Assisted Vaginal Delivery

Assisted vaginal delivery refers to delivery of a baby vaginally using an instrument for assistance.

The primary functions are:

• To assist with traction of the fetal head and/or
• To assist with rotation of the fetal head to a more desirable position.

The incidence rate varies

Czech Republic - 1.5% of deliveries

15% in Australia and Canada.

In US Vacuum delivery is more common than obstetric forceps delivery with ratio of 4:1.

In the past forceps delivery was more common than vacuum delivery.

Forceps delivery skill is being lost due to:

• Fear of litigation
• Vacuum delivery appears safer
• Use of c/s as alternative option
• Decreased number of residency programs that actively train residents in the use of forceps

The success and safety of assisted vaginal delivery procedures are dependent on:

• On operator skill
• Abiding with prerequisites
• Avoiding the contraindications
• Timely discontinuing when necessary and recourse to c/s

Types of assisted vaginal deliveries

• Vacuum extraction
• Forceps delivery
• Symphysiotomy
• Manual rotation

Vacuum extraction (VE), also known as ventouse, is a method to assist delivery of a baby’s head using a vacuum device during second stage of labor.

The term "Ventouse" comes from the French word for "suction cup".

Tage Malmstrom developed the ventouse, or Malmstrom extractor in the 1950s.

It was originally made with a metal cap, new materials such as plastics and siliconised rubber have improved the design and make it more baby friendly

Components of Malmstrom vacuum extractor:

• Metal cup,
• Traction chain,
• A separate vacuum pipe and
• A pump.

The cups comes in 4, 5, 6cm sizes.

Indications

• Delay in second stage
• Fetal distress in second stage
• Maternal conditions requiring short second stage

Contraindications

• Preterm baby
• Breech presentation

Pre-requisites

• Term pregnancy
• Full cervical dilatation
• Engaged fetal head preferably 1/5th or less.
• Pelvis adequate Membrane ruptured
• Empty bladder
• Good uterine contraction
• Co-operation of the patient
• Episiotomy should be given if necessary

Technique of application

• Test the equipment
• Patient should be in lithotomy position
• Clean the perineum
• Empty the bladder
• Perform vaginal examination to confirm station and position
• Part the labia and gently insert the vacuum extractor cup into the vagina and apply to the flexion point (2-3cm anterior to the posterior fontanelle)
• Check round the cup to ensure that vagina tissue is not trapped
• Then create vacuum up to 0.8kg/cm2 (upper part of green color)
• Begin traction with next contraction along the pelvic axis
• Release the vacuum at delivery of baby's head and remove the cup

Failed vacuum extraction

• If fetal head does not advance with each pull
• No descent to pelvic floor after maximum of three contractions/pulls
• Cup slips off the head twice at proper direction of pull with recommended maximum negative pressure

Complications

• The risk of complications to mother and baby is small if the rules that guide its use are adhered to and with good technique
• To Baby - chignon/cephalhaematoma (subperiosteal bleed), scalp abrasion, neonatal jaundice. Intracranial injury is rare.
• Mother-vaginal, cervical laceration, perineal laceration, haemorrhage

Introduction

The obstetric forceps is an instrument designed to assist with delivery of the baby's head.

The invention of the precursor to modern forceps is credited to Peter Chamberlin in the 1600s which was kept secret by the Chamberlin family in London.

Classification of obstetric forceps-

• High
• Midcavity
• Low
• Outlet forceps

High forceps delivery is dangerous and contraindicated.

The most common type is outlet forceps delivery

Components of obstetric forceps

• All forceps consist of two crossing branches that articulate.
• Each branch comprises of four parts: the blade, shank, lock, and handle.
• Each blade has two curves: the cephalic curve that conforms to the shape of the fetal head and the pelvic curve that conforms to the shape of maternal pelvic axis
• Some blades are fenestrated, and some are solid

The tip of each blade is called the toe.

The front of the forceps is the concave side of the pelvic curve.

The blades are referred to as left and right according to the side of the mother's pelvis on which they lie after application.

Indications

• Prolonged second stage of labor due to maternal exhaustion
• Expedite delivery in second stage of labor in fetal compromise such as fetal distress, cord prolapse in 2nd stage of labor
• Shortening of 2nd stage for maternal benefit such as in medical conditions like eclampsia, maternal anemia, obstructive airway diseases, etc.
• After coming head of the breech
• Preterm breech

Contraindications

• Cervix not fully dilated
• Head not engaged
• Inadequate pelvis

Pre-requisites for forceps delivery

• There should be indication
• Adequate pelvis
• Membrane ruptured
• Cervix fully dilated
• Position of fetal head is determined
• Station of fetal is determined
• Head is engaged
• Bladder is empty
• Operator should be skilled in forceps delivery
• Episiotomy is required
• Consent obtained

Outlet forceps delivery

Forceps applications:

• For application of left blade, two or more fingers of right hand are introduced inside the left posterior portion of vulva and into vagina beside the fetal head.
• The handle of left branch is then grasped between the thumb and two fingers of left hand and introduce under the guidance of the right hand.
• For application of right blade, two or more fingers of the left hand are introduced into the right posterior position of the vagina to serve as guide for right blade.

Complications

Maternal: Perineal, vaginal, cervical and uterine injuries from undue traction and rotator forces.

Injury to the baby's head