Normal Labour and Delivery Flashcards
What is labour?
Process by which regular, painful contractions bring about effacement and dilatation of the cervix and descent of the presenting part ultimately leading to expulsion of the fetus and the placenta of the mother.
How is labour initiated?
In the fetus: There is a rise in ACTH from anterior pituitary gland, rise in Angdrogens and glucocorticoids from the adrenal glands.
In the placenta: Progesterone levels drop and estrogen levels rise which are important for rise in prostaglandins.
In the mother: There is an increase in uterine sensitivity to stretching. Increase in uterine contractions. Increase in uterine sensitivity to oxytocin. Softening of the cervix.
What initiates the uterine contractions?
Rise in oestrogen leads to rise in prostaglandins which lead to increased uterine contractions, increased uterine sensitivity to oxytocin, and to softening of the cervix.
Labour initiates stretching of the cervix and the vagina which leads the posterior pituitary to increase contractions by producing oxytocin which creates a positive feedback loop leading.
What are pre labour irregular contractions called?
Braxton Hicks contractions
What happens during the prelabour period?
Myometrial excitement leading to braxton hicks contractions.
Descent of foetal head into the pelvis
Cervical ripening (Cervix becomes soft - collagen contractions are reduced and replaced by water content)
Show (Loss of blood-tinged mucoid plug within the cervix or the amniotic sac can rupture i.e water breaking)
What is cervical effacement?
Refers to gradual inclusion of cervix into the lower uterine segment
What is cervical dilatation?
The opening of the cervix from closed to full dilatation
What are the stages of labour?
3 stages:
1st stage: Between the time of onset of labour until the time of full cervix dilatation (10cm).
2nd stage: Full dilatation of the cervix until expulsion of the foetus from the birth canal. (Lasts 1 - 2 hours in nullipara and <1 hour in multipara usually)
3rd stage: Begins after delivery of baby and ends in expulsion of the placenta and membranes. (doesn’t usually last longer than 30 minutes)
What are the 2 parts of the first stage of labour?
Latent labour: Time between onset of labour to 4cm dilatation. This stage has no time frame and can take really long or can happen really quickly (average duration is 12 - 14 hours in a nullipara or 8 hours in a multipara)
Active labour: Describes the time from 4cm to 10cm dilatation. 1cm per hour
What is a nullipara vs multipara?
Nullipara: never given birth before
Multipara: given birth several times before.
What influences labour?
Passages (pelvis and pelvic floor)
Powers (Contractions and secondary powers of expulsion)
Passenger (Foetal presentation, attitude and foetal size/position)
Which direction is the pelvic inlet, the mid-cavity, and the pelvic outlet largest? What does this mean?
Inlet - ~13cm transverse
Mid-cavity - round 12 cm
Pelvic outlet - AP direction ~13cm
Head starts transversely rotates mid cavity and then goes to AP direction.
What guides foetal head movement in baby?
The pelvic floor muscles rotate and flex the presenting part of the foetus.
How are the uterine contractions coordinated?
The contractions start at the uterine fundus and sweep towards the lower segment drawing the lower segment up over the presenting part so the cervix effaces and dilates and the foetus descends into the pelvis.
What is fundal dominance?
The contraction starts and lasts longer in the fundus where it is also most intense.
What are the secondary powers of expulsion?
Pressure from presenting part on the pelvic floor stimulates nerve receptors and the woman experiences the urge to push.
The mother’s response is to contract abdominal muscles and the diaphragm.
What are the foetal factors that influence passage?
Lie (Relationship between the long axis of foetus and long axis of maternal spine)
Presentation (Cephalic or breech (~4 - 5%)
Attitude (Flexion of head is good, brow presentation is undeliverable)
Position (relationship between presenting part and mother’s pelvis)
Ability to alter head size (fontonelles and sututes that can mould)
How is foetal position adjusted during delivery?
Whatever hits pelvic floor rotates anteriorly
What is the denominator of foetal position?
The foetal occiput which needs to face anteriorly in the mother.
What is moulding an indicator of?
Moulding of the foetal head indicates difficulty of the head fitting through the pelvic cavity.
How can progress of labour be monitored?
Abdominal palpations (Confirm lie is longitudinal, foetal position is cephalic, position of foetal back, attitude of good flexion and position occipital lateral or anterior)
Vaginal examinations (Progressive effacement and dilatation of cervix (1cm an hour during active phase of labour), progressive descent of presenting part, Assess flexion and position)
Palpation of contractions (Frequency, length, and strength)
What does cervicograph do?
Provides graphic representation of the progress of cervix during labour.
What do the alert line and action line refer to?
Cervical opening needs to be monitored; during the latent phase it is OK for the cervix to take long to open to 4cm. However, during the active phase we need to see 1cm per hour.
Alert line means careful assessment is needed.
Action line means action needs to be taken (I.e oxytocin infusion to stimulate contractions)
What should be monitored during labour?
Cervicograph (monitor cervix size and contractions)
Maternal well-being (Vital signs, input and output, pain management, Continuous supportive environment) [ensure bladder is not distended]
How can pain be managed in labour?
Many choices (epidural, opioids, inhalational)
Natural methods (water / massages / heat / position / aromatherapy)
Support (positioning / caregiving / psychological support)
How is foetal wellbeing monitored?
Foetal heart rate is measured (110 - 160 bpm)
What are the cardinal movements of labour?
Engagement (descent has progressed so that maximum diameter of foetal head has passed through the pelvic brim)
Descent continues and occiput reaches the pelvic floor. Occiput begins to rotate on the pelvic floor
Once rotation is complete face starts to sweep the pelvic floor and the head begins to stretch the perineum
Head further extends the perineum and delivers
The foetal head realigns to the A-P plane of the shoulders, the internal shoulders rotate on the pelvic floor.
Anterior shoulder is under the symphysis pubis and delivers by lateral flexion followed by delivery of posterior shoulder
What must be monitored during the third stage of labour?
It begins after delivery of baby and involves separation and expulsion of the placenta and membranes and control of haemorrhage from the placental site.
What must be done immediately after delivery?
Detection of any postpartum complications
Promotion of early mother-baby interaction
Initiation of breastfeeding
