The influence of the 3 ‘Ps’

1. The influence of the 3 ‘Ps’ • Dystocia can be as a result of : • ine-ective uterine contractions • , malposition of the fetus • a relative or absolute CPD • , malpresentation, • combination of these. These may result in poor progress during the active phase or a cessation of cervical dilatation following a period of normal dilatation • An understanding of the role played by the 3 ‘Ps’ – passages, passenger and powers – will help in determining why there is a delay in progress in first or second stage of labour and what action might be taken.

2. the majority of women have grown up well nourished, healthy, excluding possible trauma to the pelvis. -the impact of a full rectum, full bladder and fifibroids cannot be ignored in causing a delay in the progress of labour. Amalpresentation such as shoulder, brow or face (mento-posterior) is one of the causes of poor progress or prolonged labour and this may occur as a result of a problem with the passage

3. A brow refer to (mento-anterior) • the face in mento-posterior position may rotate to mento-anterior at the pelvic flfloor and if so a vaginal birth may be possible • The shoulder, brow or face (mento-posterior) cannot be born vaginally but a carefully executed abdominal and vaginal examination will exclude or confirm this so that the necessary action can be taken to prepare the woman for caesarean section.

4. When the fetus is adopting an attitude where the head is deflflexed or slightly extended and the occiput is posterior the presenting diameters are larger and there will be a degree of ascynclitism. This inevitably slows progress but does not necessarily mean progress is abnormal. This might be considered a relative CPD because with ff effective uterine contractions the fetus may adopt a more flflexed attitude. On some occasions more time is needed to do this safely.

5. rupturing the membranes when the fetus is an occipitoposterior position may result in a sudden descent of the fetal skull resulting in a deep transverse arrest whereby the occipitofrontal diameter (11.5 cm) is caught on the bi-spinous diameter of the outlet (10–11 cm). • Epidural anaesthesia has been found to delay the progress of labour in the first and second stage so where there is an occipitoposterior position ,The musculature of the pelvic flfloor plays an important part in assisting the rotation of the presenting part and epidural anaesthesia causes the pelvic flfloor to relax inhibiting rotation. It also has an impact on the stretching of the birth canal that normally triggers the neuro-hormonal reflex (Ferguson's reflflex). In some cases the head is simply (normally)

6. large and any decision to intervene at this point with oxytocin may increase strength and frequency of uterine contractions. • Although the uterus has prepared itself for the metabolic activity of labour, as labour continues the smooth muscle uses up its metabolic reserves and becomes tired. Any change to the strength, length or frequency of contractions will affffect progress and is indicative of ineffcient uterine action.

7. Whilst some ketosis is considered normal in labour there remains a need for additional supplies of energy if the uterus is to continue contracting effectively and enable labour to progress without the need for medical intervention • Women need to have adequate oral intake in order to cope with the very real demands that labour puts on their body.

8. The midwife's role in caring for a woman in prolonged labour • A prolonged labour leads to increased levels of stress, anxiety, fear and fatigue, and increases the risk of infection, PPH and emergency caesarean section ,The importance of effective antenatal education in developing a plan of care for labour should not be underestimated. Advice on suitable food and drink to eat in the early stages of labour to maintain energy levels, positions and activities to encourage a forward rotation where there is an occipitoposterior position are just some of the ways that might help to assist the woman in the normal progress of labour.

9. When the woman and her partner come into hospital, continuity of caregiver helps to create a sense of trust between the woman, partner and midwife but also allows for more accurate assessment over time to enable the midwife to suggest non-interventionist ways in which progress can be maintained if appropriate. An alternative position might help to facilitate more effective contractions or improve pelvic diameters when the position of the baby is posterior.

10. At this stage it is also important to maintain hydration, to encourage voiding and to suggest non-pharmacological ways to relieve pain. Facilitating autonomy by keeping the woman and her partner informed of her progress and the choices she has is important in helping her to feel in control and to alleviate anxiety. Raised adrenalin levels as a result of fear, anxiety or pain can impact negatively on uterine activity and can slow progress in labour.

11. Accurate observations in labour are critical in assessing progress. Recognition and detection of abnormal progress in labour with appropriate clinical response will improve the outcome of labour for both mother and baby • An abdominal examination undertaken can provide vital information about the labour with regard to the lie, presentation, position and descent of presenting part as well as the length, strength and frequency of contractions whereby any change in the pattern of the contractions can be picked up.

