Introduction
With good labour support, most women will experience a spontaneous vaginal delivery. Some women, however, for a variety of reasons, will not. For those women the options are either an instrumental delivery or a caesarean section (CS). An instrumental delivery carried out competently, in a supportive atmosphere, can still be a triumph for a woman, and a source of celebration. However, there is an increased risk of morbidity and reduced maternal satisfaction with assisted delivery, particularly with a forceps delivery. Clinical competence is of course vital, but emotional support through assisted delivery is equally important.
Incidence and facts
- 11% of births in England were instrumental deliveries in 2005–2006 (National Health NHS, 2007).
- Ventouse is much preferred to forceps: it was used for only 17% of instrumental deliveries in 1989 but has risen in popularity to 63% in 2002–2003 (NHS, 2007).
- There are significant morbidity risks following instrumental delivery, but CS in second stage also carries high morbidity risk and has implications for subsequent births (Royal College of Obstetricians and Gynaecologists (RCOG), 2005).
Avoiding an instrumental delivery
The incidence of a forceps or ventouse delivery varies widely in different settings.Good labour practice is likely to reduce the incidence of instrumental delivery and will include the following:
- Continuous support in labour especially by a non-staff carer (Hodnett et al., 2004).
- Appropriate food and drink in labour (Johnson et al., 2000).
- Encouraging mobilisation/upright position (Gupta et al., 2004).
- Avoidance of epidural (Hodnett et al., 2004), although if instrumental delivery is performed, this is the most effective analgesia.
- Avoidance of continuous cardiotocograph (CTG) monitoring for low-risk women (National Institute for Health and Clinical Excellence (NICE), 2007).
- Avoidance of arbitrary second-stage time limits if progress is being made (Sleep et al., 2000). There is some evidence that maternal morbidity increases after 3 hours in the second stage (Cheung et al., 2004), but there is known maternal morbidity with instrumental delivery (Sleep et al., 2000; Dupuis et al., 2004).
- Use of intravenous (IV) oxytocin in a slow second stage, particularly for primigravidae with poor contractions (NICE, 2007).
- Delaying pushing for women with epidurals for 1–2 hours reduces mid-cavity or rotational deliveries (Roberts et al., 2004), and allowing up to 4 hours for second stage (NICE, 2007) and non-supine position increases the spontaneous delivery rate (Downe et al., 2004). There is no evidence that discontinuing an epidural for the pushing stage speeds delivery and it increases pain (Torvaldsen et al., 2004).
Indications for an instrumental delivery
- Failure to progress/maternal exhaustion in second stage. NICE (2007) guidance suggests that primigravida should be delivered within 3 hours of start of active phase, and a parous woman within 2 hours.
- Fetal distress (non-reassuring CTG, possibly in conjunction with fetal blood sample pH <7.20).
- Elective shortening of the second stage for fetal or maternal benefit (there are few absolute indications as obstetricians differ in their views on this subject).
Choice of instrument
Johanson and Menon (2002a) conclude that ventouse is the method of choice for assisted delivery because:
- A ventouse delivery is less likely to end in a CS, possibly due to the higher effectiveness of ventouse in, for example, the deflexed occipitoposterior position. However, some attempted ventouse deliveries will end in a forceps delivery.
- Forceps are more likely to succeed than ventouse, mainly because it is possible to pull harder.
- A ventouse birth causes fewer serious maternal injuries and fewer neonatal facial and cranial injuries. There are more reports of cephalhaematoma and retinal haemorrhage in ventouse births, but these do not appear to have long-term complications.
- No difference in 1-min Apgar score with a trend towards a lower 5-min Apgar score in ventouse births.
- A ventouse delivery may be difficult if there is marked caput, as suction may be hard to maintain. Following repeated fetal blood sampling attempts, ventouse may be inadvisable due to the risk of scalp trauma.
- Ventouse requires maternal effort. Some clinicians prefer forceps, or resort to them when ventouse fails.
NICE (2007) concludes that the decision should be made according to the clinical situation and the experience of the practitioner.
Care of a woman undergoing instrumental delivery
A calm and sensitive manner towards a woman undergoing instrumental delivery is crucial. Explanations need to be clear and informative, with plenty of support given to the woman and her birth partner(s), for whom such an experience may be a frightening ordeal.
