Normal Labour I Flashcards
When is full term?
Between 37 and 42 weeks
Define normal labour.
Occurs between 37 and 42 weeks
Born spontaneously
In vertex position
Mother and baby in good condition
When in a pregnancy are the three trimesters?
1st: 1-12 weeks
2nd: 13-27 weeks
3rd: 28-40 weeks
How is the estimated due date calculated?
Add 9 months + 7 days onto the 1st day of the last menstrual period
When is the puerperium? What is its significance?
Up to 6 weeks after delivery
Its when the physiological changes that have occurred during pregnancy are reversed
List the stages of labour. When do they each start and finish?
Stage 1
- latent phase: 0-3cm dilation
- active phase: 3-7cm dilation
- transition phase: 7-10cm dilation
Stage 2
- from full dilation to birth of the baby
Stage 3
- from birth of baby to delivery of placenta
What happens in stage 1: latent phase of labour?
May have ‘show’ a plug of mucus and blood which falls away from cervix opening
Irregular contractions, every 5-10 mins
Cervix effaces and dilates 0-3cm
Should be able to continue normal activities
What is effacement?
Cervix becomes thinner, softer
What happens in stage 1: active phase of labour?
Regular contractions, every 3-5 mins
Cervix dilates from 3-7cm
What happens in stage 1: transition phase of labour?
Very intense contractions, every 0.5-2 mins
Also contractions can slow
Mother gets anxious, distressed
SROM: spontaneous rupture of membranes
Dilates 7-10cm
Approximately how long do the latent, active and transition phases last?
Latent: 8-12 hrs
Active: 3-5 hrs
Transition: 0.5-2hrs
A mother should come to hospital as soon as she feels contractions. True or false?
False
During latent phase, she should stay at home.
When SROM occurs, what colour should fluid be? What if it’s not?
Clear
If it’s cloudy or yellowy-green this could be meconium passed by the baby because its passed its due date or is distressed
How frequent and what is the duration of contractions in each phase of stage 1?
Latent:
- every 5-30 mins
- last 30 secs
Active:
- every 3-5 mins
- last 1 min
Transition:
- every 0.5-2 mins
- 60-90 secs
A pregnant woman (week 40) rings you saying that she’s just passed what looks like phlegm with blood in it.
Should you tell her to come in to hospital?
No, this is the ‘bloody show’ which is normal
It is a mucus plug that is in the entrance to the cervix
Passing it indicates the cervix is beginning to dilate
A pregnant woman rings you saying she’s been having what seem like contractions. She is in week 35. The contractions are not very painful and occur very irregularly. They don’t seem to be getting closer together.
Should you tell her to come in to hospital?
No
These are probably Braxton-Hicks contractions (false contractions)
They don’t lead to labour
They’re mild, irregular and don’t get more intense and frequent
A pregnant woman (week 42) rings you saying her waters have just broken but the liquid looks dark yellowy green.
Should you tell her to come in to hospital?
Yes.
The baby has passed meconium into the amniotic fluid, which means it could be distressed.
What happens in stage 2 of labour?
Pushing starts!
Mother is fully dilated
Baby navigates through pelvis
Head becomes visible
Baby does some ‘cardinal movements’
Before being born
What 3 things affect how well stage 2 of labour goes?
Describe them.
The 3 Ps
Power: how forceful the contractions are
Passenger: the fetus: size, position etc.
Passage: the route through the pelvis
What can you do if contractions aren’t strong enough?
Give oxytocin
One of the 3 P’s is passenger. What things about the fetus affect how easy stage 2 of labour is?
Size: of head
Attitude: is the baby flexed or deflexed? Better if the baby is flexed
Lie:
- longitudinal (ideal, baby’s spine is in line with mother’s
- transverse (perpendicular)
- oblique (at an angle)
Presentation:
- cephalic (head first, ideal)
- breech (bottom first)
- shoulder
Station:
- relationship between lowest point of presenting part and the ischial spines of mother’s pelvis
What is it called when the baby:
- presents head first
- presents shoulder first
- presents bottom first
- is lying with spine perpendicular to mother’s
- is lying with spine at an angle to mother’s
- is lying with spine aligned with mother’s?
- cephalic
- shoulder
- breech
- transverse
- oblique
- longitudinal
What is meant by vertex presentation?
