8- Complicated pregnancy (complicated labour) Flashcards
cardiotocography (CTG) measures
o Fetal heart rate
o Uterine contractions
when are CTGs used
in third trimester of complicated pregnancies
how are readings obtained for CTG
1) 2 transducers on pregnant abdomen
- Purple- fetal heart rate (placed on anterior shoulder of foetus)
- Pink- uterine contraction (measures tension of abdominal wall)
2)Mother also presses a button when she feels fetal movements
Interpreting CTG
- Top trace- fetal heart trace
- Middle- when women feels fetal movement
- Bottom- tocometry trace
CTG divided into 10 minute blocks represented by 10 small boxes
Interpreting CTG
- Top trace- fetal heart trace
- Middle- when women feels fetal movement
- Bottom- tocometry trace
CTG divided into 10 minute blocks represented by 10 small boxes
Interpreting CTG
DR C BRAVADO
define risk
Assessing risk factors of pregnancy i.e. high risk or low risk
Examples:
- Meconium stained liquor
- Fever
- IUGR
contractions
frequency
duration
freqeucny of contractions
Baseline rate
average heart rate of the fetus
normal FHR
110-160 bpm
fetal tachy
> 160bpm
Causes
- Fetal hypoxia
- Chorionamnionitis (take temp of mum)
variability
beat to beat variability
- From 5-25 BPM= normal
-E.g. Good variation:
bad variation
bad variation= minimal variation
causes of decreased variability
- Sleep (should be shorter than 40 mins)
- Drugs e.g. opiate/ mag sulphate
- Fetal hypoxia
accelerations
- Increase in FHR by >15 bpm for >15s
- sign of a healthy fetus
decelerations
Reduced fetal heart rate by more than >15bpm for >15s
Split into:
1) Early
2) Variable
3) Late
early decelerations
Trough of deceleration coincides with peak of contraction
* Secondary to head compression – physiological and not pathological
variable decelerations
- Most common type
- Vary in shape, form and timing in relation to contractions
- Cause: umbilical cord compression
- Concerning characteristics
~~~
o Lasting >60s
o Biphasic shape (W shape)
o No shouldering – sign foetus is compensating well
o Reduced baseline variability within deceleration
o Failure to return to baseline
~~~
late decels
- Starts after the contraction begins and persists after the contraction ends
- Secondary to
~~~
o Maternal hypotension
o Pre-eclampsia
o Uterine hyperstimulation
~~~
Overall assessment
- Normal
- Suspicious: a single non-reassuring feature
- Pathological: two non-reassuring features or a single abnormal feature
- Need for urgent intervention: acute bradycardia or prolonged deceleration of more than 3 minutes
The outcome of the CTG will guide management, such as:
- Escalating to a senior midwife and obstetrician
- Further assessment for possible causes, such as uterine hyperstimulation, maternal hypotension and cord prolapse
- Conservative interventions such as repositioning the mother or giving IV fluids for hypotension
- Fetal scalp stimulation (an acceleration in response to stimulation is a reassuring sign)
- Fetal scalp blood sampling to test for fetal acidosis
- Delivery of the baby (e.g. instrumental delivery or emergency caesarean section)
management of fetal bradycardia
Fetal Bradycardia
There is a “rule of 3’s” for fetal bradycardia when they are prolonged:
- 3 minutes – call for help
- 6 minutes – move to theatre
- 9 minutes – prepare for delivery
- 12 minutes – deliver the baby (by 15 minutes)
physiology of fetal hypoxia: COMPENSATED RESPONSE
fetus is unable to increase RR. Therefore a number of adaptations to decrease myocardial workload to reduced the amount of oxygen required:
1) Reduced fetal heart rate causing deceleration
- decreases myocardial workload to use less oxyegn
2) Reduced movement to reduce heart rate
3) Release of catecholamines- conserves oxygen
* Increase HR to get oxygenated blood from placenta
* Peripheral vasoconstriction redistribute blood
* Glycogenolysis to increase energy supply
THIS IS A COMPENSATED RESPONSE- HOWEVER THIS CANNOT LAST FOREVER
physiology of hypoxia : DECOMPENSATED
Compensation cannot last forever
1) Hypoxia to brain
- Loss of baseline FHR variability
2) Myocardial hypoxia and acidosis
- Unstable baseline
- Stepwise pattern to death
ABCE approach to predict next change in CTG
complications in labour
1) premature labour
2) failure to progress
3) malpresention/ malposition
3) fetal distress
4) VBAC
5) Shoulder dystocia
premature labour definitions
Rupture of membranes (ROM): The amniotic sac has ruptured.
