Normal birth Flashcards
What are the general changes in pregnancy physiology?
- Skin pigmentation
- Body shape
- Altered gait and posture
Normal birth is defined by the WHO as:
- Spontaneous in onset
- Low risk at the start of labour
- Remaining low risk throughout labour and birth
- The newborn is born:
- Spontaneously
- In the vertex position
- Between 37 and 42 completed weeks gestation
- After birth, the woman and newborn are in good condition
What are the signs of imminent birth?
- Loss of operculum plug - when the cervix dilates the mucous plug (‘bloody’ show) dislodges from the cervical canal (may occur days before).
- Increasing frequency and severity of contractions and an urge to push, or open bowels
- Membrane rupture (this may not occur and active membrane rupture may be required if the head has been delivered intact)
- Bulging perineum
- Appearance of the presenting part at the vulva
What must be included in an antenatal hx?
- Gravida
- Parity
- Gestation
- Foetal movements
- Tightenings/contractions
- Vaginal loss
- Placenta
- Single/multiple
- Complications
- Urinary symptoms
- Blood group
- Rubella immune status
- Size of previous babies
- Gestational diabetes (macrosomic baby, shoulder dystocia risk)
- Mal-presentation
- Multiple pregancy
- Pre-eclampsia
- Placenta praevia
- Perinatal substance use
- Hx of obstetric or gynaecological disorder or emergency
Following spontaneous rupture of membranes the vagina should be inspected for what two occurences, and how is this done?
Cord presentation or prolapse, done by asking the mother to feel for the cord.
What should you request the mother do when the baby is crowning?
Actively push with each contraction.
Should analgesia be offered to pregnant women in labour?
What is the essential management of nuchal cord (cord around baby’s neck)?
Avoiding the early clamping or cutting of the cord, before the baby’s body is delivered.
What is the best way to keep the newborn warm? What is the added bonus of this?
Direct skin-to-skin contact with mother; cover both with blankets. This also promotes breastfeeding and bonding.
Mothers and newborns should be reassessed every ____ minutes.
Five minutes.
When should the cord be clamped?
Approximately three to five minutes after birth or when the cord stops pulsating.
Administration of IM ____ should be considered after delivery of the last fetus.
Oxytocin
Immediately massage the fundus after the placenta is birthed; how should the uterus feel?
Firm and central.
Should the fundus be massaged if the placenta is not delivered within twenty minutes? Why?
No, as it may contribute to uneven separation of the placenta.
How much blood should be lost after birthing the placenta?
200-300mL.
If blood loss after birthing the placenta is >500mL, what should it be rx as?
Primary post-partum haemorrhage.
True or false: the placenta should be kept for inspection by a midwife or doctor.
Newborns should be assessed for ____, ____, and ____.
- Breathing/crying
- Muscle tone
- Heart rate
What are the five points of an APGAR assessment?
- Appearance (colour)
- Pulse (HR)
- Grimace (reflex irritability)
- Activity (muscle tone)
- Respiration (respiratory effort)
What observations give an APGAR score of 0?
- Appearance - blue/pale
- Pulse - absent
- Grimace - no response
- Activity - limp
- Respiration - absent
What observations give APGAR scores of 1?
- Appearance - pink, extremities blue
- Pulse - <100
- Grimace - grimace
- Activity - some flexion/extension
- Respiration - slow/irregular
What observations give APGAR scores of two?
- Appearance - all pink
- Pulse - >100
- Grimace - vigorous cough
- Activity - active motion
- Respiration - good cry
What physiological changes in pregnancy increase risk of regurgitation/aspiration?
- Relaxed gastro-oesophageal sphincter
- Increased intragastric pressure
- Delayed gastric emptying due to upward pressure on the diaphragm from the gravid uterus
At 12 weeks, tidal volume increases by ____%.
20%
At 40 weeks, tidal volume increases by ____%.
40%
An increase in tidal volume in pregnancy is at what expense, and what does this mean?
A proportionate decrease in inspiratory and expiratory response and residual capacity. This means the pt has a reduced ability to compensate for any increase in oxygen demand.
By how much does pregnancy increase oxygen demand, and how does the body compensate for this?
15%, compensated for with a small increase in RR as well as the increased tidal volume.
What haematological changes occur in pregnancy?
