Principles of intrapartum skills: Second-stage issues


Chapter 31

Principles of intrapartum skills


Second-stage issues



During the second stage of labour the baby descends and rotates through the pelvis, the symphysis pubis width increases (Rustamova et al 2009), contractions become expulsive, the perineum stretches and thins out, and the baby is born. This chapter will review the current evidence and clinical skills utilized during care in the second stage of labour and will include a discussion on the definition and duration of the second stage, the effects of directed and spontaneous pushing, different maternal positions and the management of a nuchal cord. The chapter concludes with a discussion on the ‘management’ of the perineum, including when and how to undertake an episiotomy.




Definition


Traditionally the second stage of labour has been defined by a very clinical description: from full dilatation of the os uteri to the complete birth of the baby. It is now recognized that this stage of labour has both a passive and an active phase (NICE 2014). Lai et al (2009) acknowledge there is more to the second stage than cervical dilatation, with descent of the presenting part and maternal feelings also being important considerations. Recognition of the passive phase is important so that the woman is discouraged from pushing as soon as the cervix is fully dilated, as this can have adverse outcomes.


The passive phase describes the time from when the cervix is fully dilated but there is no strong urge to push and the presenting part may still be high but is beginning to descend and rotate through the pelvis. It has been referred to as ‘rest and be thankful’, ‘rest and descent’ and the ‘pause for rotation’ (Brancato et al 2008, Long 2006). The woman may feel drowsy and relaxed (Long 2006) and the contractions may appear less frequent and strong, giving the woman the opportunity to recharge, ready for the active phase. Ideally the woman should be discouraged from pushing, allowing descent to occur passively to avoid maternal exhaustion. Yildirim & Beji (2008) claim women cannot push effectively when the urge to push is absent. Lai et al (2009) argue that the fetus will descend more rapidly once it is approximately 1 cm past the ischial spines and has rotated to an occipitoanterior position.


NICE (2014) state the active phase is when the woman experiences expulsive contractions, with a strong urge to push, the cervix is fully dilated, and the presenting part is visible. The urge to push begins with the initiation of the Ferguson’s reflex as the fetus descends past the ischial spines onto the pelvic floor stimulating the stretch receptors in the posterior vaginal wall. This causes the posterior lobe of the pituitary gland to secrete more oxytocin and a positive feedback mechanism is created. Lai et al (2009) suggest the reflexive need to push hard in the active phase is three-four times higher when there has been descent of the presenting part. If the woman is pushing when the cervix is fully dilated but expulsive contractions are absent, NICE (2014) suggest this should also be considered the active phase.


There are many advantages in delaying pushing until the active phase has been reached, including decreased maternal exhaustion; less perineal, bladder, and pelvic trauma; reduced incidence of instrumental delivery; increased self-belief and confidence in the woman’s ability to birth; fewer fetal heart abnormalities; higher Apgar scores at 1 and 5 minutes and higher umbilical cord arterial pH levels (Albers & Borders 2007, Brancato et al 2008, Lai et al 2009, Nicholl & Cattell 2006, Roberts & Hanson 2007, Schaffer et al 2005, Yildirim & Beji 2008).



Recognition


As women transition from the first to the second stage, a number of signs may be seen. The woman may become quiet and withdrawn or particularly vocal and feel that she ‘can’t go on’, ‘doesn’t want to do this anymore’. Equally she may feel renewed with energy. The Royal College of Midwives (RCM 2012a) suggest there may be changes in facial expression and the woman will begin to breathe harder. A heavy blood-stained show may be noted as the operculum descends and a change in the nature of contractions is felt with an overwhelming urge to push. There will be occasions when the urge to push does not signal the advent of the second stage, so if in doubt, undertake a vaginal examination (VE). The contractions may slow initially but then return stronger and are more expulsive in nature. As the presenting part descends, pouting of the vulva and anus may be seen and the presenting part will become visible at the introitus. Other physical signs include a purple line extending up the anal cleft (Hobbs 1998), changes in abdominal shape (Burvill 2002) or the sacral curve (rhombus of Michaelis; Sutton 2003). Equally, in the absence of visible signs and expulsive contractions, the passive phase of the second stage may be diagnosed following a VE when the cervix is noted to be fully dilated. This is essential when the breech is presenting to avoid head entrapment where the body is delivered through a partially dilated cervix that the head cannot pass through. A VE may also reveal the presence of a caput succedaneum that is giving the appearance of a descending presenting part.



