Parturition And Labour Flashcards
Define parturition
The scientific term used to describe the transition from the pregnant state to the non-pregnant state at the end of gestation
Define labour
The non-scientific term used to describe parturition when both the cervix and uterus have been remodelled
What is a spontaneous abortion?
If the products of conception are expelled before 24 weeks
Define pre term
< 36 weeks
Define term in weeks
37 - 42 weeks
Define post term
> 42 weeks
What is the biggest cause of mortality mortality in the UK?
Going past 42 + 6
Carries lots of risks
Briefly describe what occurs in the first stage of labour
Creation of the birth canal
Briefly describe what happens in the second stage of labour
Expulsion of foetus
Briefly describe what happens in the third stage of labour
Expulsion of placenta
Contraction of uterus
When does the uterus become palpable?
12 weeks
Where is the fundus palpable at 20 weeks?
Umbilicus
Where is the fundus palpable at 36 weeks?
Xiphisternum
When does the foetus orientate itself correctly for birth?
24 weeks
Why do we weight the placenta?
Should be around the same weight as the foetus
Too large, too small or calcification - indications that the baby may need extra care
What is the ‘lie’ of the foetus?
Relationship to the long axis of the uterus
Normally longitudinal
Foetal spine antiparallel to mothers
What is the ‘presentation’ of the foetus?
Which part is adjacent to the pelvic inlet
Normally the head (cephalic)
What is the ‘vertex’ of the foetus?
Relationship of foetus along its axis
Head 45 degrees to own spinal cord
Orientation of the presenting part
What is the most common description of a presenting foetus?
Longitudinal lie
Cephalic presentation
Vertex to pelvic inlet at minimum diameter
What is the average diameter of the foetal head?
9.5 cm
What proteins usually expand the soft tissues of the pelvis?
Metalloproteases (type of collagenase)
What is effacement?
The internal and external Os come together (of the cervix)
What is the medical term for softening of the cervix?
Cervical ripening
Which prostaglandins are most responsible for cervical softening?
PGE2
PGF2 alpha
Why does hyaluronic acid build up in cervical softening?
Hydrophilic
Water moves into tissues causing expansion
What are Braxton Hicks?
Amplitude of contractions increases
Less frequent than ‘real contractions’
Uterus getting ready for labour
Define clinical labour
3 contractions within 10 minutes, each lasting at least 1 minute
Which hormonal ratio changes PG synthesis?
Oestrogen:progesterone
Increased oestrogen = increase PGs
Decreased progesterone = increase PGs
Where is oxytocin secreted?
Posterior pituitary
What do we call the reflex that increases oxytocin release?
Ferguson reflex
What are the effects of increased prostaglandins?
Cervix ripens
Contractions more forceful
Brachystasis
What is brachystasis?
Uterus contracts more than relaxes
Fibres shorten in body of uterus
Drives presenting part into cervix
When does the first stage of labour end?
When the cervix is dilated to 10 cm
Second stage of labour is usually how long?
Up to an hour
What do we call it if the foot presents first?
Footling breech
How long does 3rd stage of labour usually last?
Within 10 minutes
What are some stimuli that cause baby to take its first breath?
Trauma
Cold
Light
Noise
What are the major goals of uterine contractions?
Dilate cervix
Push foetus through birth canal
What are the 3 Ps of labour?
Powers
Passenger
Passage
How does the foetus contribute to labour?
Glucocorticoids released to inhibit progesterone
Foetal oxytocin produced
How do we induce labour?
Give prostaglandins directly into vagina
What does the ‘attitude’ of the foetus refer to?
Flexion or extension of the foetal head
What is the difference between frank and full breech?
Frank = knees extended Full = knees flexed
Why is cord prolapse a problem?
Cools down as comes out of cervix
Arteries spasm
Stops oxygen to the baby therefore indication for C section
What is the latent phase of labour?
1st part of 1st stage
Onset of labour with slow cervical dilation up to 4cm
Variable duration
What is the active phase of labour?
2nd part of 1st stage
Faster rate of cervical change
1 - 1.2 cm per hour
Regular uterine contractions
What are some of the biggest causes of maternal mortality?
Pre-eclampsia/eclampsia
Post partum haemorrhage
Obstructed labour
Unsafe abortion
What incision do we use for C section?
Pfannenstiel
When would we take a mum to labour AFTER the delivery of the baby?
If placenta hasn’t delivered within an hour after brith
3rd stage of labour not complete
Risk of infections and heavy bleeding
What is the normal blood flow to the placenta?
500 - 800 ml/min
How does the body control bleeding post delivery?
Powerful contractions/retraction of uterus
Pressure exerted on placental site by walls of uterus
Blood clotting mechanism - pregnancy is pro-thrombotic
