Principles Of Operative Deliveries And Management Of Previous Caesarean Section Flashcards
When should we deliver the baby?
Labour:
- Natural / Induced
- Aim: normal spontaneous vaginal delivery (safest in most cases)
- When complications / conditions arise (e.g. suspected fetal distress) —> ***Operative delivery
- Natural
- Spontaneous onset of labour + delivery - Before natural onset of labour
- Continuation of pregnancy may involve increased risk to mother / baby (e.g. Gestational HT, Postmaturity)
- Options
—> **Induce labour
——> Prostaglandin
——> Amniotomy (release prostaglandin from amniotic fluid)
——> Syntocinon
——> Amniotomy + Syntocinon
—> **Caesarean section
Operative deliveries
- Instrumental assisted vaginal deliveries
- **Ventouse (vacuum) extraction
- **Forceps - Abdominal delivery
- ***Caesarean section
—> Upper segment (Classical)
—> Lower segment (Common)
Episiotomy
- Surgical incision of **perineum made to increase diameter of **vulval outlet during childbirth
Indications:
1. **Instrumental delivery
2. **Shoulder dystocia
3. ***Fetal distress
4. Short / Rigid perineum
Methods:
- Mediolateral / Midline (may carry risk of injuring anus + rectum)
- LA / Epidural
Complications:
- Pain
- Infection
- Bleeding
- Gap
- Tear to anal sphincter, rectum
- Instrumental assisted vaginal deliveries
- Rate: 1.5-15%
Types:
1. Ventouse delivery
2. Forceps delivery
Indications (**記: 2nd stage):
1. Prolonged **2nd stage
2. Fetal distress in **2nd stage
3. Maternal disease (to shorten **2nd stage)
Prerequisites:
1. **Full dilatation of cervix
2. **Full engagement of the head
3. ***No features of gross cephalopelvic disproportion
4. Cooperation of the woman
5. Good uterine contractions
6. Empty bladder
Trial of instrumental delivery:
- Not certain if there is mild disproportion
- Apply forceps / ventouse in the theatre and observe progress when reasonable traction is exerted
- If advance is not maintained —> C/S can be carried out immediately
Ventouse delivery
Types:
1. Metal
- Anterior cup (for OA, suction port at surface of cup) / Posterior cup (for OP / Occipitotransverse, suction port at side of cup))
- ***Stronger traction force
- Soft (silicone-rubber) cups:
- **Less trauma to baby’s head but **higher failure rate
Placement of cup:
- Midline, Occiput, Flexion point
- A well-placed cup (in midline over occiput) —> result in a ***well-flexed head —> help in success of vaginal delivery
Basic rules:
1. Episiotomy (not a must)
2. Negative pressure of 0.8 kg/cm^2
3. Controlled 2-handed manner (1 hand on handle, 1 hand on head to detect descent + leakage of air + slip of cup)
4. Traction along the pelvic axis
5. Completed within 15 mins of application
6. Head should descend with each pull
7. Cup should be reapplied <=2 times
Reasons for failure:
1. Instrumental failure
2. Incorrect position of cup application
3. Cephalopelvic disproportion
Complications:
- Edema of head after cupping (**Chignon / Caput succadaneum)
—> important for cup to be well-applied
—> go away within 24-48 hours, important DDx: **Subgaleal haematoma (can kill)
Forceps delivery
- Can be used for OA / OP / Face (Mentoanterior) presentation
- Mentoposterior can only be delivered by C/S (∵ head already extended, cannot be extended further)
- Mentoanterior cannot be be delivered by vacuum (∵ vacuum cannot be applied onto baby’s face)
Types:
1. Outlet forceps (e.g. Wrigley)
- Used when head already very low down to perineum
- Low forceps (e.g. Simpson)
- Lowest point of head at >=2cm below ischial spine - Rotation from the OP to the OA (e.g. Kielland)
- Seldom performed since turning baby’s head at such a high position is dangerous for both mother + baby - Aftercoming head (e.g. Piper)
- For breech presentation
Indications:
1. **Fetal distress (when need to get baby out asap)
2. **Cord prolapse
3. **Face presentation (∵ vacuum cannot be applied by baby’s face)
4. **Preterm (<34 weeks, vacuum will increase chance of intracranial haemorrhage)
5. Marked active bleeding from a fetal blood sampling site (negative pressure by vacuum will increase further bleeding)
6. ***Aftercoming head of a breech (∵ vacuum no place to apply)
Ventouse vs Forceps delivery
Complications:
1. Trauma to genital tract including tear + haematoma
- Ventouse: Less, Episiotomy may not need
- Forceps: More, Episiotomy almost inevitable
- Pain, analgesia
- Ventouse: Less
- Forceps: More - Fetal injury
- Ventouse: **More dangerous
—> **Chignon / **Caput succadaneum (SC edema between skin and epicranial aponeurosis, **pitting)
—> **Cephalhaematoma (between periosteum and skull i.e. blood confined within periosteum —> cannot grow in size + not cross suture, self-limiting, **non-pitting)
—> ***Subgaleal / Subaponeurotic haemorrhage (between aponeurosis and periosteum, can cross suture, large potential space for bleeding)
—> Skull fracture
—> Intracranial injuries
- Forceps:
—> Forceps marks
—> **Face injuries (Facial nerve palsy)
—> **Skull fractures
Which is preferred?