Duration


While the RCM (2012a) advise there is no good evidence to justify arbitrary time limits on the length of the second stage of labour, NICE (2014) suggest the baby should be born within 3 hours (nulliparous women) or 2 hours (multiparous women) from the beginning of the active phase for most women. They advise referral may be required an hour before the end of these time limits. The importance of recognizing progress is also emphasized by NICE (2014); rotation and descent of the presenting part should be assessed if there is inadequate progress by 1 hour of active pushing for nulliparous women or 30 minutes for multiparous women, as a VE and amniotomy (Chapter 30) may be required.


Downe (2011) considers the second stage to be extremely variable and may be extremely quick, particularly for the multiparous woman. The length of the second stage will be affected by factors such as maternal position and epidural anaesthesia and the midwife should continue to observe for signs of normality and progress while recognizing and managing any deviations from normal. The American College of Obstetricians and Gynecologists suggest the second stage is prolonged if delivery has not occurred within 3 hours for nulliparous women with an epidural or 2 hours without and for multiparous women, within 2 hours with an epidural and 1 hour without (Laughon et al 2014). However, Gillesby et al (2010) found outcomes were better when women with an epidural delayed active pushing for 2 hours.


Cheng et al (2007) found a second stage lasting longer than 3 hours for multiparous women was associated with increased risk of operative delivery, increased maternal morbidity and lower Apgar scores. Allen et al (2009) found the risks of adverse outcomes for mother and baby increased when the duration of labour was longer than 2 hours for the multiparous woman and 3 hours in the nulliparous woman. A prolonged second stage is also associated with an increased incidence of postpartum haemorrhage (Lu et al 2009), chorioamnionitis, and third- and fourth-degree tears (Laughon et al 2014).



Pushing: spontaneous or directed


The RCM (2012a) remind us there is no good evidence for directed pushing using the Valsalva manoeuvre or that women need to be instructed on how and when to push. Women should be encouraged to follow what their bodies are telling them to do and push when they have the urge (NICE 2014). The verbal communication used during the second stage is vital so the woman is empowered and able to take control of the birth. Borders et al (2013) suggest this is achieved when the midwife uses affirmation, information sharing, direction (e.g. with changing position) and baby talk (talking to and about the baby). Delaying active pushing and waiting for the urge to push with descent of the fetus has been referred to as ‘labouring down’ (Borders et al 2013). During the active phase of the second stage, women develop a strong urge to push and will do so without instruction often once the contraction has built up rather than at the beginning of it (Hanson 2009). This form of physiological spontaneous pushing uses a resting respiratory volume, not a deep breath, and short pushes lasting 3–6 or 5–7 seconds, three to five times during a contraction (Borders et al 2013, Di Franco et al 2007, Perez-Botella & Downe 2006). Spontaneous pushing is not thought to significantly increase the duration of the second stage (Sampselle et al 2005); indeed it may even shorten it (Jahdi et al 2011, Yildirim & Beji 2008). Naranjo et al (2011) found the second stage was longer overall with spontaneous pushing; however, the amount of time spent physically pushing was less, resulting in fewer adverse outcomes than women who experienced directed pushing. Gillesby et al (2010) had similar results when women with an epidural delayed pushing. With less time spent pushing, Lai et al (2009) found women who pushed spontaneously experienced less fatigue at 1 and 24 hours post-delivery.


