Labour and delivery Flashcards
What are the 3 stages of labour?
First stage - from the onset of labour (true contractions) until 10cm cervical dilatation
Second stage - from 10cm cervical dilatation until delivery of the baby
Third stage - from delivery of the baby until delivery of the placenta
What are the 3 phases of stage 1 labour?
involves cervical dilation and effacement (getting thinner).
The “show = mucus plug in the cervix, which prevents bacteria from entering the uterus during pregnancy, falling out and creating space for the baby to pass through
Latent phase - from 0 to 3cm dilation of the cervix. This progresses at around 0.5cm per hour. There are irregular contractions.
Active phase - from 3cm to 7cm dilation of the cervix. This progresses at around 1cm per hour, and there are regular contractions.
Transition phase - from 7cm to 10cm dilation of the cervix. This progresses at around 1cm per hour, and there are strong and regular contractions.
4 signs of labour
Show (mucus plug from the cervix)
Rupture of membranes
Regular, painful contractions
Dilating cervix on examination
difference between latent 1st stage and established 1st stage of labour
The latent first stage is when there are both:
Painful contractions
Changes to the cervix, with effacement and dilation up to 4cm
The established first stage of labour is when there are both:
Regular, painful contractions
Dilatation of the cervix from 4cm onwards
3 classes of prematurity
Under 28 weeks: extreme preterm
28 - 32 weeks: very preterm
32 - 37 weeks: moderate to late preterm
Babies are considered non-viable below 23 weeks gestation
Jesus baby if ≥24 weeks
how can you prevent preterm labour
vaginal progesterone
cervical cerclage - stich in cervix
how is vaginal progesterone useful to prevent preterm labour?
role: maintain pregnancy and prevent labour by decreasing activity of the myometrium and prevent the cervix remodelling in preparation for delivery.
This is offered to women with a cervical length <25mm on vaginal US 16-24 weeks
how is cervical cerclage useful to prevent preterm labour?
stitch in cervix to add support, keep it closed
under GA or spinal
remove stitch when in labour or reaches term
This is offered to women with a cervical length <25mm on vaginal US 16-24 weeks WHO HAVE had previous pre-term birth or cervical trauma (colposcopy, cone biopsy)
“Rescue” cervical cerclage may also be offered between 16- 27 + 6 weeks when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery.
how do you if woman has ruptured her membranes (amniotic sac)?
speculum –>pooling of amniotic fluid in the vagina. No tests are required.
If doubt:
- Insulin-like growth factor-binding protein-1 (IGFBP-1) = a protein present in high conc in amniotic fluid, which can be tested on vaginal fluid
- Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
how do you manage PPROM?
Preterm prelabour rupture of membranes is where the amniotic sac ruptures, releasing amniotic fluid, before the onset of labour and in a preterm pregnancy
Prophylactic antibiotics –> prevent chorioamnionitis.
- erythromycin 250mg TDS for 10/7 or until labour is established (if within 10 days)
Induction of labour may be offered from 34 weeks
what is fetal fibronectin used to diagnose?
Preterm labour
alternative test to vaginal ultrasound.
Fetal fibronectin is the “glue” between the chorion and the uterus, and is found in the vagina during labour.
<50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
5 methods of improving outcomes in preterm labour
- Fetal monitoring (CTG or intermittent auscultation)
- Tocolysis with nifedipine: nifedipine is a CCB that suppresses labour
- Maternal corticosteroids: can be offered <35 weeks gestation to reduce neonatal morbidity and mortality
- IV magnesium sulphate: can be given <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
what medication causes tocolysis?
nifedipine - CCB
used to stop uterine contractions
aosiban = oxytocin R antagonist, for when if is CI
when can tocolysis be used?
used to stop uterine contractions (Pre-term)
used 24-34 weeks in preterm labour to delay delivery
only use <48 hours
also administer maternal steroids, transfer to specialist unit with NICU
why are maternal steroids given in premature labour?
helps to develop the fetal lungs and reduce respiratory distress syndrome after delivery.
used <36 weeks gestation.
regime: 2 doses IM
betamethasone, 24 hours apart.
