Malpresentation, failure to progress in labour Flashcards
What is term in normal pregnancy?
37-42 weeks
What are the 3 mechanical factors in labour?
Power
Passage
Passenger
Generally how often should the contractions occur in established labour?
They should last 45-60 seconds and occur every 2-3 minutes
In which people may poor uterine activity occur?
- Nulliparrous women
- Induced labours
What are the 3 planes of the pelvis? Which diameters are largest?
Pelvic inlet- Transverse diameter
Midcavity- T and AP diameter same
Pelvic outlet- AP diameter largest
In the midcavity of the pelvis, what anatomical landmark is used to denote the station of a fetus?
Ischial spines:
- O: head at level of spines
- +2: head 2cm below spines
- -2: head 2cm above spines
What factors determine how easily the head fits through the pelvis?
- Attitude
- Position
- Fetal head size
What is the optimal presentation and position of a child for delivery?
- Cephalic, vertex presentation, occipito anterior
What is the difference between the presentation and presenting part?
Presentation is the part of the fetus which occupies the lower segment of the uterus- ie cephalic or breech
Presenting part- part of fetus which is palpable on vaginal examination
Definitions and optimal positions
Attitude
Position
Attitude- degree of flexion of the head. Optimal is vertex position
Position- degree of rotation of head on neck. Optimal is occipito anterior (allows smallest AP diameter for pelvic outlet)
What is the role of prostalglandins during labour, and which are most important?
They cause uterine contraction
Cervical softening, effacement, and dilation
F & E prostoglandins most important
What is the role of oxytocin during labour and pregnancy, and when is mostly produced?
Pulsatile hormone secreted from posterior pituitary, increased from 3rd trimester
Causes uterine contractions
Milk ejection reflex
When is labour diagnosed?
When contractions painful and regular- should last for 30 seconds to 1 min and occur every 3-4 minutes, along with effacement and dilation of the cervix
What is a false labour?
Irregular painful contractions without effacement or dilation of the cervix
Braxton hicks contractions occur throughout pregnancy but these aren’t painful
what is cervix dilation in first two stages of labour?
How long should they last for?
Latent phase- cervical dilation 3cm- lasts 6 hours to 2/3 days
Active phase- cervical dilation 4cm-10cm- lasts 12-16 hours
What is the minimum amount of dilation which occurs in first stage of labour?
1cm/hour
2cm/hour- in multiparrous women
What is the second stage of labour?
What are two phases?
From full dilation to delivery of the fetus
Passive stage- engagement, descent, rotation
Active stage- pushing
Delivery
What are the cardinal movements of the fetus in labour?
- Engagement- enters the pelvis
- Descent
- Flexion- midcavity
- Internal rotation to OA position in midcavity
- Further descent and pernieum distends
- Extension of the head and delivery
- Restitution/ external rotation to OT position. Anterior shoulder and posterior shoulder delivered with lateral body flexion
What is the third stage of labour?
From delivery of the fetus to the placenta
What is considered a prolonged 1st active stage of labour?
> 12-16 hours, and the cervix is not fully dilated
What is considered a prolonged second active stage of labour (clue different for multiparrous and nulli)
Nulliparrous women: >2 hours of pushing
Multiparrous women: >1 hour of pushing
What is a delayed 3rd stage of labour?
> 30 minutes- retained placenta
>60 minutes: continued bleeding or not removed then surgical removal under GA
State which structures are damaged on 1st, 2nd, 3rd and 4th degree perineal tear?
1st- Fuorechette
2nd- perineal muscle (episitomy)
3rd- anal sphicter
4th- anal mucosa
What is a partogram, and what is measured?
Partogram monitors progress in labour
- measures cervical dilation
- descent of head
- Maternal vital signs
- FHR
- Liqor colour (meconium stained indicate fetal distress)
What are the alert and action lines on the partogram?
- Alert line at 4cm dilation, if cervical dilation or descent cross line then refer to hopsital
- Action line- ahead to the right at 4 hours- hospital based decision
What is the most common cause of slow progress in labour?
Ineffcient uterine contractions
What are the associations with hypertonic contractions, and what is management?
How is it managed?
