MANAGEMENT OF LABOUR AND DELIVERY Flashcards
Choices for place of birth
Home
Midwifery unit/birthing centre
Hospital
Advanatges of home birth
being in familiar surroundings, where you may feel more relaxed and better able to cope - more relaxed = more oxytocin released = easier birth
not having to interrupt your labour to go into hospital
not needing to leave your other children, if you have any
not having to be separated from your partner after the birth
increased likelihood of being looked after by a midwife you have got to know during your pregnancy
lower likelihood of having an intervention, such as assisted births or episiotomy
Associated with higher rates of spontaneous vaginal births
Considerations for a home birth
You may need to transfer to hospital if there are complications. For nulliparous women 45% will go to hopsital, for multiparous only 12%
Epidurals are not available at home
Doctor or midwife may recomemend giving birth in hospital e.g. if twins or breech
Advanatges of a birth centre or midwifery unit?
Being in surroundings where you may feel more relaxed than at jppsital and better able to cope with labour
More likely to be looked after by a midwife you got to know during your preganncy
The unit might be much closer to your home than the hopsital
Lower likelihood of having an intervention such as forceps or ventouse than giving birth in hospital
Considerations for choosing to deliver in a birthing unit?
You may need to be transferred to a hospital if there are any complications
No access to epidural
Your doctor or midwife may recommend you give birth in a hospital
Advanatges to hospital birth?
Direct access to obstetricians if labour becomes complicated
Direct access to anaesthetists who can give epidurals and GA
Access to neonataologistss and SCBU if any problems with baby
Cosiderations for choosing to deliver at hospital?
You may go home directly from labour ward or you may be moved to postanatal ward
In hospital you may be looked after by a different midwife from the one who looked after you during your pregnancy
More likely to have an epidural, episiotomy or a forceps or ventouse delivery in hospital
Risk factors for preterm labour?
Previous premature birth
Multiple gestations
Women with certain anomalies of reproductive organs e.g. cervical incompetence
Med conditions: UTI, STI, hypertension, PV bleeding after 24/40, development anomalies in foetus, IVF preganncy, being underweight or obese before pregnancy, <6 months between birth and starting another pregnancy, placenta pre via, diabetes, blood clotting problems, PPROM
Women<18 or women >35
Having no prenatal care
Smoking, alcohol, drugs
Stress
Domestic violence
Long working hours with long periods of standing
Impact of BMI on the choice of place of birth
In general the higher the BMI at booking, the greater the likelihood of complications e.g. unplanned C-section, PPH, transfer to an obestetric unit, stilllbirth, neonatal death
This may be something for the pt to think about when planning their place of birth
To which women would you offer prophylactic vaginal progesterone and cervical cerclage?
women who have both:
Hx of spontaneous preterm birth (up to 34+0 weeks of pregnancy) or loss (from 16+0 weeks of pregnancy onwards)… and…
results from a transvaginal ultrasound scan carried out between 16+0-24+0 weeks of pregnancy that show a cervical length of 25 mm or less.
Consider in women who only have 1 of the above.
What is cervical cerclage?
This involves putting a stitch in the cervix to add support and keep it closed
The stitch is removed when the woman goes into labour or reaches term
What is “rescue” cervical cerclage?
16+0-27+6
When there is cervical dilatation without rupture of membranes - aims to prolong pregnancy to a viable gestation in a woman who was not previously identified as at risk for cervical insufficiency but later develops sign suggesting cervical weaknesss that may lead to preterm birth
What is vaginal progesterones moa for preventing preterm labour?
Given vaginally via a gel or pessary as prophylaxis for preterm labour
It decreases the activity of the myometrium and prevents the cervix remodelling in preparation for delivery
Classification of prematurity by WHO
Under 28 weeks: extreme preterm
28 – 32 weeks: very preterm
32 – 37 weeks: moderate to late preterm
What is PROM and P-PROM?
Prelabour ruptre of membranes - amniotic sac has ruptured before the onset of labour OR prolonged rupture of membranes where amniotic sac ruptures >18hrs before delivery
Preterm prelabour rupture of membranes - amniotic sap ruptured before onset of labour and before 37/40
How common is preterm prelabour rupture of membranes?
Happens in 2% of pregnancies but is associated with around 40% of preterm deliveries
Complications of P-PROM?
