Assisted Vaginal Delivery

Assisted vaginal delivery

synopsis • • • • • •

Introduction Definition Prevalences How to lower OVD rates Types of AVD indications

introduction • Assisted vaginal delivery or operative vaginal delivery or instrumental vaginal delivery • Is the hallmark of obstetric practice • AVD offers the option of an operative procedure to accomplish delivery with the potential of safely and quickly removing the infant, mother and the obstetrian from a difficult or even hazardous situation. • When a spontaneous vag delivery does not occur within a reasonable period of time, a successful AVD avoids the need for C/S with its resultant uterine scar which has implication for future pregnancy.

definition • Operative vaginal delivery is an obstetric procedure in which active measures with specialized instruments is used to accomplish the delivery of the fetus through the vaginal route. • Absence of such assistance results in prolonged labour, undue delay in delivery with resultant fetal and or maternal jeopardy.

Prevalence of OVD • The prevalence varies between 1.5-15 per cent of deliveries – reason for the wide variance is due to the different method of labour management. • UPTH prevalence: 2001(3.1), 2002 (1.7)

How to lower OVD rates • Companionship during labour • Active management of the second stage of labour with syntocin • Upright posture during the second stage • A more liberal attitude to the duration of the second stage of labour when epidural analgesia is used in labour • Confirming fetal distress with fetal scalp sampling – in situations of fetal heart rate deceleration rather than a delivery.

Factors that determine success of operative vaginal delivery • Clear-cut indication for their use • The operator must have sufficient skill for the procedure. • The procedure must be appropriately timed.

Types of operative vag deli • Forceps delivery • Vacuum extraction • In developing countries include symphysiotomy and destructive operations – craniotomy, embryotomy, decapitation, cleidotomy.

Indications for OVD Major categories - To relieve dystocia - To prevent fetal jeopardy - To prevent maternal jeopardy

Maternal indications • Maternal distress • Maternal exhaustion • Medical conditions – cardiopulm dx, imminent Sickle cell crisis, eclampsia, intrapartum haemorrhage – abruptio placentae

• Undue prolongation of the 2nd stage of labour Duration of 2nd stage of labour – no specific time limit, provided no evidence of fetal distress and there is progress. However, consider intervention if duration of 2nd stage is longer than Primigravidae – 2 hrs; multip – 1 hr. (with regional anaesthesia primigravidae – 3hrs; multip – 2 hrs) - provided mother gives consent and fetal condition is satisfactory.

Fetal indications • Malposition – occipitoposterior or occipitotransverse • Delivery of premature infant – controversial • Delivery of the aftercoming head in assisted breech delivery • Fetal distress in second stage of labour.

Obstetric Forceps • These are specially designed instrument for delivery of the fetal head or correction of abnormal cephalopelvic relationship – asynclitism. • Instrument is made up of 2 halves, coupled by a lock – either English lock or the sliding lock. • Each half is comprised of the handle, shank and the blade which has a pelvic curve and cephalic curve

Types of obst forceps • Traction forceps – wrigley,Piper • Rotational forceps – kielland

Types of forceps delivery • Outlet forceps – the fetal head is at the perineum, visible at the introitus without separating the labia: i.e. the fetal skull has reached the pelvic floor and the sagittal suture is either in the anteroposterior direction or does not have to rotate for more than 450 to achieve this position. • Low forceps – in which the leading point of the skull (not caput) is at station +2 or more from the ischial spine, but does not reach the pelvic floor. • Mid forceps – the head is engaged, the station is not up to +2 below the ischial spine.

Prerequisites for forcep delivery • Cervix must be fully dilated. • Membrane must be ruptured. • Bladder and rectum must be empty. • Head must be engaged. • Position must be known • No cephalopelvic disproportion.

• Suitable presenting part – vertex, face (mentoanterior), aftercoming head of the breech. • Anaesthesia should be given. • Episiotomy is given. • The operator must have the necessary skill. • There must be informed consent for the procedure.

Complication of forcep use Maternal complications

Fetal complications

- Anaesthetic complications – esp if GA. - Genital tract injury – vaginal, cervical or uterine injury, lacerations or haematoma. - Bladder or urethral injury. - Acute postpartum urinary retention. - sepsis - Vesicovaginal fistula. - Rectovaginal fistula.

- Transient facial marks. - Facial palsies - Fractured facial bones or skull. - Intracranial haemorrhage. - Brachial plexus injury

Vacuum extractor • Works on the principle of a cup device attached by tubing to a pump to create enough negative pressure to allow traction on the cup which transfer this traction to the fetal head which as a result is pulled along the birth canal axis. Traction is applied during uterine contraction resulting in descent of the fetal head by a push-pull effect.

Types of ventouse cup • Metal cups (Malmstrom) • Silicone-rubber cup Bird’s modification of the metal cup - Anterior cup - Posterior cup

Prerequisite for ventouse • Cervical dilatation – 8cm • Cooperation of patient • Good contractions should be present. Basic rules for ventouse delivery - The head should descend with each pull. - The cup should be reapplied not more than twice. - The delivery should be completed within 15minutes of application of ventouse. - Following failure of ventouse, there is no place for trial of forcep.

• Indications for ventouse same as for forceps. • -

Contraindications Face presentation. GA less than 34 weeks Prior fetal scalp sampling.

Examination – - No head palpable per abdomen. - Position and the attitude of vertex must be known.

Delivery by ventouse • Position – lithotomy (commonest), dorsal, lateral or squatting. • Catheterisation (may or may not) • Anaesthesia – yes or no, perineal infiltration if there is need for episiotomy. • Set up and test ventouse. • Determine the cup type and size. • Insert the cup gently into the vagina – ensuring that no genital tissue is trapped within the cup.

• Cup placement over the point of flexion – anterior to the posterior fontanelle such that the edge of the cup is 3cm from the anterior fontanelle along the sagittal suture. • Proper cup placement results in flexion and synclitism. • The vacuum is created (8kg/cm2) • Traction is applied with uterine contraction and the parturient bearing down (pushing). • One hand rest on the cup in the vagina to determine descent with the traction and early cup detachment.

• Initial traction is downwards at 450 along the pelvis axis for the duration of uterine contraction. • When the head crowns, the direction of pull changes upwards through an arc of over 900 • At crowning – may give episiotomy.

complications Maternal - Less than with forceps - Genital trauma. - Cervical incompetence (rare).

Fetal - cephalhaematoma. - Subgaleal haematoma. - Intracranial haemorrhage – repeated application. - Transient neonatal neurological depression.

symphysiotomy • Borderline cephalopelvic disproportion to achieve vaginal delivery – live baby. • Women abhor caesarean delivery – care of subsequent delivery. • Main disadvantage – permanent instability of the pelvic girdle.

Destructive operations • Cephalopelvic disproportion with IUFD Types • Craniotomy • Decapitation • Cleidotomy • Embryotomy.