Lecture 16 - Labour And Birth Flashcards
What is parturition?
Labour
What is the definition of labour?
The process by which the fetus and its supporting placenta and membranes pass from the uterus to the outside world
What are the 3 key processes that occur during labour?
Regular high intensity conntractions
Softening and dilatiation of the cervix
Rupture of the Fetal membranes
What is considered a miscarriage?
Before 22 weeks
What is considered premature or pre term labour?
Before 37weels
What is considered term labour?
37weeks +
What are the 3 stages of labour?
1 = contractions and cervical dilatation (latent phase and active phase)
- Fetal descent and delivery (baby is born)
3 = placenta delivered
How wide does the cervix dilate to in the first stage of labour?
10cm
What general changes occur in stage one of pregnancy to create the birth canal?
Pelvic ligaments soften due to progesterone
Inc myometrium contractions
Cervical dilation and effacement (thinning)
What triggers cervical softening/ripening?
Prostaglandins
What occurs at the cellular level in cervical softening/ripening?
Less collagen and inc gylcosaminoglycans
Collagen bundles loosen (dec aggregation)
Influx of inflammatory cells and inc NO output
What happens to the myometrium in pregnancy?
Gets thicker (hypertrophy)
What sort of contractions of the myometrium occur in early pregnancy?
Small practice contractions of low amplitude
Brixton-Hicks contractions which are more noticeable but not painful
These contractions can’t effect cervix
How are prostaglandins important in myometrium contractions in labour?
Enhance release of calcium from Intracellular stores
What type of hormone is oxytocin?
Where is it secreted from?
Peptide hormone
Posterior pituitary gland (made in hypothalamus)
What is the function of oxytocin?
Lowered threshold for triggering action potentials/contractions in the myometrium.
What is the name reflex that is a positive feedback mechanism in labour?
Ferguson reflex
What is the Ferguson reflex?
Baby pushes head against cervix
This activates stretch receptors leading to posterior pituitary releasing oxytocin
Oxytocin stims smooth muscle uterine contractions to occur
Causes baby to push harder against cervix …..etc
What is brachystasis?
Where the muscle fibres dont fully relax after each contraction in labour slowly shortening the uterus helping force the baby out
What is the second stage of labour?
What occurs?
Where the baby is delivered
Cervix fully dilatated (10cm) until fetus is born
How long does the second stage of labour ((delivery) occur in:
Multiparous women?
Nulliparous (primigravida)?
Multiparous = 1hr
Nulliparous = 2hrs
What does primigravida mean?
First pregancy
What are the 7 movements that the baby does during the second stage of labour?
Engagement (go into pelvis)
Descent
Flexion (head/neck flexes)
Internal rotation (head faces backwards)
Extension (of neck, Crowning can see baby head)
External rotation
Expulsion
Go the last slide and label the 7 movements oof the baby during the second stage of labour:
1 = engagement
2 = descent
3 = Flexion
4 = internal rotation
5 = extension
6 = external rotation
7 = expulsion
What occurs in the 3rd stage of labour?
Fetus has just been delivered now the placenta and membranes need to be delivered
What is meant by a physiological third stage or active third stage of labour?
Physiological = no medication used, midwife waits for umbilicus to stop pulsating before cutting cord and delivery of placenta is passive
Active = Oxytocin given causing strong contraction of uterus cutting off blood supply to the placenta
Why is active third stage of labour normally always done?
Injection of oxytocin leads to strong contractions cutting of placental blood supply reducing risk of Post Partum Haemorrhage (PPH)
Why must the midwife check the placenta following its delivery?
Some could be in the uterus still which could lead to haemorrhage
Placental infarction can indicate pre-eclampsia
What is the score used to score how healthy a baby is once it’s been born?
APGAR score
Higher score = Healthier
What are the 3 Ps affecting labour?
Passage (birth canal)
Passenger (baby)
Powers (contraction)
What limits the size of the birth canal?
Diameter can’t extend beyond th limits of the pelvis
What is the most common shape of female bony pelvis?
Gynecoid
What is an adaption the fetus has to aid it during delivery?
Its head is soft/can mold to reduce diameter to aid with delivery
(The sutures haven’t fused)
What is the fetal lie?
The relation of the long axis of the fetus to that of the mother
What are the 3 main types of fetal lie?
Longitudinal lie (head to feet, feet to head)
Transverse lie
Oblique lie
What is meant by fetal presentation?
The leading part of the fetus or the anatomical structure closest to the to the maternal pelvic inlet
What is a cephalic presentation?
When baby is he’d first (normally with longitudinal lie)
What is a breech presentation?
Bum first
Frank breech = bum first feet in air
Footling breech = foot through first
Why are breech babies normally delivered via c section?
Risk of umbilical cord compression since baby starts delivery before cervix fully dilated
How can you determine fetal lie?
Obstetric abdominal exam
Vaginal exam
How does frequency a duration of contractions change as you go through the latent phase and active phase of 1st stage and then second stage?
Inc frequency and longer duration
What can be given to a mother if contractions are becoming less frequent and shorter?
Oxytocin
What is shoulder dystocia?
Vaginal cephalic delivery that requires additional obstetric maneuoveres to deliver the fetus due to anterior shoulders getting stuck on the pubic bone but the head has been delivered
Why is shoulder dystocia considered an obstetric emergency?
Head gets delivered and baby getting no oxygen
What increases the risk of shoulder dystocia before labour?
Previous shoulder dystocia
Macrosomia
DM
BMI > 30
Induced labour
What are some Intra Partum risks for shoulder dystocia?
Prolonged first stage of labour
Labour progressed then stopped
What complications can occur as a result of a shoulder dystocia?
Brachial plexu injury like Eros palsy
Neurological dysfunction/diasbility (lack of O2)
Neonatal mortality
PPH (post Partum haemorrhage)
Tears (trauma)
What are some intrapartum monitoring methods?
Doppler
CTG
Fetal scalp electrode
Fetal blood sampling (to check pH if acidic suffering with hypoxia)
What are some ways labour can be induced?
Prostaglandins (starts softening cervix)
IV oxytocin (stims contractions)
Artificial rupture of membranes (ARM)/amino hook
What are some indications for assisted delivery to take place?
Failure to progress
Maternal exhaustion
Maternal conditions (like heart disease)
Fetal compromise
What are some methods of assisted delivery?
Forceps
Suction cup/ventouse
What are some indications for a caesarean section?
Mail presentation (low fetal HR)
Macrosomia
Failure to progress
Fetal compromise
Fetal malformations
Previous
What is a pneumonic that can be used to remember the 7 movements of the baby during the second stage of labour?
Every Day Fine Infants Enter Eager and Excited
What does the pneumonic stand for which is used to remember the 7 cardinal movements of the baby during labour?
Every Day Fine Infants Enter Eager and Excited
Engagement
Descent
Flexion
Internal rotation
Extension
External rotation
Expulsion