Spontaneous rupture of membranes (SROM): The amniotic sac has ruptured spontaneously.
Prelabour rupture of membranes (PROM): The amniotic sac has ruptured before the onset of labour.
Preterm prelabour rupture of membranes (P‑PROM): The amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm).
Prolonged rupture of membranes(also PROM): The amniotic sac ruptures more than 18 hours before delivery.
define prematurity
birth before 37 weeks gestation
babies are considered non-viable below
23 weeks gestation
- at 23 weeks 10% chance of survival
- 24 weeks onwars- increased chance of survival- full resus offered
prophylaxis of preterm labour
1) Vaginal progesterone
2) Cervical cerclage
vagianl progesterone prophylaxis: MOA
Offered to women with a cervical length less than 24mm on vaginal US between 16 and 24 weeks
Given vaginally
- maintains pregnancy
- prevents labour by decreasing activity of the myometry and preventing cervix remodelling
Cervical cerclage
offered to women with a cervical length elss than 25mm on vaginal US between 16 and 24 weeks who have had a previous premature birth or cervical traum (colposcopy and cone biopsy)
- Involves putting a stitch in the cervix to add support and keep it closed.
- This involves a spinal or general anaesthetic.
- The stitch is removed when the woman goes into labour or reaches term.
rescue cervical cerclage
may also be offered between 16 and 27 + 6 weeks when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery.
Preterm Prelabour Rupture of Membranes
Preterm prelabour rupture of membranes is where the amniotic sac ruptures, releasing amniotic fluid, before the onset of labour and in a preterm pregnancy (under 37 weeks gestation).
diagnosis of P_PROM
1) speculum examiantionr evealing pooling of amniotic fluid in the vagina
2) tests on the fluid to confirm it is amniotic fluid
- Insulin-like growth factor-binding protein-1 (IGFBP-1) is a protein present in high concentrations in amniotic fluid, which can be tested on vaginal fluid if there is doubt about rupture of membranes
- Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
diagnosis of P_PROM
1) speculum examiantionr evealing pooling of amniotic fluid in the vagina
2) tests on the fluid to confirm it is amniotic fluid
- Insulin-like growth factor-binding protein-1 (IGFBP-1) is a protein present in high concentrations in amniotic fluid, which can be tested on vaginal fluid if there is doubt about rupture of membranes
- Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
management of P-PROM
-Prophylactic antibitoics to prevent chorioamnionitis
- Induction of labour (from 34 weeks)
- Expectant management until 37 weeks
which Abx to prevent chorioamnionitis if P-PROM
d erythromycin 250mg four times daily for ten days, or until labour is established if within ten days.
Preterm Labour with Intact Membranes
Preterm labour with intact membranes involves regular painful contraction and cervical dilatation, without rupture of the amniotic sac.
diagnosing preterm labour with intact membranes
- Less than 30 weeks gestation, clinical assessment (speculum exam for cervical dilatation) alone is enough to offer management of preterm labour.
- More than 30 weeks gestation, a transvaginal ultrasound can be used to assess the cervical length. When the cervical length on ultrasound is less than 15mm, management of preterm labour can be offered. A cervical length of more than 15mm indicates preterm labour is unlikely.
- Fetal fibronectin is an alternative test to vaginal ultrasound. Fetal fibronectin is the “glue” between the chorion and the uterus, and is found in the vagina during labour. A result of less than 50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
management for preterm labour*
- Fetal monitoring (CTG or intermittent auscultation)
- Tocolysis with nifedipine: nifedipine is a calcium channel blocker that suppresses labour
- Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality
- IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain
- Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth
tocolysis
- involves using medications to stop uterine contractions.
- Nifedipine, a calcium channel blocker, is the medication of choice for tocolysis
Antenatal Steroids
Giving the mother corticosteroids helps to develop the fetal lungs and reduce respiratory distress syndrome after delivery. They are used in women with suspected preterm labour of babies less than 36 weeks gestation.