Placental abruption
Excessive oxytocin
Prostaglandin adminsteration during induction
If no placental abruption then give Tocolytics ie Terbutaline/salbutamol or C-section if there is fetal distress
What are the causes of a hypotonic uterus?
Induction
Nulliparrous labour
What is the management of a hypotonic uterus in the:
1st stage
2nd stage
1st stage:
Amniotomy- if doesnt work within two hours then
IV oxytocin- should work in four hours
C-section if not fully dilated within 12-16 hours
Passive 2nd stage- if poor descent then IV oxytocin
Active 2nd stage- ventouse or forceps
What is the most likely cause of failure to progress in labour in multiparrous women?
Passenger problems- atttitude or flexion ie disorders of rotation
What are the two disorders of position which may cause prolonged labour?
Occipito posterior
Occipto transverse
What is occipto posterior associated with and how is it managed?
Associated with prolonged labour and birth trauma, also associated with backpain and early desire to push
If not prolonged then may spontaneously rotate to OA or deliver OP
If prolonged 1st stage- amniotomy- IV oxytocin- C-section
If prolonged second active stage- then rotation with ventous or Kellands forceps
What are the disorders of flexion?
Brow presentation- imcomplete flexion
Face presentation- extension
How is brow presentation managed, and what is felt on vaginal examination?
Managed with C-section
Anterior fontanelle, nose, supraobrital ridge felt
how is face presentation managed, and what is felt on vaginal examination
(clue depends on anteiror chin)
Mouth, nose and eyes felt vaginally
delivered vaginally
if chin posterior then delivered with extension over perineum
if chin anterior then delivered with flexion over perineum
What two conditions may affect the size of the presenting part and cause prolonged labour?
Hydrocephalus
Breech presentation
What are some causes of prolonged labour which related to passage
Cephalopelvic disproportion- big baby, short women- retroscopective diagnosis
Pelvic variations
Abnormalities of pelvic architecture- ie osteomalacia, rickets, kyphosis, scoilosis
Pelvic massess- prevent engagement and descent- ovarian mass, uterine fibroids
What are some examples of pelvic variations causing prolonged labours?
Android pelvis- heart shaped
Platypelloid pelvis - oval shaped
Anthropoid pelvis- AP diameter greater than transverse at pelvic inlet
What are the maternal consequences of failure to progress in labour?
Dehydation- ketoacidosis- intrauterine infections- perineal tears- PPH
What are the fetal concequences of failure to progress in labour?
Fetal hypoxia- fetal acidaemia- cerebral palsy- intracranial haemorrhage- fetal pneumonia
When do you only do augmentation?
Don’t do in it in the latent stage, because augment when cervix is wholly effaced 2cm dilated and soft
In which patients is CTG indicated for during labour?
High risk
Meconium
Fever >37.5 degrees
What does a vaginal examination look at during labour?
Descent/engagement
Cervical effacement/dilation
Membranes if ruptured or not
Fetal presenting part
How often should a vaginal examination, maternal obs and FHR be conducted in the first stage of labour?
Vaginal examination and maternal obs- every 4 hours
FHR- every 15 minutes
How often should a vaginal examination, maternal obs and FHR be conducted in the second stage of labour?
Vaginal examination, maternal obs- 15 mins
FHR- with every contraction
During the second stage of labour if women have an epidural analgesia how long should they wait before they push?
An hour
How is fetal distress managed during the second stage of labour if there has been augmentation?
- Stop Iv oxytocin
- Left lateral position
- Iv fluids
- If abnormal FHR persists then Fetab blood scalp sampling
- pH 7.2 then C-section
During normal labour what is given in the third stage of labour?
10 IU of syntoconin or syntometrine (not to hypertensive patients)
When is induction indicated?
- Prolonged pregnancy >41/42 weeks
- term pre-labour rupture of membranes
- Fetal in utero death
- Gestational diabetes, macrosomia, pre-eclampsia
What is the Bishop score and what are the components of it?
Score which indicates the favourability of the cervix to induction ie if induction is likely to be successful <6 indicates no
- Cervical position
- Station
- degree of effacement
- Consistency
Induction protocol, and what monitoring do you need to do?