- Operator’s choice
- Ventouse: Now preferred ∵ less trauma, more safe if rotation is required
Pathologies in Delivery
- Shoulder dystocia
- Breech presentation
- Vaginal twin delivery
- Shoulder dystocia
Definition:
- When the head is born but shoulders cannot be delivered by usual means
Epidemiology:
- 1 in 200-400 deliveries
Complications:
1. **Asphyxia
2. **Fractures
3. ***Brachial plexus injury (e.g. Erb’s palsy)
4. Death (rare)
Predisposing factors (Now remain unpredictable in majority):
1. Big baby
2. Small mother
3. DM
4. Past-term
5. Previous history
6. Prolonged 1st / 2nd stage
7. Instrumental delivery
Diagnosis:
1. ***Turtle sign (tendency of head to go back into birth canal / hesitancy of head to come out in full)
Management:
1. Call Paediatricians (for resuscitation) + Anaesthetist (prepare for surgery)
2. **McRobert’s manoeuvre (flex mother’s hip as much as possible)
3. **Episiotomy (generous)
4. Gentle head traction
5. **Rotate shoulders
- **Suprapubic pressure (push the back of anterior shoulder to collapse shoulder by force over mother’s abdomen)
- **Woods’ (corkscrew) manoeuvre (from AP to oblique position of shoulders, dislodge anterior shoulder from pubic symphysis)
6. **Deliver the posterior arm first
- by putting our hand into posterior side, compress rectum only (cannot do this anteriorly since blocked by pubic symphysis
7. ***Gaskin manoeuvre (all-4 position (四隻腳狗仔式))
- Breech presentation
**Vaginal breech delivery:
- Planned vaginal breech delivery is **NO LONGER an option after publication of term breech trial (Elective C/S safer than planned vaginal delivery)
—> ONLY apply to **Singleton + **Term + ***Breech (Pre-term breech / Secondary breech: can still try vaginal delivery)
Risks of Vaginal breech delivery:
Fetus:
1. **Hypoxia
2. Trauma
3. **Cord prolapse (compromise blood flow to baby)
4. **Intraventricular haemorrhage
5. **Entrapment of aftercoming head (pelvis not challenged prior to delivering the head (trunk is smaller than head))
Maternal:
1. **Genital tract trauma
2. **PPH
3. ***Emergency C/S
4. Anaesthesia
Causes (Felix Lai):
1. **By chance (majority)
2. Maternal: **Uterine abnormalities (e.g. Bicornuate uterus), **Placenta previa, **Fibroid
3. Fetal: **Multiple pregnancy, **Preterm infants, ***Fetal abnormalities
Solution:
1. **External cephalic version (ECV) (version: 旋轉) (外胎頭回轉術)
2. **Caesarean section
Assisted breech delivery (vaginal delivery):
1. Unit equipped for C/S
2. Experienced obstetrician
3. Fetal HR monitoring
4. **Episiotomy (generous)
5. **Hands-off (try to do as minimal intervention as possible)
6. **Keep baby’s back anterior (by gravity the neck is then flexed)
7. **Flexion of neck
8. Delivery of aftercoming head: **Mauriceau-Smellie-Veit manoeuvre (MSV) (one hand on maxilla and mouth to keep head flexed + suprapubic pressure) / **Forceps
External cephalic version (ECV) (Felix Lai)
- ***>=37 weeks
- Success rate = ***50%
Indications:
1. **Breech presentation at term
2. **Stabilizing induction for transverse, oblique and unstable lie
3. Rotate a non-cephalic presenting ***2nd twin into cephalic during 2nd stage of labour
Contraindications:
1. **Intrauterine growth restriction (IUGR)
2. **Placenta previa
3. **Multiple pregnancy
4. **Major uterine anomalies
5. **Previous uterine scar
6. **APH within 7 days
7. Oligohydramnios (NOT absolute)
8. Hypertension (NOT absolute)
Pre-procedural preparation:
1. **Fast >=6 hours prior to the procedures (prepare for emergency C/S if failed)
2. Type / Screen + Check Rh status (potentially sensitizing event)
- **Anti-D prophylaxis
3. Reactive NST is a prerequisite
4. Monitor Maternal BP + pulse
5. IV catheter before the procedure
6. ***Tocolytic is required for uterine relaxation