An example regime would be two doses of intramuscular betamethasone, 24 hours apart.
magnesium sulfate
Giving the mother IV magnesium sulfate helps protect the fetal brain during premature delivery. It reduces the risk and severity of cerebral palsy. Magnesium sulphate is given within 24 hours of delivery of preterm babies of less than 34 weeks gestation. It is given as a bolus, followed by an infusion for up to 24 hours or until birth.
magnesium toxicity
Mothers need close monitoring for magnesium toxicity at least four hourly. This involves close monitoring of observations, as well as tendon reflexes (usually patella reflex). Key signs of toxicity are:
- Reduced respiratory rate
- Reduced blood pressure
- Absent reflexes
failure to progress
Failure to progress refers to when labour is not developing at a satisfactory rate. This increases the risk to the fetus and the mother. It is more likely to occur in women in labour for the first time compared with those that have previously given birth.
Progress in labour is influenced by the three P’s:
- Power (uterine contractions)
- Inadequate contractions
- maternal exhaustion - Passenger (size, presentation and position of the baby)
- malposition/ presentation
- cephalopelvic disproportton - Passage (the shape and size of the pelvis and soft tissues)
- obstructed labour
Partogram showing normal progress in labopur
Ideally a women would progress (cervical dilatation) 1 cm every hour
- Yellow = progress
- Purple = stop line (to show if a labour is progressing too slowly and an intervention needs doing)
There are two lines on the partogram that indicate when labour may not be progressing adequately. These are labelled “alert” and “action”. The dilation of the cervix is plotted against the duration of labour (time). When it takes too long for the cervix to dilate, the readings will cross to the right of the alert and action lines.
Partogram showing dysfunctional labour
management of labour based on partogram
Crossing the alert line is an indication for amniotomy (artificially rupturing the membranes) and a repeat examination in 2 hours.
Crossing the action line means care needs to be escalated to obstetric-led care and senior decision-makers for appropriate action.
Delay in the second stage is when the active second stage (pushing) lasts over:
- 2 hours in a nulliparous woman
- 1 hour in a multiparous woman
management of dysfunctional labour caused by infefficient uterine contractions
Augment labour with Oxytocin
- Beware: can be more liberal with oxytocin in nulliparous uterus than multiparous- can rupture!
- Oxytocin use also more liberal in people who have had c -section- scar more rupturable (VBAC)
dysfunctional labour: the passenger
Passenger refers to the four descriptive qualities of the fetus:
- Size
- Attitude
- Lie
- Presentation
passenger: szie
Large babies (macrosomia) will be more difficult to deliver, and there may be issues such as shoulder dystocia. The size of the head is important as this is the largest part of the fetus.
passenger: attitude
Attitude refers to the posture of the fetus. For example, how the back is rounded and how the head and limbs are flexed.
passenger: lie
Lie refers to the position of the fetus in relation to the mother’s body:
- Longitudinal lie – the fetus is straight up and down
- Transverse lie – the fetus is straight side to side
- Oblique lie – the fetus is at an angle
Passenger: presentation
refers to the part of the fetus closest to the cervix:
1) Cephalic presentation – the head is first (position is described as the part of the head which is in the presenting part)
o Face- when head fully extended
o Brow- when head partially extended
2) Shoulder presentation – the shoulder is first
3) Breech presentation – the legs are first.
breech psoitions
- Complete breech – with hips and knees flexed (like doing a cannonball jump into a pool)
- Frank breech – with hips flexed and knees extended, bottom first
- Footling breech – with a foot hanging through the cervix
A best C worst
When there are problems in the second stage of labour, interventions may be required depending on the situation. Possible interventions include:
Changing positions
Encouragement
Analgesia
Oxytocin
Episiotomy
Instrumental delivery
Caesarean section
Management of Failure to Progress
- Amniotomy, also known as artificial rupture of membranes (ARM) for women with intact membranes
- Oxytocin infusion
- Instrumental delivery
- Caesarean section
delay in the third stage
The third stage of labour is from delivery of the baby to delivery of the placenta. Delay in the third stage is defined by the NICE guidelines (2017) as:
- More than 30 minutes with active management
- More than 60 minutes with physiological management
management of third stage
Active management involves intramuscular oxytocin and controlled cord traction.
