The concept of IOL as ‘routine’ is a dangerous one; it should always be approached with caution. In women with particular risk factors, induction should not take place on an antenatal ward but on labour ward where the woman and baby can be more closely monitored. This is advisable for women with relevant risk factors including suspected fetal growth compromise, previous CS and high parity (NICE, 2001).

One of the less easily measurable risks of IOL may be the effect on a woman’s sense of control. Once she has initially consented to IOL, she may be offered little subsequent choice in continuing on to the next ‘inevitable’ procedure, leading to a cascade of interventions (Royal College of Midwives (RCM), 2005). Anxiety and loss of control may lead to increased stress levels which can have physiological consequences for labour (see Chapter 1). It must of course be remembered that prolonged pregnancy can also be stressful, so for some women induction actually gives them a sense of relief.

Other risks include the following:

• Membrane sweeping can cause minor bleeding but does not result in an increased incidence of membrane rupture or infection (NICE, 2001).
  
• Repeated vaginal examinations (VEs) can be painful, so perform them only when essential. Hibitane obstetric cream is not recommended for VEs as its chlorhexidine component can cause soreness.
  
• Whilst there is no conclusive evidence that prostaglandin-induced labour is more painful than spontaneous onset (NICE, 2001), some anecdotal accounts suggest otherwise. Prostin sometimes causes vaginal soreness (NICE, 2001). Intravenous (IV) oxytocin infusion appears to causes more painful contractions, perhaps due to their more intense onset, and as a result many women in this situation will opt for epidural anaesthesia.
  
• Hypertonic uterine contractions caused by oxytocics and/or prostaglandins can lead to fetal oxygen deprivation, uterine rupture and maternal and/or perinatal death (Smith et al., 2004). Close fetal and maternal surveillance is therefore essential. Induction and labour for women with high parity or previous CS carries a small but significant risk of uterine rupture even in the absence of hypertonic contractions (see Chapter 11).
  
• Response to prostaglandins and oxytocics is unpredictable, and midwives should observe women for tachycardia, nausea, vomiting, diarrhoea, water intoxication and headache (Hawkins, 2000).
  
• The CS risk evidence is controversial. Some studies suggest that IOL for uncomplicated post-term pregnancies increases the risk of CS delivery, length of hospital stay, use of epidural and non-epidural anaesthesia, neonatal resuscitation, neonatal intensive care unit admission and phototherapy (Seyb et al., 1999; Maslow& Sweeny, 2000; Boulvain et al., 2001). Cochrane meta-analysis (Gulmezoglu et al., 2006) and NICE (2001) however state that a policy of routine IOL for post-term pregnancies > 41/40 is associated with no difference in CS delivery compared with conservative management. The Royal College of Obstetricians and Gynaecologists (RCOG) (2001) suggests that the CS rate is in fact lower with IOL, and all agree there is no difference in use of epidural anaesthesia, instrumental delivery or fetal heart rate abnormalities.

Midwives will be familiar with the various methods of determining expected date of delivery (EDD). Consideration to the length of the menstrual cycle will enhance accuracy, and this is important in avoiding unintentional preterm IOL. Research shows that using ultrasound scan to calculate EDD results in fewer pregnancies considered postterm if the biparietal measurement is performed between 13/40 and 22/40 (Gardosi et al., 1997), but women may feel undermined if scan dates do not correspond to dates of which they are certain.

Some women may wish to be induced even though there are no medical or post-dates indications. Midwives should discuss the risks of early/unnecessary IOL, but where resources allow, maternal request for IOL at term may be considered when there are compelling psychological or social reasons and the woman has a favourable cervix. Social induction is unlikely to be supported if there are contraindications to IOL or staffing/resource issues.

NICE (2001) recommends offering induction beyond 41/40 for women with uncomplicated pregnancies, but compliance with this recommendation varies among trusts. Without IOL:

• by 40/40  58% will give birth
  
• by 41/40  74% will give birth
  
• by 42/40  82% will give birth

• at 37/40  1:3000
  
• at 42/40  3:3000
  
• at 43/40  6:3000

There is no current evidence to suggest that IOL before 41/40 improves fetal or maternal outcomes, but IOL after this time has been found to decrease rates of stillbirth and neonatal death in otherwise uncomplicated pregnancies (Hartman & King, 2001). Cochrane review by Gulmezoglu et al. (2006) concludes that there is only a very slightly increased perinatal mortality beyond 41/40 and states ‘the absolute risk is extremely small’ and that women should be counselled on both relative and absolute risks.

Premature rupture of membranes at term:

• Occurs in 6–19% of term pregnancies (NICE, 2001).
  
• 86% of women with PROM will go into spontaneous labour within 24 hours; the rate of spontaneous labour will then increase by 5% per day (NICE, 2001).
  