Foetus - Prematurity, infection or pulmonary hypoplasia, oligohydramnios, neonatal death, umbilical cord prolapse
Maternal - chorioamnionitis
How to confirm P-PROM?
Sterile speculum examination - look for pooling of amniotic fluid in posterior vaginal vault. If positive no other tests required.
If pooling of fluid is not observed… test vaginal fluid for placental alpha microglobulin-1 protein (PAMG-1) or Insulin-like growth factor binding protein-1 - If these are negative and no amniotic fluid is observed unlikely P-PROM
Ultrasound is not used routinely, but may facilitate diagnosis in cases where it remains unclear. Reduced levels of amniotic fluid within the uterus are more suggestive of membrane rupture.
Why will vaginal fluid contain insulin-like growth factor-binding protein-1 and placental alpha-microglobulin-1 in P-PROM?
They’re both present in amniotic fluid so will only be present in vaginal discharge if rupture of membranes has occured
(IGFBP-1 is produced by foetal membranes (amnion) and PAMG-1 is produced by the placenta)
Management of P-PROM?
admission
regular observations to ensure chorioamnionitis is not developing
As prophylaxis for chorioamnionitis - oral erythromycin 250mg 4 times a day for 10 days or until woman is in established labour
antenatal corticosteroids and magnesium sulfate should be considered
delivery should be considered at 34 weeks of gestation (although RCOG suggests offer expectant management until 37+0)
What is choriomanitis? What causes it? Whats the biggest risk factor?
Whats the Tx?
Infection of the amniotic fluid, membranes and placenta
Its a potentially life-threatening condition to both mother and foetus and is therefore considered a medical emergency
Usually as a result of an ascending bacterial infection
Biggest risk factor is PPROM which exposes the normally sterile environment of the uterus to potential pathogens
Prompt delivery of foetus and IV antibiotics is initial Tx
How to diagnose chorioamnionitis in a woman with P-PROM?
Fever, uterine fundal tenderness and maternal tachycardia
CRP, WBC
CTG for foetal heart rate - usually >160/min
What can cause PROM?
Physiologic weak ending of membranes combined with forces caused by uterine contractions
Infections
Genetic predisposition
Risk factors for PROM and P-PROM?
Smoking - especially <28/40
Previous PROM or preterm delivery
Vaginal bleeding during pregnancy
Lower genital tract infection
Invasive procedures e.g. amniocentesis
Polyhydramnios
Multiple pregnancy
Cervical insufficiency
Clinical features of PROM?
Painless pop-> gush of watery fluid leaking from vagina
Gradual leakage of watery fluid from vagina, damp underwear or a change in colour/consistency of vaginal discharge
Why is it important to avoid performing a digital vaginal exam in women with suspected PROM or P-PROM?
It has been shown to reduce the time between rupture of membranes and onset of labour
It is also more likely to introduce an ascending intrauterine infection
How do we diagnose preterm labour with intact membranes?
If suspected preterm labour and…
- 29+6 weeks of less advise Tx
- 30+0 weeks pregnant or more, consider transvaginal USS measurement of cervical length as a diagnostic test to determine the likelihood of birth within 48 hrs. If cervical length is 15mm or less then view the woman as being in diagnosed preterm labour and offer Tx
Foetal fibronectin can be used instead for women 30+0 weeks pregnant or more if transvaginal USS measurement is indicated but is not available or acceptable. If positive view woman as being in diagnosed preterm labour and offer Tx
Why can foetal fibronectin testing be used as a diagnostic test to determine the likelihood of birth within 48 hours in women who are 30+0 weeks pregnant or more?
Foetal fibronectin is a protein produced by foetal membrane and the placenta. Its role is in adhesion of the foetalk sac to the uterine lining
If its found in vaginal fluid it can suggest preterm labour is likely
Management for improving outcomes in preterm labour?
Foetal monitoring with CTG or intermittent auscultation
Tocolysis with nifedipine
Maternal corticosteroids
IV magnesium sulphate
Delayed cord clamping
What is tocolysis?
Medications to delay the delivery of a foetus to suppress premature labour
What drug is most often given for tocolysis? how does it work?