- shortens the third stage
- reduces risk of bleeding
active management of the third stage can be associated with
N and V
Placental delivery
- aim to deliver in one peice
- examine to ensure it is complete and no tissue remains in uterus
- massage uterus until contracted and firm
management of breech baby
First line: External cephalic version (ECV) to attempt to turn fetus
Second line: Vaginal delivery or elective caesarean section
Breech presentation: to give birth vaginally or via C-section
- Vaginal birth safer for mother (40% chance of requring an emergency c-section when vaginal birth is attempted)
- C-section safer for baby
External cephalic version (ECV)
is a technique used to attempt to turn a fetus from the breech position to a cephalic position using pressure on the pregnant abdomen. It is about 50% successful.
External cephalic version is used in babies that are breech:
- After 36 weeks for nulliparous women (women that have not previously given birth)
- After 37 weeks in women that have given birth previously
Measures taken before ECV
- Tocolysis - subcut terbutaline (beta agonist) to reduce contractility of myometrium
- Rhesus-D negative women given anti-D prophylaxis
complications of breech
- Head becomes trapped
- Cord prolapse
- Intracranial haemorrhage
- Internal injury
Causes of non reassuring CTG
- Uterine hyperstimulation (iatrogenic – e.g. if too much oxytocin)
o If too many contractions can cause fetal distress e.g. like being consistently dunked under water vs it happening once – think can reduce blood flow through the cord - Hypotension e.g. maternal hypotension – lying on back or epidural
- Poor fetal tolerance of labour (e.g. IUGR- if smaller baby lower tolerance of labour)
- Cord compression- fetal hypotension caused by cord compression (will come and go with contraction)
- Infection e.g. Chorioamnionitis
- Maternal disease
investigations for fetal distress
1) Non reassuring CTG
- Baseline tachycardia or bradycardia
- Reduced baseline variability (flat)
- Absence of accelerations (non-reactive)
- Presence of decelerations
2) Contractions (3-4 times every 10 mins goal)
3) Passage of meconium (has baby opened bowels)
- Sign of fetal distress baby goes into high risk
How accurate are CTGs for fetal distress
- High sensitivity but low specificity
o If normal good
o If not normal – 50/50 chance of it being normal or bad - Confirm by fetal acid-base status (fetal scalp blood sampling FBS)
- If unable to do FBS, deliver by speediest route
management of fetal distress syndrome
- Rectify reversible causes e.g. maternal hypotension
- Put women in lateral position
- Stop oxytocin
- Confirm compromise by blood sampling where possible
- Deliver by speediest route if unable to correct or if significant acidosis
shoulder distocial
inability to deliver shoulder after dleivery of head
- anterior shoulder does not enter pelvic inlet
-
risk factors for shoulder dystocia
- macrosomic fetus
- fetus of diabetic mother
- rotetional instrumental delivery
risks of shoulder dystocia
- fetal dearth
- asphyxia with resulting hypoxic damage
- birth trauma (Erbs)
- maternal trauma (e.g. perineal tears)
why are we worried with shoulder dystocia when the babies head has been delivered
- Why do we worry: babies head comes out and it starts to gasp but it cannot expand lungs due to being wedged in birth canal
- Cord squashed -> no blood/ oxygen -> hypoxic
management of shoulder dystocia
1) McRoberts potion
o Get mother into a position where her knees are close to chest helps drop the sacrum
2) Suprapubic pressure
3) Other obstetric manoeuvres
- Woodscrew
-Lady on all fours
- Cutting pubic symphysis -> baby not likely to survive
Erbs palsy
neonatal preterm risks
- Neonataldeath
- Respiratorydistresssyndrome
- Chroniclungdisease
- Intraventricularhemorrhage
- Necrotizingenterocolitis
- Sepsis
- Retinopathyofprematurity
- <28weeks:
– physicaldisabilities,
– learningdisabilities,
– behaviouralproblems,
– visualandhearingproblems
risk of PPROM
– Prematurity
– Sepsis and chorioamnionitis – Cord prolapse
– Pulmonary hypoplasia
