs of signs?
Hypoxia that might result in fetal damage or death if not reversed / foetus delivered urgently
Colour of meconium, fetal heart rate auscultation, CTG, Fetal ECG, Fetal blood (scalp) sampling
CTG (cardiotocography) mnemonic
DR C BRAVADO Define Risk Contractions per 10 mins (<5) Baseline Rate (110-160) Variability - variation in fetal heart rate should be >5bpm Accelerations - with movement / contraction is reassuring Deceleration Overall assessment
What might fetal tachycardia indicate? Bradycardia?
Fever, fetal infection, hypoxia
Sustained deterioration in rate -> acute fetal distress
What does a prolonged reduced variability in fetal heart rate suggest?
Hypoxia