Normal Labour Flashcards
what are the 3 key factors during labour
POWER: uterine contaction
PASSAGE: maternal pelvis
PASSENGER: fetus
What hormone initiates + sustains contractions
oxytocin
what other roles does oxytocin have
acts on decidual tissue to promote prostaglandin release
what hormone makes the uterus contract
oestrogen
name the other function of oestrogen in labour
promotes prostaglandin production
what is the role of progesterone
Keeps the uterus settled
Prevents formation of gap junctions
Hinders contractibility of myocytes
What hormone changes cause the initiation of labour
progesterone withdrawal
Increase in oestrogen + prostaglandin action
what hormone from the placenta is likely involved in starting the changes leading to labour
CRH
Corticotrophin-releasing hormone
What is the Ferguson reflex
name given to neuroendocrine reflex that self-sustains the cycle of uterine contractions initiated by the pressure at the cervix/vaginal walls
what is the bishop score
method used to assess if it is safe to induce labour
Name the 5 components of the bishop score
position consistency effacement dilatations station in pelvis
Describe stage 1 of labour
Commences with onset of regular painful contractions
Latent phase - up to 3-4cms dilatation
Active phase - 4-10cms dilatation
Describe stage 2 of labour
Full dilatation achieved
Delivery of baby
Divided into pelvic/passive phase (head descends down pelvis)
Active phase (when the mother pushes)
describe stage 3 of labour
Expulsion of placenta and membranes after birth of baby
After what time is the decision made to remove the placenta under GA if it has not been delivered naturally
1 hour
What can be given to help the mother deliver the placenta
Oxytocic drugs- oxytocin 10 units OR syntometerine 1ml
Controlled cord traction, cord clamping + cutting, bladder emptying
what causes the cervix to soften in preparation for labour
increased hyaluronic acid
decreases bridging among collagen fibres - decreased firmness
what causes the cervix to ripen in preparation for labour
decrease in collagen fibre alignment/stretch/tensile strength
Increase in cervical decorin
What are Braxton hicks contractions
Tightening of the uterine muscles, thought to aid the body prepare for birth
Not usually felt until 2nd/3rd trimester
what are true labour contractions
pain described as a wave- starts low, rises until it peaks, and finally ebbs away
what will the mothers abdomen feel like during contraction
hard
where in the uterus do contractions start
fundus
what are Braxton Hicks contractions also called
false labour
features that differentiate Braxton hicks contractions from true contractions
irregular
do not increase in frequency or intensity
resolve eventually
relatively painless
features of true labour contractions
evenly spaced (e.g. 5 mins apart) Time between them gets shorter and shorter get more intense and painful promote thinning of the cervix don't resolve
what is the Ostia
distal tube opening of the infundibulum of uterine tube into abdominal cavity
where do contractions synchronise from
both Ostia
what shaped pelvis is most suitable for labour
gynaecoid pelvis
what are the other shapes of pelvis
anthropoid - oval shaped inlet
Android- triangle inlet (afro-carribean women)
Platypelloid
What is the function of amniotic fluid (liquor)
nurtures and protects the foetus
facilitates movement
what colour should liquor be
clear
Red/pink suggests bleeding
what is the normal fetal position
longitudinal lie
cephalic presentation
presenting part = vertex
Normal fetal position in labour
Occipitoanterior with head engaging occiptial-transverse
what are the major fontanelles in the fetal skull
anterior fontanelle (diamond shaped) posterior fontanelle
how do 95% of fetal heads appear in vertex presentation
flexed
What position does a flexed vertex baby go into
NORMAL
e.g. occipitoanterior
What position does an extended or deflexed vertex baby go into
ABNORMAL
e.g. occipitoposterior or transverse
how is the descent of the head referenced
abdominal 5ths
what is crowning
appearance of a large segment of head at the Introitus
Labia are stretched to full capacity
what may be required to prevent trauma to the anal sphincters during crowning
episiotomy
what are the analgesic options for Labour
Paracetemol /co-codamol TENS (electrical pulses) Entonox (inhalation agents) Diamorphine Epidural IV Remifentanyl Combines spinal/epidural
what is the risk with epidural
respiratory depression
what is a normal blood loss in labour
<500mls
what is an abnormal blood loss in labour
> 500mls
what is a significant blood loss in labour
> 1500mls
what are the signs that the placenta has separated
uterus contracts, hardens and rises
Umbilical cord lengthens permanently
gush of blood
How is haemostasis achieved after delivery
Tonic contaction of uterine muscle strangulates blood vessels
Thrombosis of the torn vessel ends- pregnancy is a hyper-coagulable state
What is puerperium
period of repair and recovery
Return of tissues to non-pregnant state in 6 weeks
What is lochia
vaginal discharge following delivery containing blood, mucus and endometrial castings
different types of lochia
rubra (fresh red)
Serosa (brownish-red, watery)
Alba (yellow)
what initiates lactation
placental expulsion
what is colostrum
name given to milk produced by mothers
what is colostrum rich in
immunoglobulins