Why is IV MAGNESIUM SULFATE given to mother in premature labour?
protects fatal brain in premature delivery
dec risk and severity of cerebral palsy
give within 24 hours of delivery of PTB <34 weeks
give a bolus, then infusion for 24 hours or until birth
how do you monitor for magnesium toxicity in treatment of PTB?
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
when is induction of labour offered?
41 - 42 weeks
Prelabour rupture of membranes Fetal growth restriction Pre-eclampsia Obstetric cholestasis Existing diabetes Intrauterine fetal death
What is the Bishop score?
used to determine wether to induce labour
min score 0 ,max 13
<8 suggests cervical ripening may be req to prepare cervix
what 5 things are assessed on bishop score?
5 things are assessed and given a score based on different criteria (minimum score is 0 and maximum is 13):
Fetal station (scored 0 - 3) Cervical position (scored 0 - 2) Cervical dilatation (scored 0 - 3) Cervical effacement (scored 0 - 3) Cervical consistency (scored 0 - 2)
A score of ≥ 8 predicts a successful induction of labour.
<8 suggests cervical ripening may be required to prepare the cervix.
5 options to induce labour
- membrane sweep (adjunct only)
- vaginal prostaglandins
- cervical ripening balloon CRB
- artificial rupture of membranes with oxytocin infusion
- oral mifepristone + misoprostol (intrauterine fetal death)
what 2 things do you monitor when induce labour?
Cardiotocography (CTG) to assess the fetal heart rate and uterine contractions before and during induction of labour
Bishop score before and during induction of labour to monitor the progress
what is the main complication of induction of labour?
uterine hyperstimulation
- contraction of the uterus is prolonged and frequent –> causes fetal distress and compromise.
2 criteria for uterine hyperstimulation
- Individual uterine contractions lasting > 2 minutes in duration
- > 5 uterine contractions every 10 minutes
3 consequences of uterine hyperstimulation
- Fetal compromise, with hypoxia and acidosis
- Emergency caesarean section
- Uterine rupture
management of uterine hyperstimulation
Removing the vaginal prostaglandins, or stopping the oxytocin infusion
Tocolysis with terbutaline
Indications for Continuous CTG Monitoring in labour
Sepsis Maternal tachycardia (> 120) Significant meconium Pre-eclampsia (particularly blood pressure > 160 / 110) Fresh antepartum haemorrhage Delay in labour Use of oxytocin Disproportionate maternal pain
5 key features on 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 is a good sign on CTG?
Accelerations (periods where the fetal heart rate spikes) are generally a good sign that the fetus is healthy, particularly when occurring alongside contractions of the uterus
3 words to classify baseline rate and variability on CTG
reassuring, non-reassuring and abnormal
BLR reassuring 110-160
VAR reassuring 5-25
what is a concerning sign on CTG?
decelerations
fetal HR drops in response to hypoxia (to save O2 for vital organs)
4 types: Early decelerations Late decelerations Variable decelerations Prolonged decelerations
what are Early decelerations on CTG?
gradual dips and recoveries in HR, correspond with uterine contractions.
lowest point of the declaration corresponds to the peak of the contraction.
Normal, not pathological.
Caused by the uterus compressing the head of the fetus –> stimulae the vagus nerve of the fetus, slowing the heart rate.
what are late decelerations on CTG?
gradual falls in HR that starts after the uterine contraction has already begun –> delay btw the uterine contraction and the deceleration.
The lowest point of the declaration occurs after the peak of the contraction.
Late decelerations are caused by hypoxia in the fetus, and are a more concerning finding.
They may be caused by: - excessive uterine contractions,
- maternal hypotension
- maternal hypoxia.
what are variable decelerations on CTG?
abrupt decelerations that may be unrelated to uterine contractions. Fall >15 BPM from the baseline.
The lowest point of the declaration occurs within 30 seconds, and the deceleration lasts < 2mins in total.
- often indicate intermittent compression of the umbilical cord, –> causing fetal hypoxia.
Brief accelerations before and after the deceleration are known as shoulders, and are a reassuring sign that the fetus is coping.
what are prolonged decelerations on CTG?