When the baby is presenting cephalic (head first)
But with its head flexed, this is ideal
How can you tell what presentation the baby is?
Vaginal examination
Feel for the head, use the fontanel to guide you, should feel the posterior fontanel
How is fetal station described generally?
What about when:
- when mother starts to push
- when you first see baby’s head
On a scale from -3 to +3
0 = level of ischial spines, engagement
Mother pushes when baby is at +2
See head at +3
What is meant by engagement?
When the baby’s head is at 0 station
At the level of the ischial spines
During stage 2 the baby does some movements to help it be born. What are they and describe them.
Descent: baby moves into pelvic inlet, then further down where it ‘engages’
Flexion: chin presses against chest as head meets pelvic floor
Internal rotation: fetal shoulders rotate internally so widest part of shoulders are in line with widest part of pelvic inlet
Crowning
Extension: as baby moves further down, head extends as head is born
Restitution: head externally rotates
Expulsion: of anterior shoulder, posterior shoulder then rest of body
What happens in the 3rd stage of labour?Explain how it happens.
Delivery of the placenta
Uterus contracts, placenta separates from uterus wall
And is delivered
How’s the Bishop’s score calculated?
- Fetal station
- cervical effacement
- cervical dilation
- position of cervix (moves from post to ant)
- softness of cervix
How would you induce labour in:
- BS 0
- BS 3
- BS 8+
0 = prostaglandin
3 = can do membrane sweep, or prostaglandin
8+ = ARM
How would you check if someone has ruptured membranes?
Nitrocene paper, like a litmus paper
What are the problems associated with post-term pregnancy?
When is it considered post-term?
after 42 weeks
Meconium aspiration PPH Infection Macrosomia Shoulder dystocia Maternal birth injury due to above Peri-natal morbidity and mortality
What’s the agpar score? What’s in it?
Activity (muscle tone) Grimace (reflex irritability) Pulse Appearance Respiration
What does a CTG show you?
Fetal heart and contractions of the uterus
How do you interpret a CTG?
Dr C BraVADO
Dr: define risk C: contractions Bra: baseline rate V: variability A: accelerations D: decelerations O: overall impression
How would you comment on contractions from looking at a CTG?
No in 10 mins
(big square = 1 min)
How long they last
Intensity (by feeling uterus)
How would you comment on baseline rate from looking at a CTG?
What’s normal?
Average HR of baby within last 10 mins
Ignore accels or decels
Should be 110-150
What would count as fetal tachycardia?
Causes?
Baseline rate above 160
Fetal hypoxia Chorioamnionitis – if maternal fever also present Hyperthyroidism Fetal or maternal anaemia Fetal tachyarrhythmia
What would count as fetal bradycardia?
Causes?
Actions?
Baseline rate below 100 for 3 mins or more
Mild (100-120): late gestational age, OP position
Severe (80 or less): hypoxia caused by cord compression, prolapse, epidural or spinal, maternal seizures
If severe, deliver immediately
How would you comment on variability on a CTG?
What’s normal?
Variability of the baby’s heart rate
Should be 5-25bpm
Can be reassuring, non-reassuring or abnormal
Reassuring: 5-25bpm
Non-reassuring:
less than 5 for 30-50 mins
over 25 for 15-25 mins
Abnormal:
less than 5 for 50+ mins
over 25 for 25+ mins
What could cause reduced variability on a CTG?
Fetal sleeping (up to 40 mins)
Acidosis (due to hypoxia)
Drugs
Prematurity
How would you comment on accelerations on a CTG?
Accelerations are good
Acceleration of HR by 15 or more for 15s or more seconds
If they happen at same time as contraction that’s good
Absence of them doesn’t really mean anything
How would you comment on decelerations on a CTG?
Drop in HR of 15bpm for 15s or more
Early: happen at same time as contraction, normal, due to pressure on baby’s head during contraction = raised ICP
Variable: just happen randomly, worrying
Late: begin at peak of contraction and end after contraction ended, worrying
Prolonged: lasts more than 3 mins, very worrying
What should you do if you see late or prolonged decelerations?
Take a fetal blood sample and test pH for acidosis
Late decels could be sign of hypoxia
Consider emergency C section
