In addition to these evidence-based recommendations, the guideline development group also identifies points of best clinical practice in the original guideline document.
Levels of evidence (Ia-IV) and grading of recommendations (A-C) are defined at the end of the "Major Recommendations" field.
Preparation for Operative Vaginal Delivery
Can Operative Vaginal Delivery be Avoided?
A - All women should be encouraged to have continuous support during labour. Use of a partogram, use of upright or lateral positions, and avoiding epidural analgesia will reduce the need for operative vaginal delivery. Oxytocin in primiparous women with epidurals will decrease the need for operative vaginal delivery. Delayed pushing in primiparous women with an epidural will reduce the risk of rotational and mid-cavity deliveries.
In primiparous women with epidural anaesthesia, starting oxytocin in the second stage of labour can reduce the need for non-rotational forceps delivery. Extreme caution should be taken before using oxytocin for the second stage in multiparous women. Each woman should be assessed individually for the management of the second stage. (Evidence level Ib)
How Should Operative Vaginal Delivery Be Defined?
C - A standard classification of operative vaginal delivery should be used.
To enable benchmarking, audit, and comparison between studies, a standard definition of the types of operative delivery should be used. The American College of Obstetricians and Gynecologists criteria are adapted in the table below titled "Classification for Operative Vaginal Delivery" and define the delivery by the station and position. (Evidence level IV)
Classification for Operative Vaginal Delivery (Adapted from ACOG 2000)
| Term |
Definition |
| Outlet |
- Fetal scalp visible without separating the labia
- Fetal skull has reached the pelvic floor
- Sagittal suture is in the antero-posterior diameter or right or left occiput anterior or posterior position (rotation does not exceed 45 degrees)
- Fetal head is at or on the perineum
|
| Low |
- Leading point of the skull (not caput) is at station plus 2 cm or more and not on the pelvic floor
- Two subdivisions:
- rotation of 45 degrees or less
- rotation more than 45 degrees
|
| Mid |
- Fetal head is 1/5 palpable per abdomen
- Leading point of the skull is above station plus 2 cm but not above the ischial spines
- Two subdivisions
- rotation of 45 degrees or less
- rotation more than 45 degrees
|
| High |
Not included in classification |
When Should Operative Vaginal Delivery Be Offered?
C - Operators should be aware that no indication is absolute and should be able to distinguish "standard" from "special" indications.
Operative intervention is used to shorten the second stage of labour. It may be indicated for conditions of the fetus or of the mother (see table below titled "Indications for Operative Vaginal Delivery"). (Evidence level III)
Indications for Operative Vaginal Delivery (no indication is absolute and each case should be considered individually)
| Type |
Indication |
| Fetal |
Presumed fetal compromise |
| Maternal |
Medical indications to avoid Valsalva (e.g., cardiac disease Class III or IVa hypertensive crises, cerebral vascular disease, particularly uncorrected cerebral vascular malformations, myasthenia gravis, spinal cord injury) |
| Inadequate progress |
Nulliparous women: lack of continuing progress for three hours (total of active and passive second stage labour) with regional anaesthesia, or two hours without regional anaesthesia
Multiparous women: lack of continuing progress for two hours (total of active and passive second stage labour) with regional anaesthesia, or one hour without regional anaesthesia
Maternal fatigue/exhaustion |
a New York Heart Association classification
Fetal bleeding disorders (e.g. alloimmune thrombocytopenia) or a predisposition to fracture (e.g. osteogenesis imperfecta) are relative contraindications to operative vaginal delivery. However, there may be considerable fetal risk if the head has to be delivered abdominally from deep in the pelvis. The risk of vertical transmission of hepatitis C virus appears to be related to the level of viraemia in the pregnant mother and not to the route of delivery. However, it is sensible to avoid difficult operative delivery where there is an increased chance of fetal abrasion or scalp trauma, as it is to avoid fetal scalp clips or blood sampling during labour. (Evidence level IV)
The vacuum extractor is contraindicated with a face presentation. It has been suggested that it should not be used at gestations of less than 36 weeks because of the risk of cephalohaematoma and intracranial haemorrhage. (Evidence level IV)
At present, the Royal College of Obstetricians and Gynaecologists (RCOG) recommends avoiding the use of vacuum below 34 weeks because of the susceptibility of the preterm infant to cephalohaematoma, intracranial haemorrhage, and neonatal jaundice. (Evidence level IV)
Forceps and vacuum extractor deliveries before full dilatation of the cervix are contraindicated. There are a few exceptions which include a prolapsed cord at 9 cm in a multiparous woman or a second twin. Forceps are indicated for the aftercoming head of the breech and in situations where maternal effort is impossible or contraindicated. (Evidence level III)
What are the Essential Conditions for Safe Operative Vaginal Delivery?
C - Safe operative vaginal delivery requires a careful assessment of the clinical situation, clear communication with the mother and healthcare personnel, and expertise in the chosen procedure.
Like any operative intervention, adequate preparation and planning is important. Be cautious in the urgent situation and at handover periods when time pressures can limit the information given (see table below).
