tailieunhanh - Ebook Best practice in labour and delivery (2/E): Part 2

Part 2 book “Best practice in labour and delivery” has contents: Management of the third stage of labour, postpartum haemorrhage, management of morbidly adherent placenta, episiotomy and obstetric perineal trauma, labour in women with medical disorders, and other contents. | Chapter 14 Management of the Third Stage of Labour Hajeb Kamali and Pina Amin The third stage of labour is defined as the time from the birth of the baby to the delivery of the placenta and membranes. In the majority of cases, the third stage is uneventful. However, complications of the third stage lead to significant mortality and morbidity, especially so in the developing nations. Worldwide, postpartum haemorrhage leads to approximately 130 000 deaths annually, accounting for of all births [1]. It is the leading cause of maternal death in Africa and Asia, accounting for up to half of these [2]. The death rate in the UK from postpartum haemorrhage (PPH) had not significantly changed in the last Confidential Enquiry into maternal death [3], at per 100 000. However, this still places obstetric haemorrhage as the third highest cause of direct maternal death. In total, it accounted for 17 maternal deaths in the UK during the period of 2009–12 and still accounts for 25% of maternal deaths in the developing world [4]. Physiology of the Third Stage of Labour Placental Separation During birth of the baby, there is a rapid and significant reduction in uterine size. The average of this diminution in length from onset of birth to its completion is inches in 5 min. This is achieved by myometrial retraction, which is a unique characteristic of the uterine muscle, involving all three muscle fibre layers, allowing maintenance of the shortened length following each successive contraction. This continued retraction results in thickening of the myometrium, reduction of uterine volume and shrinkage of placental bed. The non-contractile placenta is undermined, detached and propelled into the lower uterine segment. This process is usually completed within min of delivery of the baby [5]. The second mechanism involved in uterine separation is haematoma formation, which occurs secondary to venous occlusion and vascular rupture in the placental bed caused by .