Directed pushing generally involves taking a deep breath and holding it, taking breaths quickly between pushes and 3–4 sustained pushes from when the contraction begins to when it ends. This is the Valsalva manoeuvre that was originally used to clear pus from the middle ear. It causes the glottis to close and increases intrathoracic pressure which decreases venous return to the heart resulting in reduced cardiac output and blood pressure. This can result in reduced uterine blood flow and placental perfusion increasing the likelihood of the fetus becoming hypoxic and acidotic (Perez-Botella & Downe 2006, Prins et al 2011, Roberts & Hanson 2007). This may also be a factor involved with perineal trauma and stress incontinence due to the increased downward stress on the anterior vaginal wall and bladder supports (Prins et al 2011, Roberts & Hanson 2007, Schaffer et al 2005). The woman may feel dizzy from holding her breath which may cause her to gasp, allowing a sudden increase in the amount of blood returning to the heart and increasing blood pressure (Dempsey et al 2014, Perez-Botella & Downe 2006). Using the Valsalva manoeuvre can also result in a temporary reduction in vision and subconjunctival haemorrhage, which can occur as a result of transient subclinical retinal oedema (Connor 2010). Women may experience more fatigue up to 24 hours post-delivery, which can indirectly affect the physical and mental health of the new mother (Lai et al 2009).


In situations where the woman does not experience the urge to push (e.g. epidural anaesthesia) she may need some instruction on when and how to push (Osborne & Hanson 2012). The principles of spontaneous pushing should be followed, for example, no breath holding, short bursts allowing the contraction to build up first.



Position


The position adopted by women during the second stage of labour is influenced by many factors, including cultural and societal norms. Meyvis et al (2011) suggest the two major positions are horizontal and vertical (upright). Within many of the Western countries a semi-recumbent position with legs on a support has been commonplace which Meyvis et al (2011) and Gupta et al (2012) suggest is to allow a good view of the perineum and facilitate manoeuvres such as assisted delivery. De Jonge et al (2007) consider routine use of the supine position as an intervention when used in normal labour. In traditional cultures the vertical position is often the position of choice (Gupta et al 2012). While there may be advantages and disadvantages with each of the different positions Gupta et al (2012) and Kemp et al (2013) consider women should be able to deliver in whichever position is comfortable for them (even with an epidural in situ) and given the choice, women do opt to use a variety of positions during the second stage (De Jonge et al 2007, Kemp et al 2013). Women should also be aware of the positive and negative effects of upright and horizontal positions to enable them to make an informed choice. Women who are able to choose and change positions appear to have a greater sense of control and less need for analgesia (Lawrence et al 2013). NICE (2014) agree women should be encouraged to use whichever position they choose but advise they should be discouraged from lying supine or semi-supine. The midwife has an important role in encouraging women to use different positions and supporting women in their choice. This is particularly important if a VE is performed during the second stage as De Jonge & Lagro-Janssen (2004) found women were more likely to remain supine following the VE. A positive and supportive environment can promote a sense of competence and personal achievement (Gupta et al 2012). Cotton (2010) argues that a comfortable position will facilitate beta-endorphin production, thus enhancing analgesia at this time.


Sanderson (2012) suggests the pelvis should be viewed as a dynamic structure during birth and recommends a ‘sacrum-free’ position for delivery to make use of the increased pelvic diameters. In 1969, Russell demonstrated an increase in both the transverse and anteroposterior diameters when the woman is in a squatting position (Russell 1969) and, according to Sutton (2003), pelvic diameters also increase when the woman adopts a lateral position. These suggest horizontal positions should be avoided where possible.


Horizontal positions include lithotomy, semi-recumbent (sitting, semi-sitting) and left lateral (although it could be argued lateral positions are similar to vertical as there is no pressure on the sacrum). When the woman is sat on her pelvis and the sacrum is unable to move, the pelvic diameters of the outlet are reduced. The woman may attempt to lift her buttocks off the bed, push her pelvis forwards and throw her arms back to rectify this (Downe 2011), although this practice is often discouraged unnecessarily. Downe (2011) suggests this is the opposite of the commonly encouraged semi-recumbent position with the woman holding onto her thighs to pull her legs towards her and suggests it is more logical to allow the woman to follow her instincts. Bayes & White (2011) found lithotomy was used more when an instrumental delivery was anticipated and argue this should be the only reason for its use as it is associated with an increased risk of third- and fourth-degree tears (Gottvall et al 2007). The lithotomy position is less likely to empower the woman and may be embarrassing for her as it can feel as if her genitals are on display with everyone looking down at her (De Jonge & Lagro-Janssen 2004). When a semi-recumbent position is used, Downe (2011) recommends the woman is well-supported by pillows and or a wedge to prevent her sliding into a dorsal position.


