Instrumental vaginal birth

Quality statement 3

When intervention is indicated in a vaginal birth, the choice of intervention is based on the clinical situation, the benefits and risks of each option and discussion with the woman.

Purpose

To ensure that decisions about an instrumental vaginal birth consider the individual clinical circumstances, and the benefits and risks of each option, including the risk of a third or fourth degree perineal tear, and the potential benefit of episiotomy.

For women

If your doctor or midwife is concerned about your health or the health of your baby during labour, they may suggest active assistance using either forceps or vacuum to help you have a vaginal birth.

Most instrumental births occur without complications, but there is a chance of serious risk to you or your baby. These risks need to be balanced against the risk of ‘waiting’ or using a different intervention.

Both forceps and vacuum increase the risk of a third or fourth degree perineal tear, especially for women having their first vaginal birth. The risk is higher with forceps than with vacuum. However, each woman’s situation is different and a number of factors will be considered before an instrument is recommended for you. If forceps or vacuum are used, you may be offered an episiotomy to lower the chance of having a third or fourth degree perineal tear.

In very few situations, an alternative to using forceps or vacuum may be an unplanned caesarean section where you have an operation and the baby is born via a cut through the abdomen and uterus.

A member of your healthcare team will discuss your situation with you, including the possible benefits and risks to you and your baby, for each available option. You may wish to discuss these options during pregnancy, in case you are offered forceps or vacuum during labour.

This care will be only be provided with consent from you, or your legal representative or guardian.

For clinicians

When an instrumental vaginal birth is indicated and more than one instrument may be appropriate, the choice of intervention should take into account evidence of the relative benefits and risks of the various instruments, the clinician’s skill and the woman’s preference.

Instrumental vaginal birth may be indicated when there is:

  • Fetal compromise
  • A need to reduce the effects of the second stage of labour because of a medical condition
  • Slow progress in the second stage of labour, associated with risks to the woman or fetus.

Current guidance from the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and the Royal College of Obstetricians and Gynaecologists (RCOG) include recommendations regarding the conditions for a safe instrumental vaginal birth (see Box 3).


Box 3: Conditions required for safe instrumental vaginal birth

Safe instrumental vaginal birth requires a careful assessment of the clinical situation, clear communication with the woman, and should be performed by, or in the presence of, an operator with expertise in the chosen procedure and the management of any complications which may arise.

For further detail see Royal Australian and New Zealand College of Obstetricians and Gynaecologists. 6. Instrumental vaginal birth. Melbourne: RANZCOG; 2016.


Clinicians should discuss with the woman the evidence regarding the risk profiles for both forceps and vacuum-assisted birth, as well as the benefits and risks of an unplanned caesarean section.

Forceps use is associated with increased risk of a third or fourth degree perineal tear and other vaginal trauma compared with vacuum-assisted birth. Both carry a small risk of any neonatal injury, but the nature of injuries differs between instruments (see Table 2).


Table 2: Summary of risk associated with forceps and vacuum-assisted birth

Forceps compared with vacuum

Risk estimate

Absolute rates
(% of operative births)

More likely to cause

 

 

  • Third or fourth degree tears

RR; 1.89 (95% CI 1.51–2.37)

14% vs 7%

  • Any type of vaginal trauma
RR; 2.48 (95% CI 1.59–3.87)

26% vs 12%

  • Facial injury
RR; 5.10 (95% 1.12–23.25)

1.7% vs 0.2%

More likely to

 

 

  • Achieve a vaginal birth

RR; 0.65 (95% CI 0.45–0.94)

91% vs 86% successful vaginal birth

No significant difference between instruments

  • Any neonatal injury
  • Low Apgar score (<7) at 5 minutes
  • Low pH (<7.2) in umbilical artery at birth

 

 


CI = confidence interval; RR = relative risk


During a first vaginal birth where instruments are used, medio-lateral episiotomy (with an incision angle of 60°) reduces the risk of a third or fourth degree tear. Tools to help ensure the correct angle of incision include special episiotomy scissors, such as Episcissors‑60, which may assist midwives and obstetricians achieve a post-suturing angle of 40–60°. The protective effect of episiotomy is highest when forceps are used, especially with a first time vaginal birth.

Additional planning is recommended in case a vaginal birth is not achieved with the first approach, and the risks of subsequent options should be considered (for example, sequential use of instruments or caesarean section at full dilatation).

Early discussion during pregnancy about these possible interventions may help prepare the woman should she face this situation. The discussion and her consent should be documented in her healthcare record.

For health service organisations

Ensure that policies, procedures and protocols include the management of instrumental vaginal birth, discussion with the woman about the possible benefits and risks associated with the available options and informed consent.

Ensure that conditions for a safe instrumental vaginal birth, as described in relevant clinical guidelines, are met within the facility, particularly with regard to availability of senior staff, facilities and back-up plans in case an instrumental birth is not successful.

Ensure that clinicians are appropriately trained and experienced to provide safe, high-quality care during an instrumental vaginal birth in accordance with professional standards, and are working within their scope of clinical practice. Ensure junior staff who do not have the requisite skills are supported by an experienced clinician.

Ensure that systems are in place to monitor variation in practice against expected health outcomes, as per Action 1.28 in the NSQHS Standards (2nd ed.), including rates of instrumental births and perineal trauma.