- Prostaglandins- vaginal or pessary
- Amniotomy
- IV oxytocin
If oxytocin or amniotomy then CTG for min of an hour
What are the complications of induction
- Hypotonic uterus- prolonged labour, PPH
- Hypertonic uterus- with prostaglandins or excesssive oxytocin- uterine rupture
- Increase C-section and instrumental risk
- Postpartum or intrapartum infecton
- Umbilical cord at prolapse
When is natural induction carried out?
Cervical sweep when >40 weeks
What is the definition of fetal lie?
Relationship of the fetus to the long axis of the uterus
What are the three types of abnormal lie/malpresetation, which two cant be felt at the pelvic inlet?
Longitudinal- cephalic or breech
Below two cant be felt at pelvic inlet:
- Oblique lie- felt in iliac fossa
- transverse lie- head in flank- causes shoulder presentation
Aetiology of abnormal lie?
Clue anything which allows extra rotation or doesnt allow rotation
- Too much room: Pre-term labour (not rotated), lax uterus due to increased parity
- Too little room: Polyhydroamnios, multiple pregnancy, placenta praveiae, submucous fibroids, pelvic mass
- Abnormal baby
What are the complications of abnormal lie?
Obstructed labour- uterine rupture
Shoulder presentation or cord prolapse
What is the management of malpresentation >37 weeks
- Admit to hopsital to monitor if ROM, and ultrasound to exclude praeviae and polyhydroamnios
- If spontaneous rotation and remains for 48 hours then discharge. Otherwise dont do ECV because baby will rotate again
- At 41 weeks either C-section, or ECV- and then amniotomy
What are the different types of breech presentations?
Extended- frank breech- most common
Flexed breech- complete breech
Footling breech
What is the aetiology of breech presentations?
Idiopathic
Pre-term labours
Conditions which prevent movement of fetus- fibroids, polyhydroamnios, ovarian masses
Conditions which prevent engagement- placenta praeviae, pelvic masses, and pelvic tumours
When should breech presentations be an issue?
From >37 weeks onwards
How do you diagnose breech presentations? (eg on examination findings)
On abdo exam: ballotable head at fundus- which causes upper abdominal pain
Confirm with transabdominal ultrasound
What are the complications of having a breech presentation?
- Increased risk of fetal abnormalities- ie fetal handicap
- CORD PROLAPSE
- Head gets stuck- cessation of labour- perinatal mortality
How is breech presentation managed?
At term >37 weeks: do ECV
Or planned C-section
With breech presentations when is ECV contraindicated?
If placenta praveia, if membranes ruptured (ie malpresentation do ECV then amniotomy), APH and vaginal birth contraindicated
When is normal meconium passed by?
24- 48 hours
What is the management of mecononium stained liquor?
- CTG - if fetal distress- then fetal blood sampling- <7.2– C-section
What is the complication of fetus passing meconium in utero?
meconium aspiration syndrome which causes severe pneumonitis, pulmonary oedema, surfactant dysfunction, pulmonary vasoconstriction and bronchoconstriction
What are prolonged ROM, or premature rupture of membranes at term?
ROM for >24 hours before onset of established labour
What are the complications of PROM?
- Maternal and neonatal infection
- umbilical cord prolapse
What is the management of PROM?
Induction via Prostoglandin E2 eg cervadil (slow release vaginal pessary)
Only broad spectrum IV antibiotics if mother has signs of infection
Monitor fetus for 12 hours following delivery (greatest risk period)
What is obstructed labour associated with?
When is it suspected?
Shoulder presentation, and cephalo-pelvic disproportion
Patient will become exhausted, dehydrated (dark urine, dry lips), tachycardic and shock
In a multiparrous women in obstructed labour what is Bandals ring and why does it occur?
Occurs because upper uterine segment becomes thicker and then lower uterine segment becomes stretched out
Ring forms between two junctions
What type of prostalglandin in Misoprostol and when is it used?
Which types of prostaglandin used in the induction of labour?
Misoprostol is E1- used in miscarriage abortion and in utero death in 2nd trimester
E2- eg cervadil which is slow releasing vaginal pessary