Nifedipine
It’s a calcium channel blocker that relaxes uterine wall muscle decreasing contractions and prolonging time to delivery. Allows more time to administer corticosteroids for foetal lung maturity - not its only used for short time i..e ~48 hours
Who do you give nifedipine for tocolysis in women with intact membranes and suspected preterm labour?
Women between 24+0 - 33+6 weeks
What can you use for tocolysis if nifedipine is contraindicated?
An oxytocin receptor antagonist such as atosiban
Purpose of giving maternal corticosteroids to women in suspected or established preterm labour?
Reduces the severity of lung disease of prematurity by accelerating lung maturation
What corticosteroids are used in suspect premature labour to mature foetal lungs?
Betamethasone and dexamethasone
Which women in preterm labour should be offered maternal corticosteroids?
Women between 24+0 - 35+6 weeks
Note women less than 34+0 should have a single repeat course if they haven’t given birth within 7 days and they are at very high risk of giving birth in the next 48 hours
But be aware in women <30+0 weeks or in babies with suspected growth restriction, of the possible impact on foetal growth of a repeat course of maternal corticosteroids
Purpose of giving magnesium sulphate to women in preterm labour?
For neuroprotection of the baby - reduces risk and severity of cerebral palsy
Who should be offered magnesium sulphate in preterm labour?
Women between 24+0-33+6
In established preterm labour OR having a planned preterm birth within 24 hours
How do you give magnesium sulphate in preterm labour?
Give a 4 g intravenous bolus of magnesium sulfate over 15 minutes, followed by an intravenous infusion of 1 g per hour until the birth or for 24 hours (whichever is sooner).
What should you monitor whilst giving a woman in preterm labour magnesium sulphate?
Monitor at least every 4 hours for clinical signs of magnesium toxicity
Pulse, BP, RR, deep tendon reflexes
(signs of magnesium toxicity is reduced RR, hypotension and absent reflexes)
Look out for reduced urine output or other evidence of renal failure
Foetal monitoring options in preterm labour?
Cardiotocoography or intermittent auscultation
In some scenarios… foetal scalp electrodes and foetal blood sampling
From which week can the sonicaid be used for foetal monitoring?
From 16 weeks
From which week can the pinnard stethoscope be used for foetal monitoring?
From 16 weeks
From which week can the CTG be used for foetal monitoring?
From 26 weeks onwards
When can foetal scalp electrode be used for foetal monitoring?
Only in labour and when waters have broken!
Note this is a version of CTG. used instead of the abdominal transducer
What is Dawes Redman?
A software that analyses the CTG
Gives an objective value as CTG is otherwise highly subjective
Must not be used for intrapartum CTG analysis as it can’t be used in the presence of uterine contractions
What is cardiotocography?
Electronic foetal monitoring to measure foetal heart rate and the contractions of the uterus
How do you set up CTG?
Place 1 transducers above the foetal heart to monitor foetal heartbeat - it uses Doppler US
Place the other transducer near the fundus of the uterus to monitor the uterine contractions - it assesses the tension in the uterine wall
Mneumonic for CTG reading?
DR C BRAVDO
DR - Define RIsk
C - Contractions
BR- Baseline rate
A - Accelerations
V - Variability
D - Decelerations
O - overall impression
What are the 5 key features to look for on a CTG?
Contractions – the number of uterine contractions per 10 minutes
Baseline rate – the baseline fetal heart rate
Variability – how the fetal heart rate varies up and down around the baseline
Accelerations – periods where the fetal heart rate spikes
Decelerations – periods where the fetal heart rate drops
What does too little or too many contractions on CTG indicate?
How many should there be?
Too little - labour not progressing
Too many - uterine hyperstimulation which can lead to foetal compromise
Should be 3-5 contractions in 10 min window lasting 40-60 seconds each
What is normal baseline foetal HR on CTG? What is abnormal?
110-160
Non-reassruaing is 100-109 and abnormal is <100 or >180
What is normal variability and what is abnormal?
Normal variability is 5-25
Non-reassuring is <5 for 30-50 mins or >25 for 15-25 mins
Abnormal is <5 for over 50 mins or >25 for over 25 mins
What can cause reduced baseline variability on CTG?
Foetus sleeping - this shouldn’t last >40 mins though
Foetal acidosis due to hypoxia
Foetal tachycardia
Drugs: opiates, benzos, methyldopa, MgSO4
Prematurity
Congenital heart abnormalities
What can cause foetal tachycardia?