Last between 2 and 10 minutes with a drop of more than 15 bpm from baseline.
This often indicates compression of the umbilical cord, causing fetal hypoxia.
These are abnormal and concerning.
when is a CTG reassuring?
- no decelerations
- early decelerations
- less than 90 mins of variable decelerations
with no concerning features
Regular variable decelerations and late decelerations are classed as non-reassuring or abnormal, depending on the features. Prolonged decelerations are always abnormal.
what are the 4 categories for CTG?
- 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
what’s the rule of 3s for metal bradycardia?
3 minutes - call for help
6 minutes - move to theatre
9 minutes - prepare for delivery
12 minutes - deliver the baby (by 15 minutes)
sinusoidal CTG
sine wave pattern
assoc with severe fatal anaemia
- bc vasa praevia with fatal haemorrhage
DR C BRaVADO for CTG
DR C BRaVADO is a mnemonic often taught to assess the features of a CTG in a structured way. It involves assessing in order:
DR - Define Risk (define the risk based on the individual woman and pregnancy before assessing the CTG)
C - Contractions
BRa - Baseline Rate
V - Variability
A - Accelerations
D - Decelerations
O - Overall impression (given an overall impression of the CTG and clinical picture)
If you are asked to assess a CTG in your exams, use the DR C BRaVADO structure to describe each feature in turn. Give an overall impression of the CTG as being normal (all features are reassuring), suspicious, pathological, or need for urgent intervention, as described in the NICE guidelines (2017).
what is cord prolapse?
when the umbilical cord descends below the presenting part of the fetus and through the cervix into the vagina, after rupture of the fetal membranes.
There is a significant danger of the presenting part compressing the cord, resulting in fetal hypoxia.
risk factors for cord prolapse?
- abnormal lie >37 weeks
= unstable, transverse or oblique
–> space for cord to prolapse
(in cephalic lie, no room for cord to descend)
diagnosis of cord prolapse?
signs of fetal distress on CTG
vaginal exam or speculum
management of cord prolapse
relieve pressure on cord
- knee-chest position (all 4s) or lie in left lateral position
totolytics (terbutaline) to minimise contractions
emergency C-section
do not push cord back in
keep cord warm and wet, minimal handling (causes vasospasm)
what medication do you give after instrumental delivery?
1 dose co-amoxiclav
indications for instrumental delivery
Failure to progress
Fetal distress
Maternal exhaustion
Control of the head in various fetal positions
also inc risk of needing instrumental delivery when epidural used
risks of instrumental delivery to mother
Postpartum haemorrhage Episiotomy Perineal tears Injury to the anal sphincter Incontinence of the bladder or bowel Nerve injury (obturator or femoral nerve)
risks of instrumental delivery to baby
The key risks to remember to the baby are:
Cephalohaematoma with ventouse
Facial nerve palsy with forceps (also fat necrosis, resolves)
Rarely there can be serious risks to the baby: Subgaleal haemorrhage (most dangerous) Intracranial haemorrhage Skull fracture Spinal cord injury
what nerve injuries can mother get on instrumental delivery?
rare, resolves over 6-8 weeks
Femoral N
- may be compressed against the inguinal canal during a forceps delivery.
- Injury –> weakness of knee extension, loss of the patella reflex and numbness of the anterior thigh and medial lower leg.
Obturator nerve
- may be compressed by forceps or by the fetal head during NVD
- Injury –> weakness of hip adduction and rotation, and numbness of the medial thigh.
3 nerve injuries in birth (usually unrelated to instrumental delivery)
lateral cutaneous nerve of the thigh
- runs under the inguinal ligament.
- Prolonged flexion at the hip while in the lithotomy position can result in injury
- -> numbness of the anterolateral thigh.
The lumbosacral plexus
- may be compressed by the fetal head during the 2nd stage of labour.
- Injury –> foot drop and numbness of the anterolateral thigh, lower leg and foot.
The common peroneal nerve
- may be compressed on the head of the fibula whilst in the lithotomy position.
