Instrumental and Operative Delivery Flashcards
How do forceps or ventouse aid delivery?
Allow use of traction if delivery needs to be expedited in the 2nd stage
rotation, and power
Aim = prevent foetal and maternal morbidity associated with prolonged 2nd stage or expedite where the foetus is compromised
What is a ventouse?
plastic, rubber or metal cap connected to a handle - the cap is fixed near the foetal occiput by suction
Traction during maternal pushing will deliver the OS position head - it often also allows the shape of the pelvis to simultaneously rotate a malpositioned head to the OA position
How do obstetric forceps work?
come in pairs that fit together for use - each has a ‘blade’, shank, lock and handle.
When assembled, the blade fits around the foetal head and the handles fit together
the lock prevents them from slipping apart
How do non-rotational forceps work?
grip the head in whatever position it is in and allows traction - only suitable for OA position.
They have a cephalic curve for the head and a pelvic curve which follows the sacral curve
What do rotational forceps do?
Have no pelvic curve and enable a malpositioned head to be rotated by the operator and an OA position before traction is applied
What are the complications of ventouse and forceps?
The key risks to remember to the baby are:
Cephalohaematoma with ventouse
Facial nerve palsy with forceps / bruising with forceps
What method is more likely to fail - ventouse or forceps?
Ventouse - he cup can be placed inaccurately
What are the maternal complications of instrumental delivery?
Postpartum haemorrhage Episiotomy Perineal tears Injury to the anal sphincter Incontinence of the bladder or bowel Nerve injury (obturator or femoral nerve)
What are the foetal complications of instrumental delivery?
Slightly worse with ventouse - chignon (swelling on scalp) - drawn with suction of cup
scalp lacerations, Cephalhaematomae and neonatal jaundice all more common with ventouse
facial bruising, facial nerve damage and skull fractures can occasionally occur with injudicious use of forceps and prolonged traction by either instrument is dangerous
What are the indications for instrumental vaginal delivery?
Failure to progress
Fetal distress
Maternal exhaustion
Control of the head in various fetal positions
What is a low-cavity delivery?
Head is well below the ischial spines - bony prominences palpable vaginally on the lateral wall of the mid-pelvis - usually OA position
How can instruments be used to aid low-cavity delivery?
Both appropriate - ventouse better if maternal effort is poor - pudendal block with perineal infiltration is usually sufficient analgesia
What is mid-cavity delivery?
Head is engaged, but at or just below the level of the ischial spines - epidural or spinal anaesthesia is usual
If there is any doubt that delivery will be successful, it is attempted in the operating theatre, with full preparations for a C-section
In what abnormal positions can instruments be used?
OA - forceps or ventouse
OT - usually the result of insufficient descent of the head to make it rotate - descent is achieved with ventouse - rotation in situ followed by descent can also be achieved by manual rotation or Kiellan’s rotational forceps
OP - often accompanied by extension of the foetal head, making the presenting diameter too large for the pelvis - dragging out a baby in this position may fail or cause severe perineal damage. rotation of 180 degrees can be achieved manually or with the ventouse/Kielland’s forceps
What are the prerequisites for instrumental vaginal delivery?
Head must not be palpable abdominally
On vaginal examination, the head must be at or below the level of the ischial spines
The cervix must be fully dilated
position of the head must be known
There must be adequate analgesia
The bladder should be empty
What % of births in the developed world are by C-section?
25%
What is the usual operation for C-section?
LSCS
abdominal wall is opened with a suprapubic transverse incision - the lower segment of the uterus is also incised transversely to deliver the baby
When is an emergency C-section performed?
labour - may also occur with acute antepartum problems e.g. placental abruption
Prolonged first stage
Foetal distress
What is the diagnosis of a prolonged 1st stage?
when full dilation is not imminent by 12-16 hours or earlier if labour was initially rapid
Occasionally, full dilation achieved, but not all the criteria for instrumental delivery are met. Most commonly, it is due to abnormalities of the ‘powers’ - e.g. insufficient uterine action - the passenger or passage may also contribute
What is an elective C-section? When is it needed?
Performed to avoid labour - normally at 39 weeks as this reduces the risk of transient tachypnoea of the newborn from 6% (38 weeks) to 4%. If earlier, administration of steroids should be considered
When delivery is needed before 34 weeks, usual to perform C-section rather than induce labour (pre-eclampsia and severe IUGR)
What are the absolute indications to elective C-section?
placenta praevia severe antenatal foetal compromise uncorrectable abnormal lie previous vertical c-section gross pelvic deformity
What are the relative indications of elective C-section?
breech presentation severe IUGR twin pregnancy certain medical disorders Previous C-section Older nulliparous patients
What are the maternal complications of C-section?
haemorrhage
need for blood transfusion
infection of the uterus or wound
damage to surrounding structures e.g. bladder or bowel damage
post-operative pain and immobility
VTE
What prophylaxis Is given for C-sections?
H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
Prophylactic antibiotics during the procedure to reduce the risk of infection
Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin
What are the foetal complications of C-section?
elective procedure increases the risk of foetal respiratory morbidity at any given gestation - in uncomplicated pregnancy, it is not recommended before 39 weeks
Fetal lacerations
Bonding and breastfeeding - affected by emergency procedures
What is the effect of c-section on subsequent pregnancies?
Increased risk of repeat caesarean
Increased risk of uterine rupture
Increased risk of placenta praevia
Increased risk of stillbirth
