Labour Flashcards
Define labour.
The presence of strong, regular, painful contractions resulting in progressive cervical change
What is the first stage of labour? How long does it last?
- Begins with the onset of contractions and ends with full cervical dilatation (10cm)
- Average duration (in nulliparous women) = 8 hours
How do we divide the first stage of labour?
- Latent phase
- Begins with the onset of contractions and ends with 3-4cm cervical dilatation and full effacement
- Active phase
- Begins with 3-4cm cervical dilatation and ends with full (10cm) cervical dilatation
- Normal progress = cervical dilatation of at least 1cm every 2 hours
- Abnormal progress = cervical dilatation of <2cm in 4 hours
Describe the 2nd stage of labour
Begins with full cervical dilatation (10cm) and ends with the birth of the baby
How do we divide the second stage of labour?
- Passive phase
- Begins with full dilatation until head reaches pelvic floor and ends with the onset of involuntary expulsive contractions
• I.e. there is no maternal urge to push
- Begins with full dilatation until head reaches pelvic floor and ends with the onset of involuntary expulsive contractions
- Active phase
- Begins with the onset of involuntary expulsive contractions and ends with the birth of the baby
- I.e. there is maternal urge to push
- Prolonged = lasting >2 hours in a nulliparous woman, or >1 hour in a multiparous woman (allow an extra hour if the woman has an epidural)
- Begins with the onset of involuntary expulsive contractions and ends with the birth of the baby
Define the third stage of labour. How long does it last?
Begins with the birth of the baby and ends with complete delivery of the placenta and membranes
Average duration = 5-10 mins
How do we manage the 3rd stage of labour?
- Physiological
- Where the placenta is delivered by maternal effort
- Associated with heavier bleeding
- Prolonged = lasting >60mins
- Active
- Recommended to all women
- Involves administering 10 iU oxytocin IM to the mother (with the birth of the anterior shoulder or immediately after delivery)
- Reduces incidence of PPH (from 15% → 5%)
- Prolonged = lasting >30mins
Describe the mechanism of labour.
- Engagement
- Descent
- Flexion
- Internal rotation
- Crowning
- Extension
- Restitution
- External rotation
- Delivery of the shoulders and foetal body
What monitoring is needed during the 1st stage of labour?
o Every 15 mins – foetal HR (or continuous CTG if indicated)
o Every 30 mins – frequency of contractions
o Every 1 hour – maternal HR
o Every 4 hours – maternal BP, temperature and vaginal examination
o Document volume of urine passed, and test for ketones and protein
What monitoring is needed during the 2nd stage of labour?
o Every 5 mins – foetal HR (or continuous CTG if indicated)
o Every 30 mins – frequency of contractions
o Every 1 hour – maternal HR, BP and vaginal examination
o Document volume of urine passed, and test for ketones and protein
What monitoring is needed during the 3rd stage of labour?
o Monitor maternal observations for at least 2 hours
o Document volume of vaginal blood loss
o Examine the delivered placenta for completeness
o Inspect the vulva for evidence of tears
What is the immediate care of the newborn?
- The baby will usually take its first breath within seconds
- After clamping and cutting the umbilical cord, the baby should have an Apgar score calculated at 1 minute of age and then repeated again at 5 minutes and 10 minutes.
- A score of 0-3 is very low score, between 4-6 is moderate low and between 7 - 10 means the baby is in a good state.
- Encourage skin-to-skin contact between mother and baby as soon as possible after birth
- Dry and cover the baby with a warm blanket or towel, maintaining this contact
- Encourage initiation of breastfeeding within the first 1 hour
- Routine measurements of newborn head circumference, birthweight and temperature should
- be measured soon after this hour
- Administer the first dose of vitamin K to the baby in the delivery room
- Attach a wrist label to the baby for identification
What are the indications of induction of labour?
- Hypertensive disorders
- Prolonged pregnancy
- Compromised fetus e.g. growth restriction
- Maternal diabetes
- Rhesus sensitisation
Other
- Fetal abnormality or death
- Social - may be requested
What does the BISHOP score show?
Accepted method of recording the ripeness of the cervix before labour. It takes account of the length, dilation, consistency of the cervix and the level of the fetal head.
What are the bishop cut-off scores?
High scores (≥8) = favourable cervix meaning there is a high chance of spontaneous labour, or response to interventions made to induce labour.