- Injury –> foot drop and numbness in the lateral lower leg.
risk factors for perineal tear
Perineal tears are more common with: First births (nulliparity) Large babies (over 4kg) Shoulder dystocia Asian ethnicity Occipito-posterior position Instrumental deliveries
4 degrees of perineal tear
each involving injury to tissue beyond the previous:
First-degree - injury limited to the frenulum of the labia minora (where they meet posteriorly) and superficial skin
Second-degree - including the perineal muscles, but not affecting the anal sphincter
Third-degree - including the anal sphincter, but not affecting the rectal mucosa
Fourth-degree - including the rectal mucosa
Third-degree tears can be subcategorised as:
3A - less than 50% of the external anal sphincter affected
3B - more than 50% of the external anal sphincter affected
3C - external and internal anal sphincter affected
what are the 2 options for management of the 3rd stage of labour?
physiological - placenta delivered by maternal effort (no meds or cord traction)
or
active - assisted
how can you actively manage 3rd stage labour?
- IM oxytocin (10 IU) –> contracts uterus
cord clamped and cut within 5 mins of birth (wait 1-3 mins before clamp unless baby needs resus)
palpate abdo for uterine contractions
- controlled cord traction during contractions
- 1 hand presses uterus upwards –> prevent uterine prolapse
Aim: deliver placenta in 1 piece
massage uterus until contracted and firm
examine placenta to ensure complete and no tissue remains
shortens 3rd stage, dec risk of bleeding
assoc with nausea and vomiting
when is active management of 3rd stage labour initiated?
routinely offered to all women to reduce the risk of PPH
Also if:
Haemorrhage
>60-minute delay in delivery of the placenta (prolonged third stage)
criteria for PPH
500ml after vaginal delivery
1000ml after C-section
minor or major PPH
Minor PPH - under 1000ml blood loss
Major PPH - over 1000ml blood loss
Major PPH can be further sub-classified as:
Moderate PPH - 1000 - 2000ml blood loss
Severe PPH - over 2000ml blood loss
primary or secondary PPH
Primary PPH: bleeding within 24 hours of birth
Secondary PPH: from 24 hours to 12 weeks after birth
four T’s for PPH causes
T - Tone (uterine atony - the most common cause)
T - Trauma (e.g. perineal tear)
T - Tissue (retained placenta)
T - Thrombin (bleeding disorder)
mechanical management of PPH
Rubbing the uterus through the abdomen to stimulates a uterine contraction (referred to as “rubbing up the fundus”)
Catheterisation (bladder distention prevents uterus contractions)
medical management of PPH
Oxytocin (slow injection followed by continuous infusion) (infuse 40 units in 500mls)
Ergometrine IV or IM stimulates smooth muscle contraction (contraindicated in hypertension)
Carboprost (IM) is a prostaglandin analogue and stimulates uterine contraction (caution in asthma)
Misoprostol (sublingual) is also a prostaglandin analogue and stimulates uterine contraction
Tranexamic acid (IV) is an antifibrinolytic that reduces bleeding
surgical management of PPH
Intrauterine balloon tamponade - inserting an inflatable balloon into the uterus to press against the bleeding
B-Lynch suture - putting a suture around the uterus to compress it
Uterine artery ligation - ligation of one or more of the arteries supplying the uterus to reduce the blood flow
Hysterectomy is the “last resort” but will stop the bleeding and may save the woman’s life
most common cause of secondary PPH
RPOC or infection (endometritis)
investigation and management of secondary PPH
Investigations involve:
Ultrasound for retained products of conception
Endocervical and high vaginal swabs for infection
Management depends on the cause:
Surgical evacuation of retained products of conception
Antibiotics for infection
4 categories of emergency C-section
Category 1: There is an immediate threat to the life of the mother or baby. Decision to delivery time is 30 minutes.
Category 2: There is not an imminent threat to life, but caesarean is required urgently due to compromise of the mother or baby. Decision to delivery time is 75 minutes.
Category 3: Delivery is required, but mother and baby are stable.