Provide timely feedback to clinicians on variation in practice and support them to review their clinical practice.

Record risks and the planned mitigation strategies in the risk management system.

For women

If your doctor or midwife is concerned about your health or the health of your baby during labour, they may suggest active assistance using either forceps or vacuum to help you have a vaginal birth.

Most instrumental births occur without complications, but there is a chance of serious risk to you or your baby. These risks need to be balanced against the risk of ‘waiting’ or using a different intervention.

Both forceps and vacuum increase the risk of a third or fourth degree perineal tear, especially for women having their first vaginal birth. The risk is higher with forceps than with vacuum. However, each woman’s situation is different and a number of factors will be considered before an instrument is recommended for you. If forceps or vacuum are used, you may be offered an episiotomy to lower the chance of having a third or fourth degree perineal tear.

In very few situations, an alternative to using forceps or vacuum may be an unplanned caesarean section where you have an operation and the baby is born via a cut through the abdomen and uterus.

A member of your healthcare team will discuss your situation with you, including the possible benefits and risks to you and your baby, for each available option. You may wish to discuss these options during pregnancy, in case you are offered forceps or vacuum during labour.

This care will be only be provided with consent from you, or your legal representative or guardian.

For clinicians

When an instrumental vaginal birth is indicated and more than one instrument may be appropriate, the choice of intervention should take into account evidence of the relative benefits and risks of the various instruments, the clinician’s skill and the woman’s preference.

Instrumental vaginal birth may be indicated when there is:

  • Fetal compromise
  • A need to reduce the effects of the second stage of labour because of a medical condition
  • Slow progress in the second stage of labour, associated with risks to the woman or fetus.

Current guidance from the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and the Royal College of Obstetricians and Gynaecologists (RCOG) include recommendations regarding the conditions for a safe instrumental vaginal birth (see Box 3).


Box 3: Conditions required for safe instrumental vaginal birth

Safe instrumental vaginal birth requires a careful assessment of the clinical situation, clear communication with the woman, and should be performed by, or in the presence of, an operator with expertise in the chosen procedure and the management of any complications which may arise.

For further detail see Royal Australian and New Zealand College of Obstetricians and Gynaecologists. 6. Instrumental vaginal birth. Melbourne: RANZCOG; 2016.


Clinicians should discuss with the woman the evidence regarding the risk profiles for both forceps and vacuum-assisted birth, as well as the benefits and risks of an unplanned caesarean section.

Forceps use is associated with increased risk of a third or fourth degree perineal tear and other vaginal trauma compared with vacuum-assisted birth. Both carry a small risk of any neonatal injury, but the nature of injuries differs between instruments (see Table 2).


Table 2: Summary of risk associated with forceps and vacuum-assisted birth

Forceps compared with vacuum

Risk estimate

Absolute rates
(% of operative births)

More likely to cause

 

 

  • Third or fourth degree tears

RR; 1.89 (95% CI 1.51–2.37)

14% vs 7%

  • Any type of vaginal trauma
RR; 2.48 (95% CI 1.59–3.87)

26% vs 12%

  • Facial injury
RR; 5.10 (95% 1.12–23.25)

1.7% vs 0.2%

More likely to

 

 

  • Achieve a vaginal birth

RR; 0.65 (95% CI 0.45–0.94)

91% vs 86% successful vaginal birth

No significant difference between instruments

  • Any neonatal injury
  • Low Apgar score (<7) at 5 minutes
  • Low pH (<7.2) in umbilical artery at birth

 

 


CI = confidence interval; RR = relative risk


During a first vaginal birth where instruments are used, medio-lateral episiotomy (with an incision angle of 60°) reduces the risk of a third or fourth degree tear. Tools to help ensure the correct angle of incision include special episiotomy scissors, such as Episcissors‑60, which may assist midwives and obstetricians achieve a post-suturing angle of 40–60°. The protective effect of episiotomy is highest when forceps are used, especially with a first time vaginal birth.

Additional planning is recommended in case a vaginal birth is not achieved with the first approach, and the risks of subsequent options should be considered (for example, sequential use of instruments or caesarean section at full dilatation).

Early discussion during pregnancy about these possible interventions may help prepare the woman should she face this situation. The discussion and her consent should be documented in her healthcare record.

For health service organisations

Ensure that policies, procedures and protocols include the management of instrumental vaginal birth, discussion with the woman about the possible benefits and risks associated with the available options and informed consent.

Ensure that conditions for a safe instrumental vaginal birth, as described in relevant clinical guidelines, are met within the facility, particularly with regard to availability of senior staff, facilities and back-up plans in case an instrumental birth is not successful.

Ensure that clinicians are appropriately trained and experienced to provide safe, high-quality care during an instrumental vaginal birth in accordance with professional standards, and are working within their scope of clinical practice. Ensure junior staff who do not have the requisite skills are supported by an experienced clinician.

Ensure that systems are in place to monitor variation in practice against expected health outcomes, as per Action 1.28 in the NSQHS Standards (2nd ed.), including rates of instrumental births and perineal trauma.

Provide timely feedback to clinicians on variation in practice and support them to review their clinical practice.

Record risks and the planned mitigation strategies in the risk management system.