Low scores (≤6) = induction needed to start labour.
How do we calculate the BISHOP score?
What are the different methods of induction?
- Membrane sweeping
- Vaginal Prostaglandin E2
- Mechanical induction to break waters
- Artificial rupture of membranes aka Amniotomy
- IV syntocinon
When should membrane sweeping be offered?
Often offered prior to formal induction to prevent prolongation of pregnancies
Offered weekly from 40 weeks gestation in a nulliparous woman (or 41 weeks gestation in a multiparous woman)
Describe the process of membrane sweeping. What happens in response?
Involves the insertion of a gloved finger through the cervix and its rotation around the inner rim of the cervix
• Only possible if the cervix is beginning to dilate and efface
Releases physiological prostaglandins, stimulating effacements, and moves membranes away from the cervical os
Describe the process of membrane sweeping. What happens in response?
Involves the insertion of a gloved finger through the cervix and its rotation around the inner rim of the cervix
• Only possible if the cervix is beginning to dilate and efface
Releases physiological prostaglandins, stimulating effacements, and moves membranes away from the cervical os
What must be excluded before membrane sweeping?
Placenta praevia
What is the first line methods of induction?
Vaginal Prostaglandin E2
How is vaginal prostaglandin administered? What is the risk associated with it?
Can be administered as a vaginal tablet, vaginal gel or pessary
o Tablet or Gel (Prostin®) : 1 dose, followed by a 2nd dose after 6 hours (max: 2 doses)
o Pessary (Propess®) 1 dose over 24 hours
o Risk of uterine hyperstimulation
Describe the purpose of mechanical induction to break waters.
- In times of Covid, they started using Mechanical induction to break waters = a catheter is inserted into the cervix which has a small balloon that can be filled with water; commonly referred to as a cervical ripening balloon (CRB).
- This is just as effective but preferred to Vaginal prostaglandin as this avoids risk of uterine hyperstimulation, and is considered safer for baby.
When should an artificial rupture of membranes be arranged? When should it be avoided and what is the risk?
Artificial Rupture of Membranes (ARM) aka Amniotomy
- Should not be used first-line for induction
- Only possible if the cervix is beginning to dilate and efface
- Avoid if the presenting part is mobile or high
- Risk of umbilical cord prolapse
- (Can also be used to augment or accelerate labour)
When should IV syntocinon be offered? What is the risk?
- Should not be used first-line for induction
- Offered if 2 hours after membranes have ruptured, labour has not ensued
- To increase uterine contractions, until 3-4 contractions are achieved every 10mins
- Risk: uterine hyperstimulation, ↑ risk of uterine rupture (esp. in VBAC or previous uterine myomectomy)
- (Can also be used to augment or accelerate labour)
Summarise induction of labour. And what would happen if it failed.
- Induction:
- Membrane sweep to stimulate physiological prostaglandins
- Vaginal PGE2 or Mechanical balloon
- If still no ROM, then ARM
- After 2hrs of ARM, start IV Syntocinon
- If induction fails:
- Rest period followed by attempting induction again (only if there is no major threat to foetal or maternal condition)
- C-section
What would you use to induce labour following intrauterine foetal death?
Mifepristone (anti-progesterone) and misoprostol (prostaglandin)
Often used to induce labour following intrauterine foetal death when you would give vaginal prostaglandins.
Define breech presentation. What increases the risk of breech?
Breech presentation refers to when the presenting part of the fetus (the lowest part) is the legs and bottom.
- nulliparity
- low-lying placenta, placenta praevia
- polyhydramnios
- multiple pregnancy
*
How common is breech presentation?
- 1 in 4 breech at 28 weeks
- 3-5% still breech at term (37 weeks gestation)
What are the types of breech?
- Complete breech (full breech), where the legs are fully flexed at the hips and knees
- Extended breech (frank breech) with both legs flexed at the hip and extended at the knee
- Footling breech, with a foot is presenting through the cervix with the leg extended
- Incomplete breech, with one leg flexed at the hip and extended at the knee
Define external cephalic version,
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
When is external cephalic version performed? What is the success rate?
Performed at 36 weeks if nulliparous, or 37 weeks if multiparous
50% success rate
What are the contra-indications of ECV?