Communication
Debating options at this stage of labour is not always easy. Some women may be feeling very much in control. Others may be exhausted, in extreme pain, and not receptive to discussion. If there are concerns about the condition of the baby, staff may feel under pressure to press on with an assisted delivery and limit debate. It is easy to talk glibly of ‘informed choice’; many distressed women in labour will consent to almost anything that offers them a way out.
Birth partners can feel extremely stressed and tired; they may display anger or aggression, as they try to cope with their own and the woman’s distress. It may be the partner, rather than the woman, who asks questions at this point. Conversely they may block discussion, saying ‘Just get on with it, she’s been through enough’.
Ensure that a woman is prepared for the possibility of CS, should the instrumental attempt fail.
Reducing fear
‘As fluorescent lights go on, the room fills with people, she hears the metallic clang of lithotomy poles, the sound of tearing paper as instrument packs are opened, the loud voices of people issuing instructions. She may feel disorientated, as the bed is pumped higher, she is tilted back, moved down the bed, legs uncomfortably suspended. As well as these sounds and sensations, she senses the anxiety levels of her attendants (there is something very dramatic about to happen here, so no matter how much pain I’m in now, it is about to get a whole lot worse)’ (Charles, 2002).
One obvious fact about instrumental deliveries is that they are frightening for women. Preferably one staff member should focus solely on the emotional needs of the woman and her birth partner(s). If another midwife is not available, this might be a maternity auxiliary/health care assistant.
Resist the urge to put all the lights on: a sudden flood of fluorescent light is frightening, increases the atmosphere of drama and may make a woman feel naked and vulnerable. Perineal illumination and ‘spot’ areas of lighting, where necessary, are quite sufficient.
The two most painful moments for the mother, apart from the birth itself, are the forceps blades/ventouse cup insertion and subsequent checking of the instrument’s position. Ensure that someone is there to prepare and support her through these painful procedures.
Analgesia
NICE (2007) recommends that instrumental birth should have tested effective analgesia. This is the woman’s decision, guided by professional advice. Some women would rather get the birth over with quickly, rather than wait for further analgesia. Theoretically, ventouse delivery pain is not significantly greater than from spontaneous birth, since the cup, unlike forceps, takes up no space alongside the head. Pain mainly results from initial cup insertion, followed by the usual delivery sensations. However, fear may increase pain perception.
- Epidural analgesia may be advisable for a forceps delivery. Ensure that it is adequately ‘topped up’ prior to delivery. Some doctors may instead administer a pudendal block.
- Some women may prefer to use entonox instead of, or in addition to, other methods of analgesia. Ensure that sufficient entonox has been inhaled prior to starting the procedure.
- Perineal lignocaine infiltration prior to ventouse cup insertion may help; there may also be a placebo effect from having given ‘something’ prior to the procedure.
- It is helpful to explain to a woman undergoing ventouse delivery that her urge to push is important, as this birth will be a collaboration.
- Some women may prefer to use entonox instead of, or in addition to, other methods of analgesia. Ensure that sufficient entonox has been inhaled prior to starting the procedure.
Use of IV oxytocin
If the contractions are weak, then oxytocin augmentation may considered. NICE (2007) cautions against oxytocin for the second stage, but does not give any rationale for this. It will be an individual clinical decision and local guidelines may apply. Oxytocin for other stages of labour is normally started low and increased gradually; but if used for instrumental delivery a fairly high dose of oxytocin is usually started immediately. This prevents time being wasted in gradually increasing the dose, and since the delivery is now imminent, any fetal effects are likely to be transitory.
Positioning
- Following explanations and consent, the woman’s legs should be gently and symmetrically lifted and supported in an adducted hip position. Lithotomy is not essential although some women may be comfortable in this position, particularly if staff experiment with pole height and adjust the position of the woman’s buttocks relative to the poles.
- It is quite possible to carry out an instrumental delivery with two helpers supporting the heels (Charles, 2002).
- For ventouse, other positions such as left lateral or squatting have been suggested (Johanson, 2001). Most professionals will prefer to apply the cup with the woman in a semi-recumbent position. Once applied, there is no reason why a woman should not take up a lateral or squatting position. Squatting is known to increase the pelvic outlet diameter. Having said this, many professionals are more comfortable working with the method they are accustomed to and may resist alternative suggestions.
