Labour, Delivery and Analgesia Flashcards
When does normal delivery occur?
Between 39-41 weeks since date of last menstrual period
Within 24 hours of onset of regular contractions
Describe the first stage of labour
The time between the onset of regular contractions, until the cervix is fully dilated
Latent phase is when the cervix is less than 4cm dilated, and not yet fulled effaced
Active phase is between 4-10cm dilated and cervix is fully effaced
What is effacement
The change in the shape of the cervix from ‘bulbed’ to flat
- balloon demonstration
Describe the second stage of labour
Between complete dilation of the cervix, and birth of the baby
- normally takes between 15-120 mins
Describe the third stage of labour
Delivery of the placenta and membranes
- control of bleeding
Describe the mechanisms of labour
Engagement (in the occipito-transverse position, the fetal head entered the pelvis)
Decent and flexion of the head as it aligns with the pelvic gutter
Internal rotation occurs as the gutter forces the fetal head to turn 45 degrees, so the baby is facing posteriorly
- shoulders remain occipito-transverse
Extension of the fetal neck occurs as the head passes under the symphysis pubis, and the head is delivered
Restitution (external rotation) occurs once the head is delivered (occipito-anterior), and realigns with the shoulders (occipito-transverse)
Expulsion is delivery of the shoulder and rest of the fetus
- anterior shoulder first, then posterior
How is labour diagnosed
Regular painful contractions in the presence of an effaced cervix (which is 3cm or more dilated)
Contractions are identified by palpation and identification on CTG
Clinical assessment of labour
Palpation of contractions - strength - timing - length CTG - only information regarding the timings of contractions, not strength Vaginal examination - bishop's score - dilatation - effacement
What is a partogram
Composite graphical record of key data (maternal and fetal) during labour
Components
1) patient ID
2) time, recorded at intervals of one hour
3) fetal heart rate (every 30 mins)
4) state of membranes and colour of liquid
5) cervical dilation and decent of head
6) uterine contractions (duration and intensity)
7) drugs and fluids
8) blood pressure every 2 hours
9) pulse rate every 30 mins
10) oxytocin
11) urine analysis
12) temperature
What are the components of a Bishop’s score
- used for cervical assessment
Cervical dilatation Length of cervix Station of presenting part Consistency Position
The higher the score, the more likely labour will begin without induction
Differences between a pregnant and non-pregnant uterus
Non-pregnant - 6-8cm long - 5cm wide - walls 2cm thick - 70g Pregnant - cellular hyperplasia and hypertrophy - 4-5 x enlarged - 1000g - accommodates 5 litres
Describe the balance of forces that keep the fetus in-utero until term, and the balance of forces that allow delivery of the infant at term
Fetus kept in-utero because - high cervical resistance - low muscular corpus expulsive forces Fetus delivery because - low cervical resistance - high muscular corpus expulsive force
Describe the differences between the uterine cervix and the uterine corpus
Uterine cervix - sparse contractile myocytes - high fibrous connective tissue (provides tensile strength) - type 1 and type 3 collagen Uterine corpus - parametrium - myometrium (muscle) - endometrium (ciliated columnar epithelium)
Describe the myometrium
Provides the tissue which allows the uterus to contract
- mainly myocytes
- also connective tissue, blood vessels, lymphatic vessels and nerves
What are the two main hormones that modulate contractile activity
Oxytocin
Prostaglandin
