1st Stage of Labour - Epidural & Spinal (W/S 6) Flashcards
What changes occur to the uterus during pregnancy?
- Uterus grows from 60g to 1000g
- The lower segment formed at 32 weeks (due to increased stretching of uterine muscle fibres)
What starts labour?
- Less progesterone released by placenta
- Increase in oestrogen:progesterone ratio
- Oestrogens increase the production of prostaglandins
(F2alpha) - Oestrogens increase the contractability of the
myometrium - Oxytocin triggers are not completely understood but
pressure on the cervix causes release - ?some release from the fetus?
What is the definition of the first stage of labour?
From the onset of regular purposeful contractions (which cause cervical changes) until full dilatation of the cervix.
What does TENS stand for?
Trans electrical nerve stimulation
What does a TENS machine do?
Applies electrical current through the skin for pain control. It activates of opioid receptors in the central nervous system.
What is the latent phase of labour?
1st stage - Up to 4cm dilatation of the cervix
What is the active phase of labour?
1st stage - From 4cm to full dilatation of the cervix
What is effacement?
Effacement is the thinning/shortening and softening of the cervix.
What gets recorded on the partogram and how frequently?
FHR - 15-30 mins during 1st stage, 5 mins during 2nd stage (+ maternal pulse)
Blood pressure and temperature - every 4hrs
Contractions: length and frequency - every 30 mins
Cervical dilatation and descent of presenting part - every 4hrs
Amniotic fluid - every 4hrs
Describe the action and alert lines
The Alert line starts at 4 cm of cervical dilatation and it travels diagonally upwards to the point of expected full dilatation (10 cm) at the rate of 1 cm per hour. The Action line is parallel to the Alert line, and 4 hours to the right of / after the Alert line.
Describe the uterine muscles.
3 layers of muscle tissue.
Outer longitudinal muscle layer.
Middle oblique/spiral muscle layer.
Inner circular muscle layer.
The muscle layers are entwined between connective tissue of blood vessels, elastic fibres, and collagen fibres.
During labour, what happens to the joints and ligaments of the pelvis?
Joints widen and ligaments soften.
Explain contraction and retraction of the uterus.
Contraction is the tightening of uterine muscles fibres.
The uterine muscle fibres remain shortened after contracting during labour (i.e. retraction). This results in a gradual progression of the fetus downwards through the pelvis. The top of the uterus becomes thicker and pulls up the dilating cervix over the presenting part
What does CTG stand for?
Cardiotocograph
What does a CTG measure?
A CTG measures fetal heart and monitors uterine contractions.
What is a retraction ring?
A pathologic retraction ring (Bandl’s ring) of the uterus is a constriction located at the junction of the thinned lower uterine segment and the thick retracted upper uterine segment that is associated with obstructed labor.
Usually involves syntocinon. Primps or multips with syntocinon.
During the late first stage and early second stage, where is the pain most intense / highest level of intensity?
Uterine pain most intense
During the late second stage, where is the pain most intense / highest level of intensity?
Perineal pain the most intense
Describe first stage pain i.e. where it originates from and how it may be felt.
Originates from dilatation of the cervix, distension and stretching of the lower third of the uterus.
May be felt as referred pain in the abdomen, lower
back and rectum.
Describe second stage pain i.e. where it originates from and how it may be felt.
There is less stimulation from the dilated cervix and increased pressure on receptors in the stretching tissues of the pelvic peritoneum, uterine ligaments,
bladder, urethra and rectum.
Pressure on lumbosacral nerve plexus with descent
of presenting part causes referred pain in the back, thighs and legs.
What is the dose and route for morphine?
10mg IM
What type of medication is morphine?
Opioid analgesic
How long does it take morphine to work and how long does it last?
15 mins to work.
Lasts up to 4 hours.
Morphine shouldn’t be given within how many hours of birth and why?
Should not be given within 4hrs of birth as it crosses the placenta and is a large dose for the fetus - could cause respiratory distress.