Category 4: This is an elective caesarean,
2 possible incisions for C-section
Pfannenstiel incision is a curved incision two fingers width above the pubic symphysis
Joel-cohen incision is a straight incision that is slightly higher (this is the recommended incision)
risks of spinal or general anaesthetic
Allergic reactions or anaphylaxis Hypotension Headache Urinary retention Nerve damage (spinal anaesthetic) Haematoma (spinal anaesthetic) Sore throat (general anaesthetic) Damage to the teeth or mouth (general anaesthetic)
4 measures to reduce the risks during caesarean section
- H2 receptor antagonists (e.g. ranitidine) or PPI(e.g. omeprazole) before the procedure
- -> risk of aspiration penumonitis caused by acid reflux from prolonged period lying flat - Prophylactic antibiotics during the procedure to reduce the risk of infection
- Oxytocin during the procedure to reduce the risk of PPH
- VTE prophylaxis with LMWH
2 key causes of sepsis in pregnancy
chorioamnionitis - MC
UTI
3 signs of chorioamnionitis
Abdominal pain
Uterine tenderness
Vaginal discharge
with sepsis signs
what is an amniotic fluid embolism?
amniotic fluid into mom’s blood (in labour and delivery)
contains fetal tissue –> immune reaction bc foreign –> systemic illness, more similar to anaphylaxis than VTE
20% mortality rate
presents like sepsis, PE, anaphylaxis
manage ABCDE, supportive
The main risk factors for amniotic fluid embolus
Increasing maternal age
Induction of labour
Caesarean section
Multiple pregnancy
difference between in/complete uterine rupture
comp of labour, myometrium ruptures
incomplete or uterine dehiscene
- uterine serosa (perimetrium) surrounding the uterus remains intact.
complete
- serosa ruptures with myometrium
–> contents into peritoneal cavity
baby into cavity, lots of bleeding
risk factors for uterine rupture
main: previous C-section –> scar is point of weakness, may rupture with xc pressure (oxytocin stem)
Vaginal birth after caesarean (VBAC) Previous uterine surgery Increased BMI High parity Increased age Induction of labour Use of oxytocin to stimulate contractions
(rare if 1st birth)
presentation of uterine rupture
acutely unwell mom + abnormal CTG
Ceasing of uterine contractions!! Abdominal pain Vaginal bleeding Hypotension Tachycardia Collapse
management of uterine rupture
Resuscitation and transfusion may be required.
Emergency caesarean section is necessary to remove the baby, stop any bleeding and repair or remove the uterus (hysterectomy).
the 3 P’s that influence progress in labour
Power (uterine contractions)
Passenger (size, presentation and position of the baby)
Passage (the shape and size of the pelvis and soft tissues)
Psyche can be added as a fourth P, referring to the support and antenatal preparation for labour and delivery.
consider delayed 1st stage of labour when
Less than 2cm of cervical dilatation in 4 hours
Slowing of progress in a multiparous women
when is a partogram used?
Women are monitored for their progress in the first stage of labour using a partogram.
what is recorded on a partogram?
Cervical dilatation (measured by a 4-hourly vaginal examination)
Descent of the fetal head (in relation to the ischial spines)
Maternal pulse, blood pressure, temperature and urine output
Fetal heart rate
Frequency of contractions
Status of the membranes, presence of liquor and whether the liquor is stained by blood or meconium
Drugs and fluids that have been given
how can you tell if labour progressing on a partogram?
2 lines labelled alert and action
plot cervix dilation against duration of labour
if cross to right, too slow
Cross alert line –> indication for amniotomy (artificially ROM) and a repeat examination in 2 hours.
Cross action line –> escalate care
what is a delayed 2nd stage labour?
when the active second stage (pushing) lasts over:
2 hours in a nulliparous woman
1 hour in a multiparous woman
what does attitude of foetus mean?
refers to the posture of the fetus.
For example, how the back is rounded and how the head and limbs are flexed.
3 types of breech presentation
Breech presentation - the legs are first. This can be:
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
how can you stimulate contractions during labour?
oxytocin - 1st line
It is started at a low rate and titrated up at intervals of at least 30 minutes as required. The aim is for 4 - 5 contractions per 10 minutes.
monitor fetus