Prerequisites for Operative Vaginal Delivery*
| Preparation |
Essential |
| Full abdominal and vaginal examination |
- Head is < 1/5 palpable per abdomen
- Vertex presentation
- Cervix is fully dilated and the membranes ruptured
- Exact position of the head can be determined so proper placement of the instrument can be achieved
- Pelvis is deemed adequate
|
| Mother |
- Informed consent must be obtained and clear explanation given
- Appropriate analgesia is in place, for mid-cavity rotational deliveries this will usually be a regional block
- A pudendal block may be appropriate, particularly in the context of urgent delivery
- Maternal bladder has been emptied recently
- Indwelling catheter should be removed or balloon deflated
- Aseptic techniques
|
| Staff |
- Operator must have the knowledge, experience, and skills necessary to use the instruments
- Adequate facilities and back-up personnel are available
- Back-up plan in place in case of failure to deliver
- Anticipation of complications that may arise (e.g., shoulder dystocia, postpartum haemorrhage)
- Personnel present who are trained in neonatal resuscitation
|
*Adapted from SOGC Clinical practice guideline No 148, August 2004 Guidelines for operative vaginal birth. J Obstet Gynaecol Can 2004;26:747-53; Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Instrumental Vaginal Delivery. College Statement No.C-Obs 16.Melbourne:RANZCOG;2004. [www.ranzcog.edu.au/publications/statements/C-obs16.pdf]; Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Guidelines for Use of Rotational Forceps. College Statement No. C-Obs 13. Melbourne:RANZCOG; 2004 ["www.ranzcog.edu.au/publications/statements/C-obs13.pdf].
Performing Operative Vaginal Delivery
Who Should Perform Operative Vaginal Delivery?
C - The operator must have the knowledge, experience, and skills necessary to use the instruments and manage complications that may arise.
Where Should Operative Vaginal Delivery Take Place?
C - Operative vaginal births that have a higher rate of failure should be considered a trial and conducted in a place where immediate recourse to caesarean section can be undertaken.
What Instruments Should be Used for Operative Vaginal Delivery?
A - The operator should choose the instrument most appropriate to the clinical circumstances and their level of skill. Forceps and vacuum extraction are associated with different benefits and risks.
When Should Operative Vaginal Delivery be Abandoned?
Operative vaginal delivery should not be attempted unless the criteria for safe delivery have been met (see table above entitled "Prerequisites for Operative Vaginal Delivery").
B - Operative vaginal delivery should be abandoned where there is no evidence of progressive descent with each pull or where delivery is not imminent following three pulls of a correctly applied instrument by an experienced operator.
Is There a Place for Sequential Use of Instruments?
B - The use of sequential instruments is associated with an increased risk of trauma to the infant. However, the operator must balance the risks of a caesarean section following failed vacuum extraction with the risks of forceps delivery following failed vacuum extraction.
The sequential use of instruments should not be attempted by an inexperienced operator without direct supervision and should be avoided wherever possible.
Should Prophylactic Antibiotics be Given?
A - There is insufficient data to make recommendations regarding prophylactic antibiotics in operative vaginal delivery.
Aftercare Following Operative Vaginal Delivery
Should Thromboprophylaxis be Given?
C - Women should be reassessed after an operative delivery for risk factors for venous thromboembolism.
What Precautions Should be Taken for Care of the Bladder after Delivery?
C - The timing and volume of the first void urine should be monitored.
A - Women should be offered physiotherapy-directed strategies to prevent urinary incontinence.
Urine retention with bladder overdistension should be avoided, particularly in women who have had spinal or dense epidural blocks. (Evidence level III)
How Can We Reduce Psychological Morbidity for the Mother?
A - There is no evidence to support the use of midwife-led debriefing in reducing maternal depression following operative vaginal delivery.
How Should We Advise Women for Future Deliveries?
B - Women should be encouraged to aim for a spontaneous vaginal delivery in a subsequent pregnancy, as there is a high probability of success.
This discussion should take place at the earliest opportunity, as there is evidence to suggest that women decide on future mode of delivery soon after delivery. The future plan of care should be reviewed carefully with women who have experienced a third- or fourth-degree tear, particularly if they are symptomatic, as they may be at increased risk of further anorectal damage with a subsequent delivery. (Evidence level IIa)
Definitions:
Grading of Recommendations
Grade A - Requires at least one randomised controlled trial as part of a body of literature of overall good quality and consistency addressing the specific recommendation (evidence levels Ia, Ib)
Grade B - Requires the availability of well-conducted clinical studies but no randomised clinical trials on the topic of recommendations (evidence levels IIa, IIb, III)
Grade C - Requires evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates an absence of directly applicable clinical studies of good quality (evidence level IV)
Levels of Evidence
Ia: Evidence obtained from meta-analysis of randomised controlled trials
Ib: Evidence obtained from at least one randomised controlled trial
IIa: Evidence obtained from at least one well-designed controlled study without randomisation
IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study
III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies
IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities
