Normal Labour Flashcards
What is labour?
The process via which the foetus, placenta and membranes are expelled via the birth canal
What are some of the defining characteristics of normal labour?
- Occurs spontaneously (not induced)
- Occurs at 37-42 weeks gestation
- Fetus presents by the vertex (head down)
- Results in a spontaneous vaginal birth
What are some of the cervical and uterine changes that occur as labour initiates?
Cervix softens
Myometrial tone of the uterus changes to allow for coordinated contractions
What are some of the hormonal changes that occur at the initiation of labour?
- Progesterone decreases
- Oxytocin and prostaglandins increase
How many stages of labour are there? What does each stage encompass?
First stage - early / latent phase, active first stage and transition
Second stage - passive and active second stage
Third stage - active / physiological stage
What is the longest phase of labour that the woman will encounter? What characterizes this stage?
The latent phase of the first stage - can be up to days in length
Irregular contractions start, they are quite short lasting.
There is also shortening, thinning, anterior movement and dilatation up to 4cm of the cervix
What characterizes the active first stage of labour? How long does this stage last?
- Cervix dilating from 4cm to 10cm
- Regular, painful contractions (3-4 contractions per 10 minutes, all lasting about a minute)
Stage lasts about 8-12 hours
What characterizes the transition phase of the first stage of labour?
Cervix dilated 8-10cm
Physical changes:
- Patient may start to shake
- Feel the urge to vomit / empty bowels
- Express need for pain relief / feels she can’t cope
What characterizes the passive phase of the second stage of labour?
- Being fully dilated to the birth of the baby
- Involuntary expulsive contractions yet to start
What characterizes the active phase of the second stage of labour?
- Expulsive contractions begin / maternal effort to expel the baby
- May see partial presentation of the baby
How long does the second stage of labour last?
Usually 2-3 hours
What is an important factor that can affect the length of each of the first two stages of labour?
Whether the woman is nulliparous or multiparous
Nulliparous - never given birth before, or only to a stillborn baby
Multiparous - has given birth before
What characterizes the third stage of labour?
Includes birth of the baby and the expulsion of the placenta and membranes
What are the two options for managing the third stages of labour?
Physiological management: no drugs, clamping and placenta delivered by maternal effort
Active management:
- Uterotonic drugs
- Cord clamping
- Expulsion of placenta by cord traction
How long does the third stage of labour last?
Actively managed - completed within 30 minutes
Physiologically managed - within 60 minutes
How does contraction and retraction of the uterine wall facilitate delivery?
Creates a smaller volume in the uterus, increased pressure pushes baby out
Reduces diameter of the uterus to direct the baby through the pelvis
In which direction does the baby rotate during delivery? What causes this rotation?
Rotates internally
Resistance from the diaphragm along with the shape of the pelvis causes this rotation, moving the baby into a more optimal position for childbirth
When does crowning occur during childbirth?
When the occiput (back of head) slips below the pubic arch and the head no longer recedes backwards
(when you can see the top of the baby’s head)
What are the extension and restitution mechanisms of labour?
Extension - baby’s full head past the pubic arch, see the brow face and chin born over perineum
Restitution - baby’s head rotates to put it back in plane with rest of body
List the mechanisms of labour in order
- Engagement and descent
- Flexion
- Internal rotation of head
- Crowning and extension of head
- Restitution
- Internal and external rotation of head
- Lateral flexion of shoulders
What are the different types of fetal lie?
Cephalic / vertex - head towards pelvis, vertical
Breech - Buttocks towards pelvis, vertical
Transverse lie - horizontal lie of baby within uterus
What are the different types of fetal presentation?
Face presentation - Face of baby facing the vaginal opening
Brow presentation - Crown of baby’s head facing vagina
Shoulder presentation - Shoulder of baby facing the pelvic opening
What are the different fetal positions?
- Left occipital transverse / anterior / posterior
- Right occipital transverse / anterior / posterior
What is used to perform intermittent auscultation of the fetus’ heart rate? When is this done?
Pinards stethoscope or Hand held Doppler
Every 15 minutes for a full minute following a contraction in first stage of labour, every 5 minutes or after every contraction in second stage
Advantage of a hand held doppler over a pinards stethoscope?
Hand held doppler amplifies fetal heart rate so everyone in the room can hear it, only midwife can hear it with the Pinards stethoscope
What is the normal fetal heart rate?
110-160 bpm
Lots of variability (>5 bpm)
Often have accelerations of around 15bpm
What are some methods of monitoring maternal health during labour?
Maternal Observations - HR, BP, Temp etc.
Abdominal palpation - position of the baby
Vaginal examination - is mother dilated & position of baby
Monitoring of amniotic fluid (amniotic liquor) - colour / content
Palpation of contractions - palpate contractions for a 10 minute period every half hour, strength and tone
External signs - eg. Rhomboid of Michaelis and anal cleft line
What are some methods of supporting the mother through labour?
Maternal mobility and position - upright position and maintenance of mobility reduces pain
Breathing, hyponobirthing techniques, massaging, aromatherapy
TENS machines - encourages endorphin production & reduce pain signals
Oral analgesia
Pools / baths - water helps during first 2 stages
Entonox / opioids
Remifentanil PCA (patient controlled analgesia) / Epidurals