- Think aortocaval occlusion. Often this is forgotten during instrumental delivery. Create a small lateral tilt from a wedge or pillow.
- It is quite possible to carry out an instrumental delivery with two helpers supporting the heels (Charles, 2002).
Bladder care
Most women produce little urine in the second stage and/or have difficulty micturating. Catheterisation was once routine prior to instrumental delivery. Vacca (1997) however states: ‘A catheter need only be passed if the woman is unable to void or if the bladder is visibly or palpably distended’. In the absence of substantial research, professionals should use clinical judgement or adhere to local protocol. An indwelling catheter should be removed or the balloon deflated before delivery (RCOG, 2005).
Episiotomy
This should not be a routine intervention performed with every instrumental delivery (Vacca, 1997; American Academy of Family Physicians (AAFP), 2004) or done simply to prevent a tear. An episiotomy is usually only indicated for severe fetal distress (Sleep et al., 2000; Hartmann et al., 2005), although as forceps take up space alongside the head, there may be an increased indication during a forceps delivery for access to apply forceps. A mediolateral rather than midline episiotomy appears to reduce third- and fourth-degree tears following forceps deliveries (Riskin-Mashiah et al., 2002; Viswanathan et al., 2005).
If indicated it should only be performed when the perineum has been stretched thin by the descending head. Clinical judgement should be exercised, taking into account the flexibility of the perineum. Early episiotomy increases maternal morbidity, blood loss and haematoma formation, extension to the anal sphincter or rectum, and postpartum pain (Sleep et al., 2000).
Consent for instrumental delivery should not imply that consent is given for epi- siotomy without further discussion.
Assisting at an instrumental delivery
Mutual staff support
Instrumental deliveries are stressful for everyone. Staff are often intimidated by the ‘medicalised’ atmosphere, but should try to avoid appearing rushed. Usually there is reasonable time to prepare. Even if the intervention is for fetal distress, remember that if this were a CS the time from problem diagnosis to delivery would be longer.
The doctor or midwife delivering the baby may appear calm but will be under pressure. Rudeness and roughness towards the woman, however, should not be tolerated. Positive attitudes and efficiency in opening packs, preparing equipment and communicating information will help ensure a safe birth and give the mother confidence in her helpers.
Interestingly, when asked who delivered their baby, 11% of women delivered by forceps and 40% by ventouse reported that both the doctor and the midwife delivered the baby: surely an example of teamwork (Redshaw et al., 2007).
Equipment preparation
Toan extent, this will depend on local practice:
- The vulva is cleansed and, usually, draped.
- Relevant sterile instrument packs are opened, and the delivering professional assisted, as requested.
- Incidence of shoulder dystocia and postpartum haemorrhage increases with instrumental delivery. Anticipate this and be prepared.
- For a ventouse birth, an assistant may need to attach the suction tubing to the machine and control the pressure. Leaks are usually due to poor tubing attachment or the release pedal having been left depressedfollowing apreviousdelivery.Soft cups are more likely to fail than metal cups butareless likelyto cause scalpinjury (Johanson & Menon, 2002b).
- There are single-use complete hand-held ‘Kiwi’ ventouse systems available which do not require a separate vacuum machine and can be operated by one person. Their size may make them appear less intimidating to the woman; however, there appears to be a higher failure rate compared to silastic and metal cups (Attilakos et al., 2005).
Instrumental procedure
Once packs are opened, the clinician normally performs a forceps delivery without further direct help.
For a ventouse delivery using a suction machine, the delivering professional gives instructions. Normally pressure starts at 0.2 kg/cm2 and then increases to 0.8 kg/cm2 in one step. There is no evidence that slowly increased pressure is of any benefit (Vacca, 1997).
The head should descend with each pull. The procedure should be abandoned if there is no evidence of progressive descent with each pull or if delivery is not imminent after three pulls by an experienced clinician (RCOG, 2005). AAFP (2004) suggests the procedure should be abandoned following three ventouse cup detachments or if there is no progress for three consecutive pulls. Experienced midwives and doctors often recognise when a head will not deliver after just one pull, and will abandon the attempt immediately. CS is then normally indicated.