- 0.25 mg terbutaline is diluted in 10 mL NS and given IV over 2-3 min
- Terbutaline is used as 1st line rather than nifedipine since it is short-acting
- BP reading is repeated 5 mins after injection
7. Proceed to ECV if all the readings are normal
Procedures:
- In-patient procedure, admitted on the day of ECV
- **NO anesthesia is required
- Limited to **10 mins
- External pressure is applied by the doctors on the abdomen
- Patient may feel pain or discomfort during the procedure
- Procedure will be abandoned if patient cannot tolerate the discomfort / duration is >10 mins
Post-procedure assessment:
1. ***Post-ECV NST
2. FHR is checked with USG scan after ECV
- In case of persistent fetal bradycardia —> can be immediately transferred for emergency C/S
3. Successful ECV —> Allowed to go home on the same day with 1-week FU in antenatal clinic and subsequent management is same as normal cephalic presentation
4. Failed ECV —> Appointment for elective C/S at 38-39 weeks will be given before discharge if no complications after 2-4 hours of observation with NST performed
- USG before elective C/S to check again and in case turned into cephalic presentation can cancel elective operation
Complications:
1. **Transient fetal bradycardia (most common)
- 3-10%
- lasting for seconds to few minutes
- No long-term sequelae will 0.4% requiring investigation for persistent episodes
2. Fetal distress requiring immediate Caesarean section (0.5%)
3. **Reversion (3%)
4. **Uterine rupture
5. **Placental abruption
6. **Cord accident
7. **Rupture of membrane
- Vaginal twin delivery
Major risks are to 2nd twin:
1. **Premature separation of placenta
2. Malpresentation: **Transverse lie / **Breech, **cord prolapse
3. Excessive manipulation needed
Management:
1. Unit equipped for C/S
2. Experienced obstetrician, anaesthetist, paediatrician
3. **Epidural analgesia (∵ increased need for manipulation)
4. **Monitoring of fetal heart of BOTH twins
5. 1st twin must be ***Cephalic
After delivery of 1st twin:
1. Clamp cord tightly
2. **Check lie of 2nd twin (must be **longitudinal, otherwise do external / internal version)
3. **External / Internal version if transverse
4. **Oxytocin infusion if inadequate uterine contractions
5. **Amniotomy (don’t break too early otherwise cord prolapse ∵ baby high in position)
6. **C/S if
- Persistent transverse lie
- Fetal distress with high presentation
Delivery of twin (Felix Lai)
Optimal time to deliver depends on chorionicity and amnionicity:
1. DCDA = **38 weeks to 38+6 weeks
2. MCDA = **36 weeks to 36+6 weeks
- Reasonable trade-off between the morbidity of preterm birth and risk of unanticipated fetal demise and higher risk of stillbirth beyond this gestation age
- Some society guidelines suggests delaying delivery up to 37 + 6 weeks
3. MCMA = **34 weeks (By Caesarean section)
4. Triplets = **34 weeks (By Caesarean section)
Malpresentation are common in twin pregnancy:
- 75% of Twin 1 presents by **Vertex
- Lie of the 2nd baby is **NOT important
**Caesarean section is indicated when the 1st twin is **NON-cephalic
Delivery of 2nd twin after 1st twin by vaginal:
Risk of delivery of 2nd twin:
- Presentation of 2nd twin may remain high or altered, uterine contractions are diminished (uterine inertia), cervix may begin to close
- Major risks: **Cord prolapse, **Diminished placental function, ***Abruptio placentae —> hypoxic injury / haemorrhage from 2nd twin
After vaginal delivery of 1st twin:
- **Vaginal examination to assess station of 2nd twin
- **USG to assess the presentation of 2nd twin
- Options if the presentation of 2nd twin is not cephalic:
1. **ECV with cephalic delivery
2. **Internal podalic version with vaginal breech delivery
3. Breech extraction
- **Oxytocin augmentation should be considered when uterine inertia occurs