Fetal hypoxia
Chorioamnionitis
Hyperthyroidism
Fetal or maternal anaemia
Fetal tachyarrhythmia
What can cause foetal bradycardia?
Prolonged cord compression
Cord prolapse
Epidural and spinal anaesthesia
Maternal seizures
Rapid fetal descent
Note prolonged bradycardia (<80 for >3 mins) indicates severe hypoxia
Note its common to have baseline HR 100-130 in post date gestation and occiput posterior or transverse positions
What are accelerations on a CTG?
Abrupt increases in the baseline foetal HR of >15 bpm for >15 seconds
What do accelerations on CTG tell us?
They are reassuring - a sign of a healthy foetus
The absence of accelerations with an otherwise normal CTG is of uncertain significance
What are decelerations on a CTG?
abrupt decrease in the baseline fetal heart rate of greater than 15 bpm for greater than 15 seconds
What does a deceleration on CTG represent?
Foetus reduces its HR in response to hypoxic stress. This is to preserve myocardial oxygenation and perfusion
What is an early deceleration on CTG?
What causes it?
These are decelrations that start when the uterine contraction begins and recovers when uterine contractions stop
Due to increased foetal ICP causing increased fatal tone during contractions. Physiological not pathological!
What is variable deceleration on CTG?
What causes it?
Decelerations with variable recovery phase. No relationship to uterine contractions.
Usually caused by umbilical cord compression. Often see shoulders of decelrations where acceleration of the foetal heart rate before and after the deceleration occurs. Their presence indicates the foetus is not yet hypoxic and is adapting to the reduced blood flow.
Variable decelrations without the shoulders are more worrying as it suggests the foetus is becoming hypoxic!
What is a late deceleration on CTG?
What causes it?
These decelrations begin at the peak of uterine contraction and recover after the contraction ends
It indicates insufficiency blood flow to the uterus and placenta, so blood flow to foetus is significantly reduces causing foetal hypoxia and acidosis
Causes:
Maternal hypotension
Pre-eclampsia
Uterine hyperstimualtion
What is prolonged deceleration on CTG?
A deceleration that lasts>2 mins
If it lasts between 2-3 mins its classified as non-reassuring
If it lasts >3 minutes its immediately classed as abnormal
What is a sinusoidal pattern on CTG?
What does it indicated?
A smooth, regular, wave-like pattern with a frequency of around 2-5 cycles in 1 minute. Stable baseline rate and no beat to beat variability
Indicates either:
- severe foetal hypoxia
- severe foetal anaemia
- foetal/maternal haemorrhage
What are the 3 ways a CTG can be described in the “overall Impression”?
Reassuring
Suspicious
Abnormal
Reassuring signs on CTG?
Baseline rate 110-160
Baseline variability 5-25bpm
No/only early decelerations. Or variable decelerations with no concerning characteristics for <90 minutes
Non-reassuring signs on CTG?
Baseline HR 100-109 or 161-180bpm
Baseline variability of <5 for 30-50 mins, or >25 for 15-25 mins
Variable decelerations with no concerning characteristics for 90 minutes or more.
Variable decelerations with any concerning characteristics in up to 50% of contractions for 30 minutes or more.
Variable decelerations with any concerning characteristics in over 50% of contractions for less than 30 minutes.
Late decelerations in over 50% of contractions for less than 30 minutes, with no maternal or fetal clinical risk factors such as vaginal bleeding or significant meconium
Abnormal features on CTG?
Baseline rate <100 or >180bpm
Baseline variability <5 for >50 mins, or >25 for >25 mins, or sinusoidal
Variable decelerations with any concerning characteristics in over 50% of contractions for 30 minutes (or less if any maternal or fetal clinical risk factors).
Late decelerations for 30 minutes (or less if any maternal or fetal clinical risk factors).
Acute bradycardia, or a single prolonged deceleration lasting 3 minutes or more.
What is the rule of 3s for foetal bradycardia on CTG?
If foetal bradycardia occurs for…
3 minutes – call for help
6 minutes – move to theatre
9 minutes – prepare for delivery
12 minutes – deliver the baby (by 15 minutes)
What is foetal blood sampling?
Taking a blood sample from the foetal scalp. Used alongside CTG during labour to assess the wellbeing of the foetus
It provides info on pH and lactate levels of foetal blood which can be used to assess if baby is recieving enough oxygen
Signs of labour?
Regular and painful uterine contractions
a show (shedding of mucous plug from cervix)
rupture of the membranes (not always)
shortening and dilation of the cervix on examination
3 stages of labour:
stage 1: from the onset of true labour to when the cervix is fully dilated to 10cm
stage 2: from full dilation to delivery of the fetus
stage 3: from delivery of fetus to when the placenta and membranes have been completely delivered
Monitoring in labour?
Foetal HR monitored every 15min or continuously via CTG
Contractions assessed every 30min
Maternal pulse rate assessed every 60min
Maternal BP and temp should be checked every 4 hours
Vaginal exam should be offered every 4 hours to check progression of labour
Maternal urine should be checked for ketones and protein every 4 hours
How long does stage 1 of labour usually last?
Primigravida - 8-18 hours
Multigravida - 5-12 hours
What are the 2 phases of stage 1 of labour?
Latent phase = 0-4cm dilation - uusally progressed at 0.5cm per hour. Irregular contractions with some cervical changes e..g. effacement
Active phase = 4-10cm - 1cm/hour. Regular contractions
What are Braxton-Hicks contractions?
Occasional irregular contractions of the uterus usually felt during the second and third trimester where women experience temporary and irregular tightening or mild cramping in the abdomen
They do not indicate the onset of labour and they do not progress or become regular
Staying hydrated and relaxed can help reduce them
What is vertex positioning of the foetus and how common is it for babies to be in this position at the point of established labour?
Cephalic position with neck tucked in
90%
What are the 2 phases of second stage of labour?
Passive second stage - 2nd stage i.e. cervix fully dilated in absence of pushing
Active stage - 2nd stage with active maternal pushing
What is cervical ripening?
Also known as cervical effacement
The softening, thinning and shortening of the cervix that occurs before labour and allows the cervix to dilate
Oestrogen, relaxin and prostaglandins break down cervical connective tissue
Outline the role of oxytocin in initiating labour?
Throughout pregnancy oxytocin has limited action as there are low numbers of oxytocin receptrs and its inhibited by relaxin and progesterone
At around 36/40, under the influence of oestrogen there is an increase in the number of oxytocin receptors present within the myometrium so the uterine begins to respond to the pulsation release of oxytocin from the posterior pituitary gland by contracting = pushes baby towards cervix and its head pushes against the cervix
Oxytocin production is increased by afferent impulses from the cervix and vagina = positive feedback loop to release more oxytocin leading to stronger contractions
This is the Ferguson reflex
What happens in the passive phase of the second stage of labour?
The head of the foetus descends to the pelvic floor when the woman will then experience the desire to push
Outline foetal station?
This refers to where the presenting part is in the pelvis
Stations range from -5 to +5
0 means head is aligned with ischial spines
-5 means baby’s head is not yet engaged in the birth canal
+5 is when the head is crowning i.e. 5cm below ischial spines
Outline how the myometrium is specially adapted to drive the process of labour?
The fibres of the myometrium dont fully relax following each contraction
This steadily reduces the uterine capacity so the pressure inside becomes stronger as labour progresses and this helps with the expulsion of the foetus
Which hormones help make contractions more forceful and frequent during the active stage of labour?
Prostaglandins - more intracellular calcium is released per action potential, increasing the force of contractions
Oxytocin - lowers the threshold for action potentials, increasing the frequency of contractions
How long does the active phase of the second stage of labour typically take?
<1 hour in nulliparous women
About 20 mins in multiparous women
If active phase of second stage of labour lasts >1 hour what should be considered?
Ventouse extraction, forceps delivery of caesarean section
Outline delivery of the foetus?
Once the head of the foetus reaches the perineum, it extends in order to come up and out of the pelvis. Following delivery of the head, it rotates by 90 degrees to assist with delivery of the shoulders.
The anterior shoulder delivers first, coming under the symphysis pubis while the body flexes laterally and posteriorly to aid passage. Following this the body flexes laterally and anteriorly to help deliver the posterior shoulder.
Once the shoulders have been delivered the rest of the body follows.
Describe pelvic dimensions?
Transverse diameter - pelvic inlet is largest 13cm
Anterior-posterior diameter - pelvic outlet is largest 13cm
Since transverse diameter is > AP diameter in pelvic inlet, the widest circumference of the foetal head descends in a transverse position. However when it gets closer to the pelvic outlet, the nature of the pelvic floor muscles encourages the foetal head to rotate from a transverse to AP position as this is greater
Explain how fetal head diameter varies depending upon the degree of neck flexion
Suboccipitobregmatic (vertex, flexed) is 9.5cm
Occipitofrontal (vertex, neutral flexion) is 11.0cm
Submentobregmatic (face) is 9.5cm
Verticomental (brow) is 13.5cm - largest and most challenging
Outline foetal cardinal movements
Descent - foetus descends into pelvis from 38 weeks in primigravida women or may not occur until labour in multigravida women
Engagement - when the largest diameter of the foetal head descends deep into the maternal pelvis. Defines on abdominal palpation where foetal head is 3/5th palpable or less
Flexion - occiput comes into contact with pelvic floor which causes flexion of the foetal neck. This allows circumference of foetal head to reduce to sub-occpitobregmatic 9.5cm which is the smallest diameter
Internal rotation - foetal head completes 90 degree turn
Crowning - when the widest diameter of the foetal head successfully negotiates through the narrowest part of the maternal bony pelvis. Clinically evidence when the head visible at the vulva, no longer retreats between contractions. Pushing must now be controlled so head is born with control so that skin and muscles in perineum have time to stretch.
Extension - occiput slips beneath the suprapubic arch allowing head to extend. Foetus born with its occiput anterior
External rotation/restitution - head naturally aligns with the shoulders. Shoulders reach the pelvic floor and complete their rotation from a transverse to AP position
Delivery of shoulder and body = expulsion
What encourages foetal descent in the pelvis?
Increased abdominal muscle tone
Braxton hicks in the late stages of pregnancy
Fundal dominance of the uterine contractions during labour
Increased frequency and strength of contractions during labour
What is the third stage of labour?
This follows delivery and lasts until placenta is delivered
Uterine muscle fibres contract to compress blood vessels supplying the placenta which then shears away from the uterine wall. Contractions continue until placenta and membranes have been delivered.
This stage usually lasts about 15mins and up to 500ml blood loss is normal
What is a partogram?
Pre-printed paper form on which labour observations are recorded
It monitors the progress of labour and can identify cases of abnormal labour where intervention may be necessary
What are the 2 ways of managing the 3rd stage of labour?
Active - IM injection of oxytocin as soon as you give birth to make womb contract. The cord is clamped and cut within 5 minutes or birth and then controlled cord traction of the umbilical cord during uterine contraction occurs to help deliver the placenta. The other hand will press on the uterus upwards to prevent uterine prolapse. After the uterus is massaged until it is contracted and firm and the placenta will be examined to ensure it is complete and no tissue remains in the uterus.
Physiological - natural. Cord is not cut until it has stopped pulsing which takes 2-4 minutes. Placenta comes away from womb and you can push the placenta out in a few minutes
What are the benefits and problems with active management of the third stage of labour?
It shortens the third stage, reduces the risk of postpartum haemorrhage. Will be initiated if there is any haemorrhage or a prolonged third stage (>60 mins)
Associated with nausea, vomiting and abdominal cramping
How commonly is induction of labour required?
In 20% of pregnancies
Indications for induction of labour?
prolonged pregnancy, e.g. 1-2 weeks after the estimated date of delivery
prelabour premature rupture of the membranes
maternal medical problems e.g. diabetic mother > 38 weeks, pre-eclampsia, obstetric cholestasis
intrauterine fetal death
What is the Bishop score?
Outline it
A scoring system used to determine whether to induce labour
It scores the following from 0-3 (position and consistency score 0-2)
Cervical position
Cervical consistency
Cervical effacement
Cervical dilation
Foetal station
Score <5 means labour is unlikely to start without induction
Score >=8 indicates cervix is ripe and high change of spontaneous labour
Possible options for induction of labour
Membrane sweep
Vaginal prostaglandin E2
Oral prostaglandin E2
Maternal oxytocin infusion
Amniotomy
Cervical ripening balloon