Advocacy/accountability
Whilst the delivering professional is responsible for their own practice, midwives continue to have a duty of care towards their client and are still accountable for their practice. If a midwife feels that further analgesia is required, or that the delivering professional is having difficulties, they must speak out, acting as an advocate for the client. This is not an easy position to be in.
Post-procedure care
- A midwife should record any aspects of the birth, for example, start of procedure and fetal heart auscultation to ensure an optimal written record of events.
- Once the baby is born, if all is well, events should follow just as if the woman had delivered unaided; skin-to-skin contact and early breastfeeding should be encouraged in the normal way. Parents should be aware that the baby’s head may appear marked or moulded, but that this should disappear within hours.
- Diclofenac 100 mg given rectally (PR) following delivery/suturing is the drug of choice (Dodd et al., 2004). There is no evidence that prophylactic antibiotics reduce post-instrumental delivery infections (Liabsuetrakul et al., 2004).
Midwife instrumental delivery
Some midwives now carry out instrumental deliveries, following formal training and assessment, under specified criteria. Many midwives may be uncomfortable with the idea of midwife ventouse/forceps practitioners, feeling that it is a way of saving money and may erode the concept of a midwife’s involvement in normal birth (Davies & Iredale, 2006). Others suggest that a woman may get better care from a midwife (Charles, 1999; Alexander et al., 2002). Midwife ventouse practitioners have been successfully practising low-risk ventouse deliveries for over 10 years in the UK with good maternal and neonatal outcomes (Awala et al., 2006).
Do midwife practitioners bring anything special to instrumental birth?
Here are some speculations on how a midwife instrumental practitioner may improve a woman’s experience:
- Midwives have a philosophy of promoting normal birth, which means practitioners may not always rush to perform instrumental birth when asked, but make other practical, tested suggestions to facilitate a spontaneous birth.
- Midwives may be more aware of the importance of a relaxed birth environment, e.g. calm atmosphere, low lighting and minimal noise.
- They may use their awareness of a woman’s fear and loss of control to make the experience less stressful.
- They may be more likely to consider slow delivery of the head and selective (rather than routine) episiotomy, thus reducing perineal trauma.
- They may be more receptive than other clinicians to ideas such as ventouse in lateral or squatting positions.
Of course, none of the above will be true if the wrong kind of midwives become instrumental practitioners. Midwives are not mini-obstetricians. They should be recruited for training by midwives and selected for attitude as much as clinical skills. We do not need midwives who are by their nature interventionist or ‘drama queens (or kings)’.
Criteria for a midwife instrumental delivery
The criteria may vary according to local protocol.
- Fully dilated cervix.
- Occipitoanterior (OA) position (but not necessarily direct OA), well flexed.
- No asynclitism.
- Head no longer palpable (i.e. fully engaged) abdominally.
- Head below the level of the ischial spines.
- No/minimal caput or moulding.
- Good contractions.
- Verbal maternal consent obtained.
- If fetal distress occurs in a stand-alone midwife-only unitanda ventouse/forceps midwife is called in, it is sensible to call an ambulance as well.If thecircumstances are inappropriate for instrumental delivery, or the attempt fails immediate transfer is necessary.
Preparation
History
Review the antenatal and labour history, note parity; length of labour and fetal position during labour. Always beware of a slow 7–10 cm cervical dilatation interval. Slow second-stage progress, particularly in multigravidae, may indicate disproportion or malpresentation.
Assessment
An instrumental delivery should not be attempted unless the criteria given above are met. It is important to remain focused and analytical throughout, and not be swayed by the enthusiasm of other staff, or parents, to achieve delivery. It is particularly hard in stand-alone midwife-only units to decline an instrumental delivery because this means transfer to another unit. However, transfer following failed instrumental delivery, with the fetal compromise that may result, is worse.
An abdominal and a vaginal examination should be performed, with consent. Do not rely on the opinion of others, even if several staff reassure you that ‘It’s definitely OA . . . ’. Check for yourself.
Monitor the contractions; if poor strength and/or frequency, then IV oxytocin may be advisable.