Vertical or upright positions include standing, squatting, also kneeling and all-fours. Upright positions are thought to encourage descent of the presenting part, strong, efficient contractions, enhanced alignment of the fetus and assist the fetal ejection reflex (Cotton 2010). Pearson (2012) also claims the second stage is shorter, with fewer instrumental deliveries and fetal heart abnormalities when an upright position is adopted.


Perineal damage includes spontaneous first- to fourth-degree tears and episiotomy, but does the position adopted affect the likelihood of this occurring? Meyvis et al (2011) compared lithotomy with the left lateral position and found perineal damage increased with the use of the lithotomy position. This appears to be due to more episiotomies, but women in the left lateral group had significantly more first- and second-degree perineal tears. Gupta et al (2012) suggest an upright position or use of the birthing stool is associated with fewer episiotomies but an increased risk of second-degree tears occurring. However, Albers & Borders (2007) found upright and lateral delivery positions were associated with fewer perineal tears. When using a semi-sitting position during the expulsive phase, Da Silva et al (2012) found an increased risk of second-degree tears and episiotomy compared to women who adopted a lateral, squatting or all-fours position. Soong & Barnes (2005) found a significant increase in perineal trauma in women adopting the semi-recumbent position compared with the all-fours position. These effects were more noticeable with women undergoing their first vaginal birth and where the birth weight was in excess of 3500 g. Women with epidural anaesthesia are more likely to adopt a horizontal position; for these women, Soong & Barnes (2005) found suturing was more likely to be required in a semi-recumbent rather than a lateral position. Nicholl & Cattell (2006) agree, suggesting if a horizontal position is used for delivery, a lateral position is preferable, as it results in more intact perineums and less risk of fourth-degree tears. De Jonge et al (2010) compared sitting, semi-sitting, and recumbent positions and found similar rates of intact perineums but more perineal tears with the sitting group and more labial tears with the semi-sitting group. Gottvall et al (2007) found there was a greater risk of third- and fourth-degree tears when women were in lithotomy (regardless of mode of delivery) or squatting.


Blood loss may increase in the presence of perineal tears or episiotomy but there is little evidence to suggest blood loss increases with one or more particular positions. Gupta et al (2012) did find a greater blood loss >500 mL associated with an upright birthing position but also noted the blood loss was collected in a receptacle; thus it could be measured rather than inaccurately estimated, and there were no differences in the rate of blood transfusions required.


Di Franco et al (2007) consider upright positions make use of gravity and increase the pelvic diameters but acknowledge they are more tiring than semi-recumbent positions. To counteract this, they recommend using a supported squat, supporting the woman under her arms. This results in less weight on her legs and feet, and lengthening of her trunk, which provides more space for the fetus to move through the pelvis.


When comparing the use of kneeling and sitting upright, Ragnar et al (2006) concluded the outcomes do not differ significantly, although kneeling was associated with more favourable maternal experiences and reduced pain. Kneeling also allowed women the freedom to modify their position more easily, allowing them to feel more in control.


When adopting a supine, semi-recumbent or prolonged squatting position, it is important to avoid excessive and prolonged thigh-holding, as this can cause compressive peroneal neuropathy (functional and/or pathological changes to the peroneal nerve which supplies the calf and foot). This presents with knee tenderness, foot drop, and decreased sensation over the dorsum of the foot (Sahai-Srivastava & Amezcua 2007).


Midwives should therefore:


Oct 17, 2016 | Posted by in MIDWIFERY | Comments Off on Principles of intrapartum skills: Second-stage issues
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