- 50% increase in blood volume by third trimester, possibly higher for multiple infants
- Plasma volume increased by 50%; RBC increased by 18%
- Physiological anaemia; haemodilution
- Neutrophils increase
- Eosinophils increase during pregnancy then decrease during labour
- Depression of cell-mediated immunity
- Hypercoagulopathy
Pregnant pts will initially compensate for blood loss with their increased circulatory volume, but this is comes at the expense of what?
Blood supply to the fetus.
Why should a pt in late second or third trimester never be laid supine?
To avoid vena caval compression, which can lead to maternal and fetal hypoxia.
Heart position, cardiac output, uterine perfusion, renal refusion.
What significant CVS changes occur in pregnancy?
- Heart is pushed upwards, sometimes causing systolic or diastolic murmurs
- Cardiac output is significantly increased
- Uterine perfusion is 500mL/min at term
- Renal perfusion increases by 400mL/min
What are the hormonal causes for the CVS changes in pregnancy?
- Progesterone
- Oestrogen
- Prostaglandins
Note: in general terms
What is the mechanical cause for CVS changes in pregnancy?
Growth and development of organs requiring increased blood supply
What physical changes occur in the respiratory system during pregnancy?
- Airway changes
- Altered shape of thorax
- Diaphragm displaced by gravid uterus (by term)
- Diaphragmatic to thoracic breathing
Answer in mL
By how much does the expiratory reserve volume decrease?
200mL (usually about 1000mL)
Alveolar respiration (oxygen transfer) increases by how much during pregnancy?
40%
What hormones are present during pregnancy, and what are their functions?
- Relaxin
- Growth hormone
- Increases ligament and tendon laxity
- Prepares for birth
- Oestrogen
- Fertilisation and maintaining pregnancy
- Growth stimulators
- Progesterone
- Relaxes smooth muscle
- Vasodilation (haemodynamics)
- Reduced gut motility
- Oxytocin
- Essential for labour, third stage, and breastfeeding.
- Prolactin
- Breast milk production
What is commonly caused by changes to the oesophagus?
Reflux/oesophagitis (seen in two thirds of pregnant women)
What are some effects of changes to the stomach during pregnancy?
- Reduced gastric emptying
- Constipation (common)
- May affect absorption of oral mx
- Increased risk of acid aspiration
What does ‘gravida’ mean?
Number of pregnancies
What is ‘primigravida’?
First pregnancy
What is ‘primipara’?
First time birthing mother
What is ‘multiparous’?
More than one pregnancy.
What does SROM commonly stand for?
Spontaneous rupture of membranes.
What is ‘parity’?
Number of pregnancies carried to viable age.
The first stage of labour spans which events?
Onset of labour to full dilation of the cervix.
What occurs during the latent phase (prior to active first stage)?
- May last 6-8 hours to 1-2 days in primiparas
- Contractions may vary - 1-2:10min, mild, 20-40 seconds in duration
- Cervix effaces from 3cm to 0.5cm long (usually soft and stretchy)
- Cervix dilates from 0-4cm
When it starts and ends, rate of contractions, and how long it lasts.
What occurs during the active first stage?
- Begins when cervix is 3-4cm dilated and is complete when fully dilated
- Cervix dilates more rapidly
- 3-4:10min moderate/strong contractions, 50-70 seconds in duration
- Usually lasts 1-2hours/cm in primiparas
- Usually lasts 1hour/0.5-1cm in multiparas
Describe the transitional phase of the first stage.
- When the cervix is 8-9cm to fully dilated, or when expulsive contractions are felt
- Often a brief lull in contractions
- Contractions can seem to change to be less intense, with a break between
- Mood changes are common
The second stage of labour spans which events?
Full dilation of the cervix to expulsion of the fetus.
What happens, rate of contractions, and how long it takes.
Describe the second stage of labour.
- Characterised by urge to push
- Often longer breaks between contractions (3:10)
- Can take up to 2 hours in a primipara, 1 hour in a multipara, but usually takes less than 15 minutes
What is the definition of the ‘mechanisms of labour’?
The typical sequence of positions assumed by the fetus as it descends through the pelvis during labour and delivery. Also known as cardinal movements.
List the cardinal movements (a.k.a. mechanisms of labour).
