Oxford Handbook of Midwifery (68 page)

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Normal labour: third stage
‌‌

Chapter 15

287

Care during the third stage of labour
288
Physiological management of the third stage
290
Active management of the third stage
292
Assessing and repairing the perineum
294
Examining the placenta and membranes
298

CHAPTER 15
Normal labour: third stage

288‌‌

Care during the third stage of labour

The third stage of labour is potentially hazardous for the woman due to the increased risk of haemorrhage, particularly immediately following delivery of the placenta. Life-threatening haemorrhage occurs in approxi- mately 1 per 1000 births. However, estimates of PPH vary widely—from 4% to 18%.
¹

Definition of primary postpartum haemorrhage

Primary PPH is traditionally defined as the loss of >500mL of blood from the genital tract within the first 24h after the birth. If haemodynamic changes manifest in the newly delivered woman with loss <500mL, this may also be regarded as a primary PPH. Recently a blood loss of 1000mL has been considered as a more realistic definition of primary PPH.

Causes and risk factors associated with primary PPH

History

• Previous PPH or previous retained placenta
  
• Previous precipitate, prolonged, or traumatic labour
  
• Previous APH
  
• Uterine scar
  
• HIV/AIDS
  
• Uterine fibroids or other anomalies.
  

  Pregnancy
  

• High parity
  
• Multiple pregnancy
  
• Polyhydramnios
  
• Coagulation disorders
  
• Anaemia
  
• Placenta praevia
  
• APH
  
• Pre-eclampsia.
  

  Labour
  

• Precipitate labour
  
• Prolonged labour
  
• Induction of labour or augmentation of labour
  
• Large doses of narcotics and/or epidural analgesia
  
• General anaesthesia
  
• Tocolytic drugs (used to suppress uterine activity in preterm labour)
  
• Infection—chorioamnionitis
  
• Ketoacidosis.
  

  Third stage
  

  •
  Incomplete separation of the placenta
  

• Full bladder
  
• Retained cotyledon, placental tissue, or membranes
  
• Mismanagement of the third stage, disrupting the rhythm of myometrial activity
  
• Inversion of the uterus.
  

  CARE DURING THE THIRD STAGE OF LABOUR
  

  289
  

  There are two ways in which the third stage may be managed: either by active management (b see Active management of the third stage,
  

  1. 292) or by physiological management (b see Physiological manage- ment of the third stage, p. 290). However, it has been suggested that the third stage should not be managed at all, and that attention to creating the right environment to enhance physiological efficiency is far more important; therefore preventing intervention that is likely to lead to complications.
     ²
     

     General care
     

with a blood loss of up to 1000mL.
³
However, accurate estimation of blood loss is crucial for both active and physiological management.

1. Harrison K (1998). Management of postpartum haemorrhage.
   Prescriber Update
   16
   , 4–9.
   
2. Odent M (1998). Don’t manage the third stage of labour!
   Practising Midwife
   1
   (9), 31–3.
   
3. Bose P, Regan F, Paterson-Brown S (2006). Improving the accuracy of estimated blood loss at obstetric haemorrhage using clinical reconstructions.
   BJOG International Journal of Obstetrics and Gynaecology
   113
   , 919–24.
   

   CHAPTER 15
   Normal labour: third stage
   

   290‌‌
   

   Physiological management of the third stage
   

   A physiological third stage of labour may be the choice for women who prefer to avoid intervention during childbirth. Placental separation occurs physiologically without resorting to oxytocic drugs, and expulsion of the pla- centa is achieved by maternal effort The average length of the third stage is 15–60min, although in some cases, provided there are no abnormal signs, it may occasionally last up to 120min. The Bristol trial indicated that there is a higher incidence of PPH with a physiological third stage.
   ¹
   However, criticisms of the trial suggest that inexperience in managing the third stage of labour was a serious flaw. More recent studies have found no difference in the incidence of PPH between active and physiological management of the third stage.
   

   Physiology of the third stage
   

   • Detachment of the placenta commences with contractions that deliver the baby’s trunk.
     
   • Once the baby is born, the uterus is greatly reduced in size due to the powerful contraction and retraction of the uterine muscles.
     
   • Consequently, the placental site is also greatly reduced. When the placental site is reduced by one-half it becomes puckered and starts to peel away from the uterine wall.
     
   • This is assisted by the tightly compressed and contracted uterus. As a result, fetal blood is pumped into the baby’s circulation. Maternal blood is driven back into the spongy layer of the decidua.
     
   • The congested veins are then forced to rupture. The effused blood from the congested veins results in detachment of the placenta. The veins are caused to rupture as the blood in these veins cannot return to the maternal circulation.
     
   • Bleeding is controlled by the presence of ‘living ligatures’. Plain muscle fibres of the uterus entangle around the exposed bleeding blood vessel site, preventing further blood loss.
     
   • When separation of the placenta is complete (usually 3–5min), the upper segment of the uterus contracts strongly, forcing the placenta into the lower segment and then the vagina.
     
   • Detachment of the membranes commences in the first stage of labour, when the membranes rupture they are shorn from the internal os. This is then completed in the third stage when the weight of the descending placenta allows them to peel away from the wall of the uterus.
     

Methods of detachment

Schultze method
: approximately 80% of cases detach by this method. The placenta starts to detach from the centre and leads its descent down the

vagina. The fetal surface of the placenta therefore appears first at the vulva,

with the membranes trailing behind. The retroplacental clot is situated inside the membrane sac. Minimal visible blood loss is the result.

Matthews Duncan method
: separation of the placenta commences at the lower edge, which allows the placenta to slide down sideways, exposing the maternal surface. This usually results in increased bleeding due to the slower rate of separation and no retroplacental clot being formed.

PHYSIOLOGICAL MANAGEMENT OF THE THIRD STAGE

291

Expectant or physiological management of the third stage

It is important that midwives familiarize themselves with the principles and practice of the physiological third stage (as opposed to active manage- ment, with which they may have more experience). It is equally impor- tant to ensure that consent from the woman has been obtained, and that she understands her role. A physiological third stage is not recommended when the preceding stages have not been conducted physiologically.

Management