12. If the woman consents to VE the findings can be compared to provide a more comprehensive picture of the progress of labour. On VE the midwife is assessing the presence and degree of moulding of the fetal skull, the presence and position of caput in relation to sutures and fontanelles, and the dilatation of the cervix noting any thickening and its application to the presenting part. Any changes to the colour of the liquor if the membranes have previously ruptured, or to the fetal heart rate will give some indication as to how the fetus is coping with the progress of labour. Continuity of caregiver at this time reduces the likelihood of interobserver variations whilst increasing the chance of spontaneous vaginal birth

13. When the decision to augment labour has been agreed by all parties, the woman and her partner will need additional support from the midwife, as the interventions necessary for this process may be very different from the birth they had previously imagined. Psychological as well as physical support is important at this time, as the control of the birth of their baby now appears to be in the hands of a third party and this can lead to negative feelings of the childbirth experience.

14. The management of prolonged labour is a collaborative ffeffort involving the woman and her partner, the midwife, obstetrician and anaesthetist. The normal pattern of observations and care in labour apply and any deviations from normal are reported to the obstetrician. When an ARM has been performed to augment labour an appropriate period of grace should be given for ffeffective uterine contractions to resume before commencing an oxytocin infusion. The uterus responds with increased sensitivity to the oxytocin infused as the cervix dilates and it may be necessary to

15. reduce the rate of the infusion as full dilatation is approached to avoid hyperstimulation of the uterus and the effects on mother and fetus. With the woman's consent, an assessment will • be made 2–4 hours after ARM or after commencing oxytocin to ascertain the likelihood of a successful vaginal birth. If there is persistent poor progress in the active phase despite optimal contractions, 4 to 5 per 10 minutes lasting more than 40 seconds, and the woman is pain-free, well hydrated and with an empty bladder, it is unlikely that continuing with an oxytocin infusion will lead to a vaginal birth.

16. The decision to augment labour in parous women or in women with prior caesarean section must be made by an experienced obstetrician because of the very real risk of hyperstimulation and uterine rupture.

17. Delay in the second stage of labour • The second stage of labour can be divided into a passive (pelvic) phase and active (perineal) phase • Delay in this stage of labour may be due to ; • ;malposition causing failure of the vertex to descend and rotate • ineffective contractions due to a prolonged fifirst stage • large fetus and large vertex • absence of the desire to push with epidural analgesia. • *Assuming the woman is receiving active support and encouragement during the second stage, and has trust in those caring for her, some of these situations a change of position and further encouragement, or the judicious use of an oxytocin infusion to avoid the need for an instrumental or operative birth.

18. Time limits in second stage range from 30 minutes to 2 hours for parous women and 1 to 3 hours for nulliparous women ,but an understanding of the different phases as the head negotiates the birth canal can avoid the encouragement of premature bearing down efforts, which only serve to tire and demoralize the mother. • The variation in time limits takes into consideration the impact of epidural analgesia on the desire to push in the second stage. The active phase when the mother is bearing down is the most critical time.

19. When a diagnosis of delay in the second stage has been made the case is referred to the obstetrician for review and assessment. • The impact on both mother and fetus if the second stage is allowed to exceed a pre-determined time limit must be weighed against the risks of any interventions at this critical time in the childbirth experiences.

20. Obstructed labour • Whilst obstructed labour is common in developing countries ,woman has laboured unattended at home for several hours and then seeks help at a hospital. • Obstructed labour occurs when despite good uterine contractions there is no advance of the presenting part. Possible causes of obstructed labour include absolute CPD, deep transverse arrest, malpresentation, lower segment fibroids, fetal hydrocephaly and multiple pregnancy with conjoined or locked twins. Because of the high presenting part

21. if the woman goes into labour there may be spontaneous rupture of the membranes and cord prolapse with related risk to the fetus. If the condition is not recognized the mother's uterus will continue to contract to overcome the obstruction. She will become progressively more dehydrated, ketotic, pyrexial and tachycardic. The fetus will develop a bradycardia because of the ineffective contractions. As the uterus continues to contract and retract the upper segment becomes progressively thicker, closely enveloping the fetus, and the lower segment becomes increasingly thinner.