- Where C-section delivery is required (irrespective of ECV outcome)
- Abnormal CTG
- Major uterine anomaly
- Recent antepartum haemorrhage (last 7 days)
- Ruptured membranes
- Multiple pregnancy
Describe the process of ECV.
- Women are given tocolysis to relax the uterus before the procedure.
- Tocolysis is with subcutaneous terbutaline. Terbutaline is a beta-agonist similar to salbutamol.
- It reduces the contractility of the myometrium, making it easier for the baby to turn.
- Rhesus-D negative women require anti-D prophylaxis when ECV is performed.
- A Kleihauer test is used to quantify how much fetal blood is mixed with the maternal blood, to determine the dose of anti-D that is required.
What are the options if the baby is still breech at term? Explain the contraindications
- planned caesarian section
- planned breech vaginal birth
- footling breech
- baby is larger or smaller than average
- baby is in a certain position, for example, if its neck is very tilted back (hyper extended)
- low-lying placenta (placenta praevia)
- you have pre-eclampsia or any other pregnancy problems;
Define prematurity.
Prematurity is defined as birth before 37 weeks gestation.
At what point onwards is resuscitation offered? Why not before this stage?
Babies are considered non-viable below 23 weeks gestation.
Generally, from 23 to 24 weeks, resuscitation is not considered in babies that do not show signs of life.
Babies born at 23 weeks have around a 10% chance of survival.
From 24 weeks onwards, there is an increased chance of survival, and full resuscitation is offered.
How do we classify prematurity?
- Under 28 weeks: extreme preterm
- 28 – 32 weeks: very preterm
- 32 – 37 weeks: moderate to late preterm
What are the clinical features of preterm labour?
- Regular or frequent sensations of abdominal tightening (contractions)
- Constant low, dull backache
- A sensation of pelvic or lower abdominal pressure
- Mild abdominal cramps
- Vaginal spotting or light bleeding
- Preterm rupture of membranes — in a gush or a continuous trickle of fluid after the membrane around the baby breaks or tears
- A change in type of vaginal discharge — watery, mucus-like or bloody
What are the RFs of preterm labour?
- Previous preterm labor or premature birth, particularly in the most recent pregnancy or in more than one previous pregnancy
- Pregnancy with twins, triplets or other multiples
- Shortened cervix
- Problems with the uterus or placenta
- Smoking cigarettes or using illicit drugs
- Certain infections, particularly of the amniotic fluid and lower genital tract
- Some chronic conditions, such as high blood pressure, diabetes, autoimmune disease and depression
- Stressful life events, such as the death of a loved one
- Too much amniotic fluid (polyhydramnios)
- Vaginal bleeding during pregnancy
- Presence of a fetal birth defect
- An interval of less than 12 months — or of more than 59 months — between pregnancies
- Age of mother, both young and older
- Black, non-Hispanic race and ethnicity
What are the complications of pre-term labour?
Neonatal
Intensive care
Cerebral palsy
Death
Chronic lung disease
Blindness
Minor disability
At 24 weeks: 1/3 handicapped, 1/3 die
Maternal
- Infection
- Severe illness
- Endometritis
- CS rate
How can we prevent pre-term labour? Who gets offered this?
- Vaginal Progesterone
- Cervical cerclage
Offer if:
- Hx of spontaneous preterm birth (<34 weeks) or mid-trimester loss (16+ weeks) AND
- TVUSS between 16-24 weeks show cervical length <25mm
When and who can vaginal progesterone be offered to? How is it given? How does it work?
- This is offered to women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation.
- Progesterone can be given vaginally via gel or pessary as prophylaxis for preterm labour
- Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery.
NICE: Offer to women who have
- a history of spontaneous preterm birth (up to 34+0 weeks of pregnancy) or mid-trimester loss (from 16+0 weeks of pregnancy onwards) or
- results from a transvaginal ultrasound scan carried out between 16+0 and 24+0 weeks of pregnancy that show a cervical length of 25 mm or less.
When using vaginal progesterone, start treatment between 16+0 and 24+0 weeks of pregnancy and continue until at least 34 weeks.
What is cervical cerclage, who is it offered to and when?
Cervical cerclage 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.
Cervical cerclage is offered to women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation, who have had a previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy).
“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.
If prophylactic cervical cerclage is used, ensure that a plan is in place for removal of the suture
Define 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).
