Physiology and Stages of Labour Flashcards
Describe stage 1 of labour.
Cervical dilatation occurs in preparation for passage of the fetus (becomes active at 4cm)
Describe stage 2 of labour.
Commences when dilatation achieves its full capacity (10cm)
Ends with the delivery of the baby
Describe stage 3 of labour.
Delivery of placenta and fetal membranes, normally lasts under 10 mins
How many contractions normally occur in 10 mins?
3-5
What is the attitude?
the degree of flexion/extension of fetal head
When is the fetal head optimally flexed?
smallest possible diameter arrives at the pelvic inlet
3 Ps?
power
passage
passenger
Which hormone keeps the uterus settled, and prevents formation of gap junctions?
progesterone
Which hormone makes the uterus contract, promoting prostaglandin production?
estrogen
What initiations and sustains contractions?
oxytocin
What ratio change initiates labour?
progesterone:oestrogen
What happens to fetal cortisol in labour?
increases
Active management of stage 3?
give prophylactic oxytocin
Why is the clinician’s hand used to control delivery?
prevents precipitous expulsion, which could cause intracranial haemorrhage
What should be done to the umbilical cord?
should be double clamped and cut
What should also be recorded at stage 3?
no of blood vessels of umbilical cord
What are Braxton Hicks contractions?
no true labour - can start as early as 6 weeks into pregnancy, not usually felt until 2nd/3rd trimester.
Are BH contractions regular?
no, and no not increase in frequency or intensity
How are true labour contractions described?
waves
What is released to cause true labour contractions
oxytocin
What happens to cervix as contractions occur?
thinning
What is the highest density area of the uterine muscle?
fundus
How is haemostasis achieved?
- tonic contraction (lattice pattern of uterine muscle strangulates blood vessels)
- thrombosis of torn vessel ends
- myo-tamponade opposition of anterior/posterior walls
Is pregnancy a hyper coagulable state?
yeah
What is puerperium?
period of repair and recovery
What may occur during the 6 weeks of puerpium?
Lochia - vaginal discharge containing blood, mucus and endometrial castings
When does the endometrium regenerate by?
end of a week (except placental site)
What initiates lactation?
placental expulsion
What happens to oestrogen, progesterone and prolactin?
oes and prog decrease, prolactin is maintained
