C H A P T E R 1 6 Physiology and care during the first stage of labour

1. C H A P T E R 1 6 Physiology and care during the first stage of labour

2. Defining labour A human pregnancy is considered to last approximately 40 weeks, with labour usually occurring between 37 and 42 weeks' gestation (National Institute for Health and Clinical Excellence [NICE] 2007). Labour, purely in the physical sense, may be described as the process by which the fetus, placenta and membranes are expelled through the birth canal;

3. The World Health Organization (WHO) defines normal labour as one that is low risk throughout, spontaneous in onset with the fetus presenting by the vertex, culminating in the mother and infant being in good condition following birth (WHO 1999). labour where the fetus is presenting by the breech with no other risk factors should also be considered normal (Burvill 2005). Furthermore, all definitions of labour appear to be purely physiological and do not encompass the psychological wellbeing of the woman.

4. stages of labour The first stage of labour is usually recognized by the onset of regular uterine contractions, an accompanying effacement and at least 4 cm dilatation of the cervix and finally culminates in full dilatation of the cervix. First stage consist of : the latent, is prior to the active phase stage of labour and may last 6–8 hours in primigravidae when the cervix dilates from 0 cm to 4 cm dilated active This begins when the cervix is at least 4 cm dilated and, in the presence of rhythmic contractions, progressively dilates to 10 cm or full dilatation. transitional phases, the cervix is around 8 cm dilated until it is fully dilated or until expulsive contractions associated with the second stage of labour are felt by the woman.

5. second ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, third stage,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

6. The onset of spontaneous physiological labour • The onset of labour is determined by a complex interaction of maternal and fetal hormones and is not fully understood. • It would appear to be multifactorial in origin, being a combination of hormonal and mechanical factors. • Increase level of oestrogen during the last weeks of pregnancy, resulting in changes cause uterine muscle fibres to display oxytocic receptors and form gap junctions with each other. Oestrogen also stimulates the placenta to release prostaglandins. • Uterine activity may also result from mechanical stimulation of the uterus and cervix as • Overstretching • pressure from a presenting part on the cervix.

7. Recognition of the onset of labour The onset of labour is a process, not an event; therefore it is very difficult to identify exactly when the painless (sometimes painful) contractions of pre-labour develop into the progressive rhythmic contractions of established labour. It is part of the role of the midwife to ensure that women have sufficient information to assist them in recognizing the onset of established labour. This information is also needed to enable women to make informed choices based on current and unbiased evidence. The complex physical, psychological and emotional experience of labour affects every woman differently and midwives must have sound knowledge and experience to enable the woman to maintain control over the birth of her baby.

8. Ways to enable the woman to maintain birth control • Women in labour should be encouraged to trust their own instincts. • Women should listen to their own body and verbalize their feelings. • Support & reassurance should be given and discussion of this potential situation earlier in the pregnancy can enable the woman and her partner to prepare for labour more effectively. • Contact with the midwife should be made when regular, rhythmic, uterine contractions are experienced, and these are perceived by the woman as uncomfortable or painful.

9. Physiology of the first stage of labour Duration The length of labour varies widely and is influenced by parity, birth interval, psychological state, presentation and position of the fetus. Maternal pelvic shape and size and the character of uterine contractions also affect timescale. Over the years there has been much debate surrounding the length of physiological active labour in low-risk populations of childbearing women. cervical dilatation occurred at the rate of 1 cm per hour (Albers 1999;Lavender et al 2006;Zhang et al 2010). A cervical dilatation rate of 0.5 cm per hour, however, has now been incorporated into the NICE (2007)intrapartum guidelines as being within the parameters of normal labour.

10. Cervical effacement Effacement refers to the inclusion (taking up) of the cervical canal into the lower uterine segment. the segment and the cervix merges into the lower uterine segment. The cervical canal widens at the level of the internal os, whereas the state of the external os remains unchanged (Cunningham et al 2010) (Fig. 16.1).

11. Effacement may occur late in pregnancy, or it may not take place until labour begins. In the nulliparous woman the cervix will not usually dilate until effacement is complete, whereas in the multiparous woman, effacement and dilatation usually occurs simultaneously and a small canal may be felt in early labour.

