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