• NICE (2007) recommends IOL by 24 hours post-PROM.

Women induced after 24 hours were less likely than those managed expectantly to develop chorioamnionitis and endometritis, with no difference in instrumental or CS rates or adverse neonatal outcome (NICE, 2007). Neonatal infection rates were marginally reduced by early IOL in one study quoted by NICE. Women should be given information to make an informed choice on this issue; neonatal outcomes are not very different with either method (Dare et al., 2006).

The Bishop score is a subjective assessment of cervical ripeness for IOL that describes cervical effacement, consistency, position, dilatation and descent of the fetal presenting part. The score is determined by VE: a score of 6 or above viewed as favourable for IOL. Despite dilatation alone having been found to be a better determinate of successful IOL and vaginal delivery than the combined components of the Bishop score (Williams et al., 1997), it is still routinely used. Ultrasound scan has been shown to be of value in the prediction of successful IOL but is not widely used. (Rane et al., 2004).

Natural methods

Women seem open to natural methods of inducing labour once their due date has arrived. Most natural methods have had little research into their effectiveness, but anecdotal reports show varying levels of success. Natural methods include the following:

• Breast/nipple stimulation: Kavanagh et al. (2005) state that this appears effective in inducing labour and reducing postpartum haemorrhage but recommends caution in high-risk groups as the results can be dramatic.
  
• Sexual intercourse: this is a difficult and delicate area to study and research is so far inconclusive.
  
• Exercise, e.g. brisk walking.
  
• Eating spicy foods, e.g. curry.
  
• Eating fresh pineapple.
  
• Membrane sweeping.

NICE (2001) recommends membrane sweeping/stripping from term, a safe and effective method of reducing post-term pregnancy in low-risk women. The procedure is usually performed by a midwife who gently inserts a finger into the cervix and rotates it 360°, separating the membranes from the lower uterine segment. This aims to increase production of prostaglandins in the hope that amniotomy or oxytocic drugs can be avoided. Serial sweeping every 48 hours until labour commences results in consistent reduction in post-term pregnancy regardless of Bishop score (Boulvain et al., 2005). Women’s satisfaction is generally high despite the procedure’s discomfort, with most happy to accept it again in the future (de Miranda et al., 2006).

Complementary/alternative methods

Unless specifically trained in alternative methods, midwives would be wise to direct women to qualified practitioners, advising them to be cautious before using any of the methods discussed.

• Acupuncture/acupressure/moxibustion (this is also used for turning breeches)
  
• Reflexology
  
• Visualisation and meditation
  
• Hypnosis
  
• Herbal remedies
  
• Homeopathic remedies
  
• Castor oil

There are few studies into the above methods of IOL, but numerous websites and texts exist which explore their use.

Surgical/pharmacological methods

• Amniotomy or artificial rupture of membranes (ARM)
  
• Prostaglandin
  
• IV oxytocin

ARM

• ARM involves risk and constitutes a definite commitment to delivery. See Chapter 2 for risks, benefits and contraindications.
  
• There is insufficient evidence to recommend ARM alone as a method of IOL (Bricker and Luckas, 2007), so even if the cervix is sufficiently dilated to allow ARM, it is usually good practice to give at least one dose of prostaglandin first to ripen the cervix. However, many midwives believe that multigravid women with a high Bishop score may respond favourably to ARM alone, and this may prevent further intervention, so a decision should be made on an individual basis after discussion with the woman.
  
• CTG monitoring is not indicated, and water birth is not contraindicated following ARM induction once labour has been established if all else appears normal.
  
• ARM plus IV oxytocin within 1 hour results in a shorter latent phase of labour (Moldin and Sundell, 1996) although the optimal time interval between ARM and syntocinon is not clear.
  
• ARM is not automatically indicated following prostin if the woman is contracting and VE confirms progress.

Prostaglandins

• Prostaglandin (PGE2) vaginal tablets or gel soften or ‘ripen’ the cervix. Tablets are significantly cheaper and just as effective as gel (NICE, 2001).
  
• Oral prostaglandins have gastrointestinal side effects and lack evaluation casting doubts over their safety, so are rarely used (Hawkins, 2000).
  
• Prostaglandins given prior to ARM increase its effectiveness (NICE, 2001).
  
• Prostaglandin IOL alone results in a decreased incidence of operative delivery and an increased chance of delivery within 24 hours compared with oxytocin IOL alone (Enkin et al., 2000). The woman’s ability to remain mobile and upright in labour may play a part in this.
  
• Although misoprotol has been reported to be a safe and effective IOL drug (Surbek et al., 1997), it is not currently licensed for obstetric use. NICE (2001) and Gaskin (2001) suggest that certain risks have not yet been fully evaluated.