12. Cervical dilatation Dilatation of the cervix is the process of enlargement of the os from a tightly closed to an opening large enough to permit passage of the fetus. Dilatation is assessed in centimeters and full dilatation at term equates to about 10 cm. However, acknowledging that all women are different sizes and shapes means that full cervical dilatation may be between 9 and 11 cm in individual women (Walsh 2012). Dilatation occurs as a result of uterine action and the counter-pressure applied by either the intact bag of membranes or the presenting part, or both. A well-flexed fetal head closely applied to the cervix favors efficient dilatation. Pressure applied evenly to the cervix causes the uterine fundus to respond by contraction and retraction, referred to as the Ferguson reflex

13. Uterine action Fundal dominance Each uterine contraction commences in the fundus near one of the cornua and spreads across and downwards.

14. Polarity Polarity is the term used to describe the neuromuscular harmony that prevails between the two poles or segments of the uterus throughout labour. During each uterine contraction, these two poles act harmoniously. The upper pole contracts strongly and retracts to expel the fetus; the lower pole contracts slightly and dilates to allow expulsion to take place. If polarity is disorganized then the progress of labour is inhibited.

15. Contraction and retraction Uterine muscle has a unique property. During labour the contraction does not pass off entirely, as muscle fibres retain some of the shortening of contraction instead of becoming completely relaxed This is termed retraction. This process assists in the progressive expulsion of the fetus, such that the upper segment of the uterus becomes gradually shorter and thicker and its cavity diminishes.

16. Intensity and resting tone Each labour is individual and does not always conform to expectations, but generally before labour becomes established, uterine contractions may occur every 15–20 minutes, lasting for about 30 seconds. They are often fairly weak and may even be imperceptible to the woman. The contractions usually occur with rhythmic regularity and the intervals between them where the muscle relaxes (resting tone) gradually lessen while the length and strength gradually intensifies through the latent phase and into the active phase of the first stage of labour. By the end of the first stage, the contractions may occur at 2–3 minute intervals, last for 50–60 seconds and are very powerful

17. Formation of upper and lower uterine segments By the end of pregnancy, the body of the uterus is described as having divided into two segments, which are anatomically distinct (Fig. 16.4). The upper uterine segment, having been formed from the body of the fundus, is mainly concerned with contraction and retraction, and is thick and muscular. The lower uterine segment is formed of the isthmus and the cervix, and is about 8–10 cm in length. The lower segment is prepared for distension and dilatation.

19. The retraction ring A ridge develops between the upper and lower uterine segments, known as the retraction ring (Fig. 16.5). The physiological retraction ring gradually rises as the upper uterine segment contracts and retracts and the lower uterine segment thins out to accommodate the descending fetus. Once the cervix is fully dilated and the fetus can leave the uterus, the retraction ring rises no further. However, in extreme cases of mechanically obstructed labour, this physiological retraction ring becomes visible above the symphysis pubis and is described as Bandl's ring. A Bandl's ring may consequently be associated with fetal compromise

21. Show As a result of the dilatation of the cervix, the operculum, which formed the cervical plug during pregnancy, is released. The woman may observe a bloodstained mucoid discharge a few hours before, or within a few hours after, labour commences. The blood comes from ruptured capillaries in the parietal decidua where the chorion has become detached from the dilating cervix and should only be a staining (Impey and Child 2012 , a small loss of bright red blood referred to as a show.

22. Mechanical factors Formation of the forewaters and hindwaters As the lower uterine segment forms and stretches, the chorion becomes detached from it and the increased intrauterine pressure causes this loosened part of the sac of fluid to bulge downwards into the internal os, to the depth of 6–12 mm. The well-flexed fetal head fits snugly into the cervix and cuts off the amniotic fluid in front of the head from that which surrounds the body, forming two separate pools of fluid. The former is known as the forewaters and the lafer, the hindwaters. In early labour it is often possible to feel intact forewaters bulging even when the hindwaters have ruptured, making ruptured membranes a difficult diagnosis at times.

23. General fluid pressure While the membranes remain intact, the pressure of the uterine contractions is exerted on the amniotic fluid and, as fluid is not compressible, the pressure is equalized throughout the uterus and over the fetal body, known as general fluid pressure (Fig. 16.6). When the membranes rupture and a quantity of fluid emerges, the fetal head, the placenta and umbilical cord are compressed between the uterine wall and the fetus during contractions with a consequential reduction in the oxygen supply to the fetus. Preserving the integrity of the membranes, therefore, optimizes the oxygen supply to the fetus and also helps to prevent intrauterine and fetal infection (Howie and Rankin 2010).

24. Rupture of the membranes The optimum physiological time for the membranes to rupture spontaneously is at the end of the first stage of labour, after the cervix becomes fully dilated and no longer supports the bag of forewaters. The membranes may sometimes rupture days before labour, in most cases there is no apparent reason for early spontaneous membrane rupture. Early rupture of membranes may lead to an increased incidence of variable decelerations on (CTG), resulting in an increase in caesarean sections if fetal blood sampling is not available . All women are required to give consent for this intervention and the midwife should have a clear indication for performing an ARM: details of which should be recorded in the woman's labour records (Nursing and Midwifery Council [NMC] 2009,2012).

25. Fetal axis pressure During each contraction, the uterus rises forward and the force of the fundal contraction is transmitted to the upper pole of the fetus, down the long axis of the fetus and applied by the presenting part to the cervix. This is known as fetal axis pressure (Fig. 16.7) and becomes much more significant after rupture of the membranes and during the second stage of labour.

26. Recognition of the first stage of labour Education during pregnancy is important to enable the woman to recognize the beginning of labour and understand the latent phase in order to consider possible strategies she may use for labour and birth. Women should appreciate that in late pregnancy vaginal secretions without any bloodstaining increase. In addition, they should be aware that a show, which is usually a pink or bloodstained jelly-like loss, prior to the onset of labour or in early labour, is quitecommon. If a woman is examined vaginally in late pregnancy they should also be informed that there may be some slight blood loss after the procedure. Braxton Hicks contractions are more noticeable in late pregnancy and some women experience them as painful. In active labour, contractions exhibit a pattern of rhythm and regularity, usually increasing in length, strength and frequency as time goes on.

27. When the woman first feels contractions she may be aware only of backache, but if she places a hand on her abdomen she may perceive simultaneous hardening of the uterus. If the pregnancy has no problem, with a normal birth anticipated, the midwife should advise the woman to stay in her own surroundings, continue with her normal activities, to eat, be active and upright. It is sometimes difficult to be certain whether or not the membranes have ruptured spontaneously prior to labour or in early labour. The woman may be experiencing some degree of stress incontinence, so she may be unsure if it is liquor or urine that she is passing. If there is any doubt, the woman should contact her midwife who may decide to insert a speculum into the vagina to observe for any amniotic fluid. Digital examination should be avoided if the woman is not in labour as it can increase the risk of ascending infection (Shepherd et al 2010).

28. Initial meeting with the midwife Ideally, the woman should know her own midwife and be able to contact her when labour starts. Where this is not possible, it is crucial that the first meeting between the midwife, the labouring woman and her partner is very important. If the woman is planning to birth in hospital, she may worry about the reception she and her companion will receive and the atitude of the people there. In addition, an unfamiliar environment may provoke feelings of vulnerability and undermine her confidence. Comfortable surroundings, a welcoming manner and a midwife who greets the woman as an equal in a partnership will engender feelings of mutual respect, thus enabling the woman to relax and respond positively to the amazing forces of labour and to her baby aher it is born (Berry 2006; Fisher et al 2006; Raynor and England 2010).

29. The language of childbirth It has been recognized that some of the childbirth terminology used when communicating with women appears medical not clear to women. The terms pain and labour are suggestive of difficulty and trouble. It is therefore vital the midwife observes what she says to women during childbirth and uses appropriate and adapted language which is woman-friendly. The word delivery has been replaced by the term birthing or birth as these appear more suitable when discussing the concept and practice of normality within midwifery.

30. Communication The key issues for women relate to achieving a safe birth, feeling in control within the birth environment, developing supportive relationships with their carers, and being treated with kindness, respect, dignity and cultural sensitivity if they are to realize apositive experience of birth. Effective communication between the midwife and the woman and her partner, and with other clinicians in the multidisciplinary team, is essential to providingeffective safe supportive care in labour and achieving the woman's objectives. Communication does not consist only of the content of what is said, but also includes non-verbal communicationand written records, such as the woman's birth plan. Poor communication is the commonest cause of preventable adverse outcomes inhospitals and remains a significant cause of writen complaints.

31. Interpreting services If the woman and midwife are unable to understand each other, communication will be ineffective and it is essential that adequate interpretation services are available when necessary. Although there is a tendency to rely on family members or friends to provide interpreting services, the use of such interpreters is deemed inappropriate when the midwife wishes to discuss sensitive issues such as past history, domestic abuse or the need for interventions. Wherever possible, professional interpretation services (axcess) should beprovided for all non-English-speaking women. If a face-to-face interpreter cannot be obtained, then the use of a telephone or Internet interpretation service should be considered.

