Labour and delivery Flashcards
Definition of labour
Progressive uterine contractions with progressive cervix dilation and formation of forewater
What is forewater and hindwater
Forewater - amniotic fluid below fetal head with tense membrane
Hindwater - amniotic fluid above fetus
Stages of labour
1: onset of labour to cervical dilation of 10cm
2: dilation to expulsion of fetus
3: expulsion of placenta
Parts of the pelvis that make the birth canal
Pelvic inlet
Mid cavity (ischial spines)
Pelvic outlet
What is the only fixed diameter of fetal head
9.5cm biparietal diameter
What is the smallest presenting diameter of the fetal head
9.5cm suboccipital to bregma diameter
Occipital anterior position
What is the presenting diameter in occipital posterior position
13.5cm suboccipital to brow
Therefore need C/S
Definition of position
Relationship of presenting part of fetus to quadrants of pelvic outlet
Definition of station
Relationship of biparietal diameter to ischial spines
-3 to +3
What station does internal rotation occur
0
Describe internal rotation
45 degree rotation
Occipit becomes anterior
Shoulders do not rotate
What is restitution
Head corrects itself to facing forwards once delivered
How are the shoulders delivered
After restitution the head externally rotates so the shoulders are in the AP plane of the pelvic outlet and can be delivered
What are the sub stages of stage 1 of labour
Latent: softening of cervix, effacement, shortening of cervix and dilation up to 4cm (up to 20 hours in nulliparous and 14 hours in multiparous)
Active: dilation of cervix at a minimum rate of 2cm every 4 hours
What are the sub stages of stage 2 of labour
Passive pushing: allow 1 hour for passive pushing for fetal head to descend. Only in women with an epidural.
Active pushing: expect head to deliver within 1 hour
Reasons for prolonged labour in first stage
Weak uterine contractions Slow effacement of cervix Occipitoposterior position Nill parity Large fetus Abnormal presentation Multiple pregnancy
Management of prolonged first stage labour
Oxytocin infusion
ARM if not already ruptured and bishops >7
Why is oxytocin used in caution with diabetes and asthma
Has ADH effect so can cause severe water retention
Side effects of oxytocin
Hyperstimulation of uterus and uterine rupture Headache Arrhythmia N+V Dyspnoea Hypotension
What drugs can be given to speed up 3rd stage of labour
Syntometrin
Syntocinon 10 units
Side effect of ergometrine
Headache
Nausea
Hypertension
What is measured in bishops score
Position of cervix Position of baby's head Consistency of cervix Effacement Dilation
What does bishops score mean
Higher the number /10 the more likely labour will progress without intervention
What bishop score means that labour is unlikely to progress
Below 6
What bishop score can you do an ARM for
Above 7
How do you induce a stillbirth
Give misoprostol
3 Ps of labour
Power
Passenger
Passage
How to assess power of labour
Observation
Manual palpation
CTG
What comes under passenger
Number of foetuses
Presentation - pole overlying maternal pelvic inlet (breech or cephalic)
Position - relation of presenting part of fetus to quadrants of maternal pelvis. Should be occipital anterior.
Station - relation of biparietal diameter to ischial spines
Lie - relation of fetus to long axis of uterus
What makes the pelvic inlet
Sacral promontory
Lines terminalis (pectineal line, arcuate line, pubic crest)
Pubic symphysis
What makes the pelvic outlet
Pubic arch
Ischial tuberosities
Sacrotuberous ligaments
Coccyx
What is prolonged 1st stage of labour
Active phase at least 2 hours longer than expected
I.e 4-10cm should take 1.2cm/hour (nulliparous) and 1.5cm/hour (multiparous)
Therefore over 7 hours or 6 hours respectively
What is prolonged 2nd stage of labour
Nulliparous: >3 hours with epidural or >2 hours
Multiparous: >2 hours with epidural or >1 hour
What is prolonged 3rd stage of labour
30 minutes
Risks of instrumental delivery
Cephalohaematoma
Temporary facial nerve paralysis (compression at stylomastoid foramen)
Bruising
Brachial plexus injuries
Contraindications for instrumental delivery
Any presentation other than cephalic <34 weeks Cervix not fully dilated Membranes not ruptured Bladder not emptied
Management of delayed 2nd stage
Oxytocin +/- epidural for analgesia
Instrumental delivery
Consider C/S
Assessment of newborn
Examine at 1,5,10 minutes after delivery APGAR: Appearance Pulse Grimace - reflex, irritability Activity Respiration