22. In nulliparous women the contractions may cease for a period before resuming again with increasing strength and frequency with little interval between contractions until the uterus assumes a state of tonic contraction. The difference between upper and lower segment may be seen as a ridge obliquely crossing the abdomen (Bandl's ring). The mother is in severe and unrelenting pain. If VE is possible the presenting part will be high with excessive moulding • The uterus is in imminent danger of rupture and emergency measures must be taken

23. if the situation has been allowed to get this far. Uterine rupture leads to maternal mortality and the tonic contractions and uterine rupture cause the hypoxia, asphyxia and subsequent perinatal mortality • If the woman has been discovered in this condition at home a paramedic ambulance should be called for immediate transfer to hospital. The labour suite should be informed, which, in turn, should contact the senior obstetrician, anaesthetist, paediatrician, theatre and special care unit.

24. Whilst waiting for the ambulance the midwife should cannulate, take blood for urgent cross-match and site an intravenous infusion. The woman's General Practitioner (GP) can be called if close by to provide additional help and support until the ambulance arrives. Observations of mother and fetus, and any actions taken and by whom, are recorded in the maternity notes as soon as possible. If obstructed labour is diagnosed on admission to hospital an emergency caesarean section is performed

26. obstructed labour is not something that is managed, in that when a woman is receiving skilled antenatal and intrapartum care it is not something that should occur. During antenatal care the midwife will highlight any predisposing maternal or fetal factors that might impact on normal progress in labour with appropriate referral to the obstetrician so that a full and frank discussion can take place and a decision made with the woman on the safest mode of birth. During labour, skilled observation and assessment of progress, particularly skilled abdominal examination, will alert the midwife to any malpresentation or failure of the presenting part to advance despite optimal uterine contractions.

27. VE will ficonfirm suspected malpresentation, and where the presentation is vertex, reveal increasing caput or moulding. With a high presenting part in labour cervical dilatation will be extremely slow and there will be little if any application to the presenting part. The obstetrician is informed as soon as possible so that the birth can be expedited. As for all women, despite the very real threat to maternal and perinatal wellbeing these procedures should only be undertaken with maternal consent.

28. Precipitate labour • Precipitate labour is defined as ‘expulsion of the fetus within 3 hours of commencement of contractions’ • In some women the uterus is over-effcient and much or all of the first stage is not recognized because contractions are not painful and the realization of the birth of the head may be the fifirst indication that labour has actually started. In women with spontaneous onset of labour the incidence of precipitate labour is approximately 2%, and women having a precipitate labour are at risk of placental abruption.

29. Other problems that may be associated with a precipitate labour include soft tissue trauma of the maternal genital tract due to sudden stretching and distension as the baby is born • fetal hypoxia as a result of the frequency and strength of the contractions • intracranial haemorrhage from the sudden compression and decompression of the fetal skull as it passes through the birth canal with speed, and possible injury as the head and body emerge rapidly and fall to the flfloor.

30. The unexpected nature of the event means that the place of birth may be inappropriate and the baby may be further compromised if the importance of maintaining the baby's temperature is not recognized. The overeffcient uterus may relax after the birth of the baby, resulting in retained placenta and/or PPH. The psychological impact of such a rapid birth must not be underestimated, and not surprisingly some women will be in a state of shock after the event.

31. Whilst precipitate labour will often recur in subsequent pregnancies there is no evidence to recommend IOL as a preventative measure. However, a woman who has experienced an unattended precipitate labour and birth may request IOL in order to ensure an attended birth in a safe environment

32. Making birth a positive experience For the woman who has a spontaneous onset of labour at term, has a single fetus in a cephalic presentation and who has no underlying medical disorders, labour should be about the normal physiological event. The only intervention it requires on the part of the midwife is to be there to meet the needs of the woman and to offer continuous support and encouragement to enable her to feel secure and confident in those caring for her at this momentous time.

33. The views of midwives and doctors on childbirth are often outcome is the safety of the mother and baby. Whilst a high-risk pregnancy and labour cannot be made low-risk it can still be a positive birthing experience for the woman and her partner. Childbearing is a time of major life transition and each woman and partner deserve to have a positive birth experience whether labour is spontaneous or induced and the birth is vaginal or by caesarean section. Working together as a team cannot but help to contribute to that positive birth experience.