- Descent
- Flexion
- Internal rotation
- Crowning
- Extension
- Restitution
- Lateral flexion
The third stage of labour spans which events?
Birth of the infant to expulsion of the placenta and membranes.
Describe the third stage of labour.
- Separation of the placenta from the wall of the uterus
- Expulsion of the placenta and membranes (greatest risk of PPH)
What is the fourth stage of labour?
The two hours following the birth of the infant that includes breastfeeding and monitoring
What are the options for prehospital analgesia, and the pros and cons for each?
- Methoxyflurane
- Easy and fast to use
- Pregnancy category class C - not recommended
- Crosses the placenta - CNS and respiratory depressant
- Morphine
- Effective in early labour
- Fast and easy IM administration
- Pregnancy category C - not recommended
- Limited effect in active labour
- SE of maternal drowsiness, N+V
- Crosses the placenta
- Fentanyl
- Same pros as morphine
- More potent and less respiratory effects than morphine
- Same cons as morphine
True or false: the lithotomy position is highly recommended for normal births.
What elements should be documented?
- Onset of active labour (regular painful contractions)
- Rupture of membranes
- Commencement of effective pushing
- Head on view
- Time of head
- Time of birth
- Birth of placenta
- Liquor
- Name of the accoucheur and witnesses
- eARF for baby
- Complications
- Birth position
- EBL
What is Syntocinon?
A synthetically produced oxytocin
What is the dosage of oxytocin and what is the effect?
10IU (international units) given IM (vastus lateralis); this dosage and route causes a sustained tetanic uterine contraction.
What is the onset and duration of oxytocin?
2-3 minute onset, 30-60 minute duration.
What are the contraindications for oxytocin?
- KSAR
- Second fetus
What are the possible side effects of oxytocin?
- N+V
- Hypertension
List the signs of placenta separation.
- Lengthening of the cord
- Fresh show of blood
- Fullness in the intriotus
- Contracted uterus sits at the umbilicus
- Cord does not move when performing counter traction
- Visible membrane
- If unsure, wait longer and seek confirmation.
List the steps of modified active mx of the third stage.
- Gain consent
- Place baby skin-to-skin
- Check for unexpected second infant
- Administer oxytocin
- Wait for white
- Change linen/bluey
- Clamp and cut
- Wait for signs of separation
- Controlled cord traction with counter traction to deliver placenta
- Twist placenta at intriotus to deliver and ensure membranes are captured
- Check fundus and perineum
- Monitor PVH and VS
List what should be checked for when examining the placenta in the fourth stage.
- Three vessels in cord (2xA, 1xV)
- Ragged membranes
- Insertion of cord
- Battledore
- Central
- True knots
- False knots
Describe possible complications of the fourth stage of labour on the maternal side.
- Missing cotyledons
- Placental infarctions
- Succenturiate lobes
- Excess clots
True or false: BSL is necessary on a newborn.
What is preferred, fentanyl or morphine?
Fentanyl.
True or false: gums can become swollen and bleed easily during pregnancy.
What is the reason for increased blood flow to the skin during pregnancy?
To control body temperature, which increases by ~1ºC during pregnancy.
Which side should a pt be tilted towards to prevent supine hypotensive syndrome?
L) is preferred in texts but the IVC is fairly central and either L) or R) will suffice.
Note that turning the pt to the L) will face them away in the ambulance.
What is a ‘tocolytic effect’?
Reduces the ability of the uterine muscle to contract; increases risk of bleeding.
Note: this is given to prevent premature labour.
How long can physiological third stage take?
Up to one hour
What is a risk of physiological third stage?
Bleeding (500mL/minute)
Can oxytocin be given for active mx of third stage and then again for prevention of PPH?
At which measurements are clamps placed, and where do we cut?
10, 15, and 20. Cut between 15 and 20 (two on baby’s side, one on mother’s). If another clamp is available, clamp near the perineum (shows lengthening and helps with traction).
What is active third stage mx and when is it used?
Oxytocin given with first shoulder presentation, used in circumstances with likely PPH/bleeding disorders.
What is modified active third stage mx?
Waiting for the umbilical cord to stop pulsating, then clamping and giving oxytocin.
What is physiological third stage?
No oxytocin (relies on endogenous oxytocin), no traction applies to umbilical cord (can take longer for placenta to birth). Carries an increased risk of PPH.