- Membranes should not be ruptured (Amniotomy) until the fetal head is well-engaged otherwise there will be risk of cord prolapse if baby is still high
- Convert to **Caesarean section if fetal remains high in presentation after 30 mins or when there is evidence of fetal distress
Caesarean section
- Elective C/S is usually performed at ***38-39 weeks (reduce chance of wet lung (ARDS))
- Sometimes earlier after balancing risks to mother / fetus against risk of prematurity
- C/S on maternal request: Debatable
Indications of C/S:
1. Elective (operation before onset of labour) (**Mother factor + **Baby factor + **Placenta factor)
- **Previous C/S or **Scar
- **Severe pre-eclampsia
- **Breech
- **Multiple pregnancy
- ***Placenta previa (placenta completely or partially covers the opening of the uterus (cervix))
- Emergency
- **Fetal distress
- **Cephalopelvic disproportion
(- Failure to progress during labour
- Failed induction of labour
- Failed instrumental delivery
- Chorioamnionitis
- Non-reassuring fetal status
—> Cord prolapse
—> Prolonged bradycardia) (Felix Lai)
Types:
1. Upper segment (Classical, rare, more complications)
- **Lower segment poorly formed (preterm, delivery before 28 weeks)
- **Lower segment with large vessels (placenta previa) / fibroid / severe adhesions
- ***Transverse lie with back inferior (∵ cannot grab hold of baby)
- Perimortem C/S (aim to save mother, delivery asap)
2. Lower segment (Common)
Types of abdominal incision:
1. Midline vertical
2. Maylard
3. Joel-Cohen
4. Pfannenstiel
Types of uterine incision:
1. Lower transverse (most common)
2. Lower vertical
3. Lower transverse + J-shape extension (Combined lower + upper segment)
4. Lower transverse + Inverted T-shape extension (Combined lower + upper segment)
5. Vertical (i.e. Upper segment)
—> Upper segment: chance of uterine rupture in next pregnancy much higher —> do NOT try vaginal delivery next pregnancy
Process:
1. Premedication with antacids (prevent aspiration pneumonia)
2. Left lateral position (avoid ***aortocaval compression (ACC), maintain blood supply to uterus)
3. Catheterise bladder (avoid bladder injury)
4. Skin incision: Lower transverse / Midline
5. Uterine incision: Lower transverse / Lower vertical (try to avoid this since cut may go up —> become upper segment incision)
6. Delivery of fetus
7. Delivery of placenta
8. Closure of uterus, rectus sheath, skin
Complications:
Short-term:
1. **Haemorrhage (Risk of hysterectomy (SpC OG))
2. **Injuries to fetus, bowel, bladder, ureters
3. **Infections
4. **Anaesthesia
5. **Mendelson’s syndrome (Aspiration of stomach contents (mainly gastric acid) during anaesthesia —> Aspiration pneumonitis)
6. **Thromboembolism
7. ***Wound problems
Long-term:
1. **Scar rupture
2. **Placenta accreta (植入性胎盤)
(All / part of placenta attaches abnormally to myometrium, 3 grades according to depth of invasion:
—> Accreta: attached to myometrium, rather than being restricted within the decidua basalis
—> Increta: chorionic villi invaded into the myometrium
—> Percreta: chorionic villi invaded through the perimetrium (uterine serosa) to bladder / rectum)
Classical C/S (Felix Lai)
- 0.4%
- Vertical incision that extends into upper uterine segment or fundus
- Allows larger space for delivery
- Rarely performed at term or near term since it is associated with a much higher frequency of uterine rupture or dehiscence
Indications:
1. **Preterm delivery
- Lower segment has not been formed / poorly developed
2. **Lower uterine segment pathology
- Anterior placenta previa (not necessarily true now)
- Placenta accreta
- Large fibroid
3. Back-down transverse lie
- More than normal intrauterine manipulation is anticipated
4. Postmortem delivery
- Main aim: save the mother
