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?
What nurtures and protects fetus and facilitates movement?
What is the normal feta position?
Longitudinal lie with cephalic presentation (head first), vertex presents, occipto anterior, flexed head
7 cardinal movements
4. Internal rotation
5. Crowning and extension
6. Restitution and external rotation (realign head with shoulders spontaneously)
7. Expulsion, anterior shoulder first
What is the term for appearance of large segment of fetal head at introitsu, labia stretched fully, burning and stinging feeling for mother?
What five factors are used for evaluating cervix?
5. Level of presenting part
What is Bishops score used for?
Cervix score. prelabour scoring system to assist in whether induction of labour is needed.
If cervix posterior what score does it get with Bishops?
What are these drugs used for: TENS, paracetamol, etonox, diamprhpine, epidural, remifentanyl?
Analgesia options in labour
How much blood loss is normal in labour?
Less than 500ml
In placental seperation what is the plane?
Spongy layer of decidua basalis
What are the three signs suggesting placental seperation? (usually 5-10 minutes after delivery)
1. Uterus contracts, hardens and rises
2. Umbilical corcd lenghtens permanently
3. Gush of blood variable in amount
How is haemostasis achieved in labour?
1. Tonic contraction
2. Thrombosis of torn vessel ends
In puerperium (period of repair and recovery) hjow long does it take for tissues to return to non-pregnant state?
When does diuresis commence in puerperium?
2-3 days postnatally
In puerperium what initiates lactation?
DR C BRAVADO is used to interpret CTG's. What does it stand for?
What is foetal tachycardia defined as?
Foetal tachycardia is defined as a baseline heart rate greater than 160 bpm. Normal is 110-150
What is foetal bradycardia defined as?
Foetal bradycardia is defined as a baseline heart rate less than 120 bpm.
What is normal variability of foetal heart rate?
Normal variability is between 10-25 bpm³
What are accelerations?
Accelerations are an abrupt increase in baseline heart rate of >15 bpm for >15 seconds.
What can CTG overall impression be described as?
What causes labour pain? two things
Compression of para-cervical nerves
What inhalation agents can be used for labour analgesia?
Entonox - gas and air
What analgesia for labout can be given IV?
a BENEFIT OF epidurals?
Does not impair uterine activity
Where are apidurals available?
Only in obstetric units
In epidurals what stage of labour can be longer?
5 complications of epidurals
1. Hypotension 20%
2. Dural puncture 1%
4. Back pain
5. Atonic bladder
What signs suggest suspected delay in stage 1 for nulliparous and parous women?
Nulliparous - less than 2cm dilation in 4 hours
Parous - less than 2cm in 4 hours or slowing in progress
Failure to progress - the three Ps?
Powers - inadequate contractions in frequency and strength
Passages - short stature/trauma/shape
Passenger - big baby, malposition
Diameter of vertex presentation, suboccipito-bregmatic?
Occipitofrontal presentation diamter?
Extended brow presentation measurement?
Graphic representation of progress of labour?
In relation to intra-partum fetal assessment: during stage 1 how often is US of fetal heart done?
During and after a contraction
In relation to intra-partum fetal assessment: during stage 2 how often is US of fetal heart done?
Every 5-10 minutes
Three parts of intra-partum assessment ?
US of fetal heart
Colour of amniotic fluit
If risk factors for fetal hypoxia what should be done?
Continous monitoring of fetal heart
What are these risk factors for?
Preterm / Post Dates
Hypertension / Pre-eclampsia
Sepsis (Temp > 38C)
Induction / Augmentation of labour
Name some acute causes of fetal distres?
1. Abruption - placenta comes away from inner wall
2. Vasa Praevia - blood vessels of fetus cross internal os
3. Cord prolapse
4. Uterine rupture - CS scar tears open
5. Feto-maternal haemorrhage
6. Uterine hyperstimulation
7. Regional anaesthesia
When should tocolysis be considered?
Managmenet of fetal distress - terbutaline 250 micrograms
In fetal blood sampling what is normal scalp Ph?
Greater than 7.25
If fetal blood sampling prodcues pH of 7.20-7.25 what should be done?
Repeat in 30 mins
If fetal blood sampling produces scalp Ph OF LESS THAN 7.20 WHat should be done?
Give two standard indications for operative vaginal delivery?
1. Delay - failure to pregress to stage 2
2. Fetal distress
What are special indications for operative vaginal delivery?
Maternal cardiac cisease
umbolical cord prolapse stage 2
What is ventouse associated with?
Increased failure, cephalohaematoma, retinal haemorrhage and maternal worry
Decreased anaesthesia, vaginal trauma and perineal pain
What rae these indications for; previous CS, fetal distress, failure to progress in labour, breech presentation, maternal request?
Caesaren section - 4x greater maternal mortality
When is dating USS organised for?
11-12 weeks (hospital)
When is anomaly scan done?
When is anti-D given?
28 weeks and 34 weeks
Define chronic (essential) hypertension in pregnancy?
HTN present at booking or less than 20 weeks
Define gestational hypertension
New HTN greater than 20 weeks without significant proteinuria
New hypertension greater than 20 weeks + significant proteinuria
What does hypertension in pregnancy do to renal system?
Decreased GFR, proteinuria, increased serum uric acid, increased creatinine/potassium/urea, oliguria/anuria, acute renal failure (acute tubular necrosis, renal cortical necrosis)
4 complications with the liver in hypertension in pregnancy?
1. Epigastric RUQ pain
2. Abnprmal liver enzymes
3. Hepatic capsule rupture
4. HELLP syndrome - haemolysis, elevated liver enzymes, low plateleys
During booking and antenatal care what management is done for HTN?
Risk factors for preeclampsia - then give aspirin, also monitor BP and urine
What medications must be stopped in hypertension in pregnancy?
ACE and ARBs
What are the three hypertensive medications used in pregnancy?
if severe then labetalol oral/IV, hydralazine IV or nifedipine oral
What BP should be aimed for in pregnancy with hypertension?
Less than 150/80-100
Effects of hypertensive dosirdwers include vasoconstriction