Flashcards in Week 4 part 1 Deck (90)
a physiological process during which the fetus, membranes, umbilical cord and placenta are expelled from the uterus.
During labour: what keeps uterus settled, prevents formation of gap junctions and hinders contractibility of myocytes?
What hormone makes uterus contract?
Estrogen - also promotes prostaglandin production
What hormone initiates and sustains contractions?
Oxtytocin. Oxytocin acts on decidual tissue to promote prostaglandin release
Oxytocin is synthesized directly in decidual and extraembryonic fetal tissues and in the placenta
The number of oxytocin receptors increases in myometrial and decidual tissues near the end of pregnancy
What factors might initiate labour?
1. Change in estrogen/progesteroine ration
2. Fetal adrenals and pituitary hormones
3. Myometrial stretch
4. Mechanical stretch of cervix and stripping of fetal membranes
5. Ferguson reflex
6. Pulmonary surfactant secreted into amniotic fluid has been reported to stimulate prostaglandin synthesis
7. Increase in production of fetal cortisol stimulates an increase in maternal estriol
8. Increase in myometrial oxytocin receptors and their activation results in phospholipase C activity and subsequent increase in cytosolitic calcium and uterine contractility
In relation to stages of labour how much is cervix dilated in latent phase (phase after first stage)?
In relation to stages of labour how much is cervix dilated in active stage (stage after latent phase)?
4cm - 10cm (full dilatation)
During what stage of labour are there mild irregular contractions, cervix shortens and softens and duration variable?
In what phase of labour do contractions become progressively more rhythmic and stronger?
What stage involves complete dilatation of cervix 10cm to delivery of baby?
During the second stage of labour in nulliparous women - when is it considered prolonged?
If exceeds 3 hours with regional analgesia or 2 hours without
During the second stage of labout in multiparous women - when is it considered to be prolonged?
Exceeds 2 hours with regional analgesia or 1 hour wthout
What stage of labour involves devliery of baby to expulsion of placenta and fetal membranes?
Third stage (average duration 10 minutes)
If third stage has been after 1 hour what is prepared?
Removal under GA
How is the third stage of labour actively managed?
Use of oxytocic drugs and controlled cord traction - reduces risk of post partum haemorrhage
What is administered in active management of third stage labour?
1. Prophylactic syntometerine ... 1ml ampoule containing 500mg ergometrine maleate and 5IU oxytocin or
2. Oxytocin 10 units
What practically is done for active management of third stage labour?
Cord clamping and cutting,
Controlled cord traction
What is this phenomenon called in labour; Increase in hyaluronic acid gives increase in molecules among collagen fibres.
The decrease in bridging among collagen fibres gives decrease in firmness of cervix.
What is this phenomenon called in labour: decrease in collagen fibre alignment, decrease in collagen fibre strength, decrease in tensile strength of cervical matrix, increase in cervical decorin?
Cervical ripening, effacement or thinning
What is the name for tightening of uterine muscles, thought to aid body for birth, can start 6 weeks into pregnancy but usually felt in second or third trimester?
Braxton Hicks contractions
What is the feeling of a true labour contractions like?
The feeling of a true contraction has been described as a wave. The pain starts low, rises until it peaks, and finally ebbs away. If you touch the mother’s abdomen, it will feel hard during a contraction. Start about 5 minutes apart
Say three things about braxton hicks contractions?
1. Irregular, do not increase in frequency or intensity
2. Resolve with ambulation or change in activity
3. Relatively painless
What happens when body releases hormone called oxytocin, which stimulates uterus to contact?
Real Labour Contractions - tighten at top part of uterus pushing baby downwards - also promotes thinning of cervix
What region acts as pacemaker for contractions?
Tubal ostia - contractions have polarity (upper segment contracts and retracts, lower segment cervix stretch, dilate and relax)
What sort of contractions have fundal dominance with a regular pattern and an adequate resting tone?
When are contractions maximum?
How many in 10 minutes?
3-4 every 10 mins
10-15 seconds, max 45
What is an anthropoid pelvis?
Oval shaped inlet with large anterior posterior diameter and smaller transverse diameter
What pelvis is most suitable for females?
What pelvis has triagular or heart shaped inlet and is narrower from the front . Most common in african-caribbean women?