How can you diagnose P-PROM?
Only if 30+ weeks - Offer a speculum examination to look for pooling of amniotic fluid and:
- if pooling of amniotic fluid is observed, do not perform any diagnostic test but offer care consistent with the woman having P‑PROM
- if pooling of amniotic fluid is not observed, perform an insulin-like growth factor binding protein‑1 test or placental alpha-microglobulin‑1 test of vaginal 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
If negative, explain to the woman that it is unlikely that she has P‑PROM, but that she should return if she has any further symptoms suggestive of P‑PROM or preterm labour
How to manage P-PROM?
- Prophylactic antibiotics
- Offer women with P‑PROM oral erythromycin 250 mg 4 times a day for a maximum of 10 days or until the woman is in established labour (whichever is sooner).
- For women with P‑PROM who cannot tolerate erythromycin or in whom erythromycin is contraindicated, consider an oral penicillin for a maximum of 10 days or until the woman is in established labour (whichever is sooner).
- Do not offer women with P‑PROM co‑amoxiclav as prophylaxis for intrauterine infection.
- Use a combination of clinical assessment and tests (C‑reactive protein, white blood cell count and measurement of fetal heart rate using cardiotocography) to diagnose intrauterine infection
- If the results of the clinical assessment or any of the tests are not consistent with each other, continue to observe the woman and consider repeating the tests.
- Offer maternal corticosteroids
- 1st line = IM betamethasone 24 mg 24 hours apart
- Women who have PPROM between 24+0 and 33+6 weeks’ gestation should be offered corticosteroids; steroids can be considered up to 35+6 weeks’ gestation.
- Offer IV magnesium sulphate
- 24hrs before delivery in 24+0 and 29+6 weeks of gestation
- DO NOT administer tocolytics - increased risk of infection
- Induction of labour may be offered from 34 weeks to initiate the onset of labour
• Intense clinical surveillance for signs of chorioamnionitis and pre-term labour
o There is a lack of consensus whether this is best inpatient or outpatient
o Within Imperial NHS trust, best practice is to admit until 28 weeks, after which 2- 3x/week outpatient monitoring until delivery
How do we diagnose premature labour with intact membranes?
Offer a clinical assessment to women reporting symptoms of preterm labour who have intact membranes. This should include:
- clinical history taking
- the observations described for the initial assessment of a woman in labour
- a speculum examination (followed by a digital vaginal examination if the extent of cervical dilatation cannot be assessed; be aware that if a swab for fetal fibronectin testing is anticipated -the swab should be taken before any digital vaginal examination.).
If the clinical assessment suggests that the woman is in suspected preterm labour and she is 29+6 weeks pregnant or less, advise treatment for preterm labour
If the clinical assessment suggests that the woman is in suspected preterm labour and she is 30+0 weeks pregnant or more, consider transvaginal ultrasound measurement of cervical length as a diagnostic test to determine likelihood of birth within 48 hours. Act on the results as follows:
- if cervical length is more than 15 mm, explain to the woman that it is unlikely that she is in preterm labour and:
- think about alternative diagnoses
- discuss with her the benefits and risks of going home compared with continued monitoring and treatment in hospital
- advise her that if she does decide to go home, she should return if symptoms suggestive of preterm labour persist or recur
- if cervical length is 15 mm or less, view the woman as being in diagnosed preterm labour and offer treatment
Consider fetal fibronectin testing as a diagnostic test to determine likelihood of birth within 48 hours for women who are 30+0 weeks pregnant or more if transvaginal ultrasound measurement of cervical length is indicated but is not available or not acceptable.
- if fetal fibronectin testing is negative (concentration 50 ng/ml or less), explain to the woman that it is unlikely that she is in preterm labour and: “ ”
- if fetal fibronectin testing is positive (concentration more than 50 ng/ml), view the woman as being in diagnosed preterm labour and offer treatment
If a woman in suspected preterm labour who is 30+0 weeks pregnant or more does not have transvaginal ultrasound measurement of cervical length or fetal fibronectin testing to exclude preterm labour, offer treatment consistent with her being in diagnosed preterm labour
Do not use transvaginal ultrasound measurement of cervical length and fetal fibronectin testing in combination to diagnose preterm labour.
How do we counsel on P-PROM?
What are the RFs for uterine rupture?