Oxytocin

• IV oxytocin (Syntocinon) is used to stimulate contractions if prostin and ARM have not achieved good labour progress.
  
• It should be administered via a controlled infusion pump/syringe driver with a non-return valve.
  
• Women who have had prostaglandins may respond dramatically to oxytocin and experience severe contractions (NICE, 2001). Continuous electronic fetal monitoring (EFM) is recommended during oxytocin induction to observe for uterine hypertonus, hypercontractility and/or fetal distress (NICE, 2001).

Although IOL is a significant intervention in the normal process of labour, the midwife can do much to support the woman in her wish for a normal birth. Once the reason for IOL is understood and all agree that it is desirable, it is important to ascertain the woman’s understanding of the process. Discuss how much she would actually like to know about the procedure (does she really want to see an amnihook?), and to provide further explanation and written information if necessary. The midwife should be aware that the woman may be in a high state of anxiety, especially if IOL is indicated for a fetal concern.

Midwives can give reassurance and explanations about the length of time it may take to get labour established, which may sometimes mean several days. If IOL has to be postponed after starting due to a busy labour ward, further explanation and support will be needed for both women and their birth partner/s. Midwives familiar with distressed women in antenatal beds who are well over their due dates and desperate to give birth recognise the need for sensitivity should this situation arise.

Partners and birth supporters should be included whenever possible so that all members of the ‘birthing team’ can work together to achieve a satisfying experience for the woman. Familiarisation with the birth setting, advice regarding suitable clothing, refreshment, meals and rest periods will enhance the experience. Where possible, the woman should not be separated from her support, and her midwife should give extra support if she is alone at any time.

Although usually done on delivery suite, IOL can be initiated on the antenatal ward alongside other women undergoing the procedure if there are no complications in the pregnancy (NICE, 2001).

General labour care applies as with spontaneous labour. Consent issues are just as important, and just because a woman has agreed to IOL, her consent for subsequent VEs and interventions is no less important. The midwife’s documentation should show evidence of a clear plan of care, progress of the labour and drugs used in the IOL process.

Midwifery care for starting IOL

• Review notes/history to ascertain EDD and rule out contraindications.
  
• Discuss the procedure with the woman and her partner(s) and gain consent. Make time to answer any questions and advise on coping mechanisms for ‘prostin pains’/early labour, such as warmed wheatgerm bag, a warm bath or going for a distracting walk.
  
• Ensure the IOL has been authorised and prostaglandin written up. Prostaglandins must be prescribed by a doctor. The midwife is responsible for ensuring the correct dose is administered safely.
  
• Ask woman to empty her bladder.
  
• Ensure the woman’s privacy.
  
• Commence CTG pre-procedure to ascertain fetal well-being.
  
• Assess cervix and explain Bishop score.
  
• Administer appropriate dose of prostaglandin or ARM depending on Bishop score. The gel/tablet is inserted into the posterior vaginal fornix at regular intervals; NICE recommends 6–hourly but the optimal time is unknown. Maximum recommended tablet dosage is 6 mg for all women. Maximum gel dosage is 4 mg for a nulliparous and 3 mg for other woman (NICE, 2001).
  
• Continue CTG until unequivocally satisfactory (typically 30–60 min), but once labour is established intermittent monitoring is recommended following prostaglandin IOL in the absence of other risk factors (NICE, 2001).
  
• Ensure maternal and fetal surveillance is implemented, should continuation of IOL be delayed.
  
• Women should be warned of side effects and advised to inform the midwife of symptoms such as very strong, frequent and painful contractions, sudden nausea and vomiting or if anything is worrying them.
  
• Intermittent FH monitoring is perfectly acceptable after initial CTG (NICE, 2001), and therefore labour in water is an option. It is sensible to ensure that labour is truly established first as early immersion can slow labour (see Chapter 7).
  
• Inform obstetrician if lack of progress or any problems.

Continuing IOL: care with IV oxytocin

If the woman has not established in labour, she will naturally feel disappointed: remember she may have had up to five doses of prostaglandin over several days and be tired and despondent. The next option to discuss is oxytocin, informing her she still has the option to decline. Women have occasionally been known to go home and return several days later in spontaneous labour or for further IOL.

• ARM is recommended prior to IV oxytocin if possible as it makes IOL much more effective (NICE, 2001).
  
• Ensure that oxytocin has been authorised and prescribed. It should not be started < 6 hours after prostaglandin due to the combined uterotonic effects (NICE, 2001).
  
• Discuss analgesia prior to commencing IV oxytocin as it is likely to be more painful: the woman may be happy to wait and see how she copes.
  
• Oxytocin regimes may vary among trusts but all must be monitored closely.