32. Birth plan Regardless of where the woman plans to give birth, a birth plan is a valuable tool for midwives to observe and use to facilitate the provision of holistic, individualized care. The birth plan therefore provides the opportunity for the midwife to discuss with each woman and her partner any plans about the type of birth they would like that they may have already prepared with support from their community midwife. An outline may be present in the case notes, or the couple may bring a birth plan with them. Frequently, the partner is involved in this forward planning, which should be a flexible proposal that can be reviewed and revised as labour progresses (Department of Health [DH] 2007). Some women, however, may not have prepared a birth plan and so the midwife should encourage them to consider any preferences that they may have, for example:

33. example: • her choice of birth companion(s). • her choice of clothes for labour. • ambulation and fetal monitoring (intermittent, electronic or a combination). • strategies for labour (water immersion, massage, pharmacological pain relief). • position for labour and birth. • cutting of the umbilical cord. • skin-to-skin contact and feeding the baby after birth. • Having the opportunity to discuss such issues in early labour enables the establishment of a trusting relationship between the woman and the midwife to develop where the woman feels valued and involved in intrapartum decision-making: all details of which should be clearly documented in the intrapartum records

34. Emotional and psychological care When a woman begins to labour, she may have a mixture of emotions. Most women anticipate labour with a degree of excitement, anxiety, fear and hope. Many other emotions are influenced by cultural expectations and previous life experiences. The state of the woman's knowledge, her fears and expectations are also influenced by her companions during labour, including the attitude and behavior of the caregiver. By the time labour starts, a decision will already have been reached about where the woman plans to give birth. Some women may choose to give birth at home, some in a midwife-led unit/birthing center and others in hospital. Some women may also wish to labour as long as possible at home but give birth in hospital. Whatever choice the woman makes, she must able to feel she is in control of what is happening and contributing to the decisions made about her care.

35. The concept of continuous support in labour There is evidence that the presence of the midwife and one-to-one personal affection is positively associated with a woman's satisfaction with her care. Kennedy et al (2010) describe that the presence of the midwife can enhance the woman's trust in her own ability to cope. In a systematic review by Hodnef et al (2011), the value of continuous support during labour and birth is clearly evident. The review, consisting of 21 randomized clinical trials, involving over 15 000 women, showed evidence that women who laboured with continuous support had shorter labours and were less likely to experience intrapartum interventions. These women were also less likely to have an epidural or other forms of pain medication, give birth by caesarean section, ventouse or forceps and consequently appeared more satisfied with their overall experience of childbirth (Hodnef et al 2011).

36. Reducing the risk of infection In the latest Confidential Enquiries into Maternal Deaths report, the leading cause of direct deaths during the triennium 2006–2008, was sepsis, accounting for 26 deaths (Harper 2011). Hand hygiene, the combination of processes including hand washing, the use of alcohol hand rub and carefully drying and caring for the skin and nails, is considered to be the single most important measure in preventing the spread of infection. A clean environment is essential if infection rates are to be kept to a minimum and the midwife has an important role to play in ensuring that all equipment is cleaned according to local Trust guidelines and that there is adherence to all infection control measures. Rooms, birthing pools, beds and any equipment used by the midwife should be effectively cleaned before use. When a woman is admitted to hospital, invasive procedures should be kept to a minimum as, such as the performance of vaginal examinations ,intravenous fluids, repeated vaginal examinations, epidural analgesia and fetal blood sampling, all of which will increase the risk of infection.

37. The midwife's initial physical examination of the woman The initial examination should include a discussion with the woman about when labour commenced, whether the membranes have ruptured and the frequency and strength of the contractions. The midwife should be aware that the woman will be very conscious of her body and may be unable to concentrate on the conversation or respond while experiencing a contraction. Since the woman has embarked on an intensely energy- demanding process, enquiry should be made about her ability to sleep and her most recent intake of food. If she is in early labour and there are no concerns about the pregnancy, the woman should be advised she can eat and drink as she wishes, remain mobile and maybe bathe if she would find this relaxing. Consideration should be given to the woman's social circumstances, including the care of other children and whether a birthing partner is available and has been contacted.

38. Past history • Of particular relevance at the onset of a woman's labour are: • the contents of the birth plan. • her parity and age. • the gestational age and outcomes of previous labours. • the weights and condition of previous babies. • her blood results including grouping, Rhesus factor and haemoglobin • her attendance at any specialist clinics. • evidence of any known problems: social or physical.

