What are the 3 major diagnostic features of labour?
- Regular contractions (at least one every 10 mins)- Cervical changes (effacement, dilatation) ± rupture of membranes
What is the latent phase of the first stage of labour?
- From onset of labour (hard to define) until cervix is 4cm dilated- Usually takes ±8 hours, but there is no set time limit
What is the active phase of the first stage of labour?
- From 4cm cervical dilatation until delivery- Cervical dilatation should occur at minimum 1cm/hour [1,5cm in multigravidae, 1,2cm in primigravidae]
What is the clinical importance if a patient crosses the “warning line” in the first stage of labour?
- Poor progress of stage 1 (i.e. dilating too slowly)- Patient MUST be examined- Reason for poor progress must be identified and addressed
What is the clinical importance if a patient crosses the “action” in the first stage of labour?
- Patient must be delivered ASAP- A doctor must evaluate the patient
When to suspect cephalopelvic disproportion?
- Head does not descend into pelvic inlet (>2/5 of head above pelvis) AND cervix is dilating
How to exclude cephalopelvic disproportion?
- 2/5 or less of head is palpable above the pubic bone
Which bones may overlap in moulding?
- Occipital-parietal- Parietal-parietal
Grades of moulding
0 Bones normally separated+ Bones touching each other++ Bones overlapping but may be separated with fingers+++ Bones overlapping and inseparable
Maternal monitoring in first stage of labour
- 4-hourly assessment: abdominal and vaginal examinations- 2-hourly assessment IF: >8cm; alert line crossed; evidence of maternal or fetal distress
Fetal monitoring in first stage of labour
- Every hour in latent phase- Every 30mins in active stage (level 1 patients)- Continuous CTG in all level 2 and 3 patients, or with meconium-stained liquor
Fetal monitoring in second stage of labour
- After every contraction- Can alternatively use CTG
Active management of third stage of labour
- Ensure there isn’t an undelivered twin still inside!2. Administer oxytocin (10 IU, given IM)3. Clamp and cut umbilical cord4. Controlled traction of the cord until placenta is delivered
At what gestational age will the head engage in a primi gravida?
36/52
What are the components of intrauterine resuscitation?
IV fluidsO2 for motherLeft lateral positionTocolyseMonitor fetus
Describe the two sources of powers in labour?
Uterine contractions - occur throughout pregnancy, coordinated in labour, 3 in ten minutes, bring about cervical dilatation and aid with descent of the fetus once fully dilated
Maternal explosive effort- bearing down = vasalva maneuvre
Describe the lower uterine segment
Lower pole of uterus and cervix that has less muscle, more fibrous CT
Does not contract and retract
Stretches, and stretches rapidly during labour
Begins to form at 28/40
What changes occur in the pelvis regarding passage and passenger?
Passage- ligaments become more lax
Has three components- elliptical I let and outlet, with round midcavity
Passenger must follow orientation to each area in order to descend
What are the four pelvic shapes?
Gynaecoid
Android
Anthropoid
Platypelloid
What are the 5 mechanisms of labour
Descent Flexion Internal rotation Extension External rotation
How does the fetus enter the inlet and why?
Enters looking sideways - occipito-transverse position
Because narrowest diameter of fetal head (BPD) matched to narrowest pelvic diameter (AP diameter)
What position does the fetal head assume during descent and why?
Assumes occiput transverse position
Widest pelvis diameter for the widest part of fetal head
Why is fetal head flexion important during descent?
Flexion creates smaller structure to pass through the maternal pelvis
What is internal rotation?
90 degree rotation in midcavity to a direct occipito-anterior or posterior position to exit elliptical outlet