Communication
Prior to physical examination, the midwife should introduce him/herself to the woman and partner. Attitude at this time is extremely important, and gaining a woman’s confidence is crucial. In cases of presumed fetal distress, this discussion may have to be brief, but most people understand and under such circumstances will want actions rather than words.
It is important to acknowledge the woman’s hard work so far. Explain the situation and confirm the woman’s (and her partner’s) understanding. Try to present options; for example, ‘If I confirm that the baby is in the right position for ventouse delivery, then we can either do it now, or see how your pushing goes over the next 15 minutes…’, giving the woman the choice. Some women, however, may be too distressed to make such choices, or may perceive this as indecision. Midwifery judgement should be used, as with all women in labour, to decide the level of information given.
Remember that most post-birth emotional trauma appears to be associated with poor information giving and perceived loss of control (Green, 1990). Never underestimate a woman’s capacity to make choices, however distraught she may appear.
Please read the preceding section entitled ‘Care of a woman undergoing instrumental delivery’for general comments on instrumental delivery, including analgesia, positioning and bladder care. The following section describes aspects specific to midwife ventouse or forceps delivery.
Midwifery ventouse delivery
Midwife ventouse deliveries are normally performed using silc, or hand-held plastic, cups. Check the suction by applying the cup to your hand. (See also the section entitled ‘Assisting at an instrumental delivery’ above.)
- Cup insertion is often painful, but with increasing experience, it can be performed smoothly and gently. Entonox may help.
- Immediately following a contraction (warn the woman what is about to happen), insert the squeezed, externally lubricated cup by gently slipping two fingers of the other hand into the introitus, retracting the perineum and sliding the cup into the space created.
- The cup is manoeuvred into the optimal position. Vacca (1997) describes the flexion point which, in a well-flexed OA position, is typically around 3 cm from the posterior fontanelle. This is the point of the vertex where the cup should be applied (see (Fig. 9.1).
- If the cup is correctly applied so that it lies over the flexion point, with the sagittal suture running centrally down, then traction will result in the smallest diameter of the fetal head (the suboccipitobregmatic and biparietal) being drawn through the birth canal (see also p. 122, Chapter 8, for diameters of the fetal skull). This minimises traction, thus increasing the likelihood of a successful birth and reducing trauma to mother and baby. In practice maternal tissue often inhibits cup positioning, so then the cup is simply placed as near as possible to the posterior fontanelle.
- The woman is often distressed following cup application, so reassure and congratulate her that the cup is now in place, and she has got through an unpleasant moment.
- Apply 0.2 kg/cm2 pressure, and then check the position and ensure that no maternal tissue is trapped in the cup. The process of feeling round the cup is another painful moment, especially anteriorly where space is tight, so warn the woman and proceed gently. If satisfactory, increase to 0.8 kg/cm2 in one step.
- Await the next contraction. Encourage the woman to get her breath back and focus on the coming need to push. Sometimes it helps to smile, get eye contact, and encourage an atmosphere of controlled excitement, ‘It really won’t be long now …’. This may recharge the atmosphere, giving the woman more energy. Beware though: a ‘high adrenaline’ environment may scare some women.
- With the contraction, encourage the woman to push and apply steady traction perpendicular to the cup. As the head comes under the symphysis and extends, the cup will rise from horizontal to almost vertical.
- As already discussed, it is not essential to perform an episiotomy for a ventouse delivery (Vacca, 1997; AAFP, 2004); clinical judgement should be exercised and consent obtained, as with any birth.
- Overexcited staff may be tempted to deliver the head quickly. Unless there is good reason to hurry, resist this urge. Remember how slowly a primigravid woman normally delivers; fast perineal stretching will cause increased pain and tissue trauma. Once the head is guided to the perineum, the woman’s expulsive urge may do most of the rest of the work. Some midwives will hardly pull at all, as the perineum slowly distends. Such births can be true collaborations between midwife and mother. There are reports of women who believe they had only minimal help (Charles, 1999) and deny they have truly had an instrumental delivery.
Fig. 9.1 Application of the ventouse cup. The cup is manoeuvred into the optimal position. In an occipitoanterior position the flexion point is typically around 3 cm from the posterior fontanelle with the sagittal suture running centrally down.