39. Consent Prior to touching the woman, a sound explanation of the proposed examination and their significance should be given. Verbal consent should be obtained and recorded in the notes (NMC 2008, 2009). The midwife must be aware that a competent woman, with a capacity to make decisions, is within her rights to refuse any treatment regardless of the consequences to her and her unborn baby and does not have to give a reason (DH 2009). Should the midwife be providing care to a pregnant teenager under the age of 16 years, it is important to carefully assess whether there is evidence that she has sufficient understanding in order to give valid consent, i.e. complies with the Fraser guidelines, previously referred to as being Gillick competent (Gillick v West Norfolk and Wisbech AHA 1986; GMC 2013).

40. General assessment Basic observations, including pulse rate, temperature and blood pressure, are assessed and recorded. The woman's hands and feet are usually examined for signs of oedema. Slight swelling of the feet and ankles is physiological, but pre-tibial oedema or puffiness of the fingers or face is not.A detailed abdominal examination , partogram, fetal heart rate should be auscultated for a minimum of 1 minute immediately after a contraction using a Pinard stethoscope and the rate should be recorded as an average, in a single figure.A vaginal examination (VE) may also be undertaken to help confirm the onset of labour and determine the extent of cervical effacement and dilatation (Fig. 16.8), with some women requesting it when seeking reassurance about the status of their labour.

41. Records The midwife's record of labour is a legal document.The records may be examined by any court for up to 25 years, Records should be as contemporaneous as possible. Each entry should be authenticated with the midwife's full signature with the name printed underneath. Records should be comprehensive but concise and consist of the woman's observations, her physical, psychological and sociological state, and any problem that arises as well as the midwife's response and any subsequent interventions. The records should be kept in chronological order as their accuracy provides the basis from which clinical improvements, progress or deterioration of the woman or fetus can be judged. The record is shared between the midwife and obstetrician The obstetrician is also responsible to record their findings. The midwife usually enters in the records the summary of labour and initial details about the health of the baby. A midwife must ensure all records are stored securely and should not destroy or arrange for their destruction.

43. The charts are usually designed to allow for recordings at 15-minute intervals and include: fetal heart rate maternal temperature, pulse and blood pressure frequency and strength of contractions every 10 minutes descent of the presenting part cervical effacement and dilatation colour of amniotic fluid degree of caput succedaneum/moulding fluid balance urine analysis drugs administered.

47. Subsequent care in the first stage of labour Assessing progress Physical examination of the cervix is not the only way to assess labour. Midwives can use a range of skills, including visualization of the purple line, appearing from the woman's anal margin gradually extending to the nape of the bufocks (Hobbs 1998; Shepherd et al 2010), and observing the Rhombus of Michaelis, a kite-shaped area between the sacrum and ilea which becomes increasing visible as the fetal head descends in the pelvis (Shepherd et al 2010). In addition, the midwife should be alert in observing for changes in the woman's breathing, behaviour, noises, movements and posture alongside changes in the nature of contractions.

48. Abdominal examination An abdominal examination should be repeated by the midwife at intervals throughout labour in order to assess the length, strength and frequency of contractions and the descent of the presenting part. Palpation is of benefit prior to undertaking a vaginal examination, as the findings will assist the midwife to be accurate when defining the position and station of the head/breech. It is also useful to record the position of the fetus contemporaneously during the labour, as this can assist with the analysis of events should a shoulder dystocia occur.

49. Contractions The frequency, length and strength of the contractions should be noted and recorded on the partogram, usually at 30 minute intervals. The uterus should always feel softer between contractions and failure to relax is evidence of hyper tonicity that is usually defined as a contraction lasting more than 2 minutes (NICE 2007). The contraction rate is usually assessed by counting the number of contractions in 10 minutes, over a 20-minute period. Evidence of 5 contractions or more in 10 minutes is evidence of tachy-systole in spontaneous labour, or hyper stimulation in induced labour (Chapter 19). An excessive number of contractions can result in fetal compromise as a result of prolonged cord compression or reduction in placental perfusion with consequent reduction in blood supply to the fetus.

50. Vaginal examination Although vaginal examinations (VE) have become a routine procedure in labour there is very lifle evidence to support their efficacy. Dixon and Foureur (2010) state that vaginal examinations are arguably considered to be both an intervention and an essential clinical assessment tool in labour. Midwives should remember that to women who have survived sexual abuse, experienced female genital mutilation (FGM), or are extremely anxious, a vaginal examination can be very distressing and sometimes impossible. examinations are undertaken using aseptic principles. Ideally the same person should perform the vaginal examinations to be in a better position to judge any changes. Observations and findings as detailed in Box 16.1 should be noted and recorded accordingly by the midwife.