What are the RFs of shoulder dystocia?
Macrosomia
50% cases in babies >4kg
Previous shoulder dystocia
Increased Maternal BMI
Labour induction
Low height
Maternal DM
Instrumental delivery
How is shoulder dystocia recognised during delivery?
How should we manage shoulder dystocia?
- Lie woman flat and tell her to STOP pushing = as pushing can increase risk of foetal complications.
- Call for senior and neonatal help (press the emergency buzzer or 2222).
- External manoeuvres: the whole point is to increase the relative anterior-posterior diameter of the pelvis.
- McRobert’s manoeuvre – place patient with hips hyper-flexed and abducted (“thighs to abdomen, successful in 90% of cases).
- Suprapubic pressure – this is used to improve McRobert’s. You apply pressure down and forward to decrease the shoulder diameter.
- Consider episiotomy if this will make internal manoeuvres easier
- Internal manoeuvres: the whole point is to reduce the shoulder diameter by abducting the shoulder and allowing rotation into the wider oblique pelvis diameter.
- Rubin II manoeuvre – insert a hand behind the anterior shoulder and push it towards baby’s chest.
- Wood’s screw manoeuvre – Rubin 2 + insert second hand to apply pressure to front of posterior shoulder to aid further rotation.
- Deliver posterior arm – this reduces shoulder diameter by arm width. The baby’s wrist should be grasped, and the posterior arm should be gently tugged from the vagina in a straight line. Risk of humeral Fractures!
- Change position to all fours – this may help dislodge the anterior shoulder.
- Third-line manoeuvres should be considered very carefully to avoid unnecessary maternal morbidity and mortality, particularly by inexperienced practitioners: foetal cleidotomy, maternal symphisiotomy or Zavanelli (vaginal replacement of the foetal head followed by a CS – this can be used in bilateral shoulder dystocia)
How should a major PPH be managed?
- Call for senior help and initiate major obstetric haemorrhage MOH protocol (obstetric consultant, anaesthetic team, haematologist and blood transfusion lab)
-
ABCDE approach
- Position the patient flat
- 2x large bore IV cannulae
- Urgent bloods for: FBC, clotting, G&S (if not done previously) and cross-match
- Transfuse blood as soon as possible
- Continuous HR, BP and RR monitoring
- If the placenta is undelivered → attempt removal by controlled cord traction
- If the placenta is delivered → check for completeness (empty uterus and vagina of clots)
- Massage the uterus to stimulate uterine contractions
- Stepwise approach to pharmacological and surgical options:
o Step 1: IV/IM syntocinon or IM ergometrine or syntometrine (last 2 are contraindicated in asthma and HTN)
o Step 2: IM carboprost (not in asthmatics)
o Step 3: intrauterine balloon tamponade i.e. Bakri balloon.
o Step 4: other surgical measures (e.g. iliac artery ligation, uterine artery embolization IR, hysterectomy)
- Oxytocin (slow injection followed by continuous infusion)
- Ergometrine (intravenous or intramuscular) stimulates smooth muscle contraction (contraindicated in hypertension)
- Carboprost (intramuscular) is a prostaglandin analogue and stimulates uterine contraction (caution in asthma)
- Misoprostol (sublingual) is also a prostaglandin analogue and stimulates uterine contraction
- Tranexamic acid (intravenous) is an antifibrinolytic that reduces bleeding
- 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
What are the RFs for cord prolapse and presentation?
What is the optimal initial management of cord prolapse in a fully equipped hospital setting?
- When cord prolapse is diagnosed before full dilatation, assistance should be immediately called and preparations made for immediate birth in theatre.
- There are insufficient data to evaluate manual replacement of the prolapsed cord above the presenting part to allow continuation of labour. This practice is not recommended.
- To prevent vasospasm, there should be minimal handling of loops of cord lying outside the vagina.
- To prevent cord compression:
- it is recommended that the presenting part be elevated either manually or by filling the urinary bladder.
- can be further reduced by the mother adopting the knee–chest or left lateral (preferably with head down and pillow under the left hip) position.
- Tocolysis can be considered while preparing for caesarean section if there are persistent fetal heart rate abnormalities after attempts to prevent compression mechanically, particularly when birth is likely to be delayed.
- Although the measures described above are potentially useful during preparation for birth, they must not result in unnecessary delay.
