Obstetric Emergencies

Chapter 23 Obstetric Emergencies



Vasa praevia


The term vasa praevia is used when a fetal blood vessel lies over the os, in front of the presenting part. This occurs when fetal vessels from a velamentous insertion of the cord cross the area of the internal os to the placenta. Vasa praevia may sometimes be palpated on vaginal examination when the membranes are still intact. It may also be visualised on ultrasound. If it is suspected, a speculum examination should be made.



Ruptured vasa praevia


When the membranes rupture in a case of vasa praevia, a fetal vessel may also rupture. This leads to exsanguination of the fetus unless birth occurs within minutes.



Diagnosis




image Slight fresh vaginal bleeding, particularly if it commences at the same time as rupture of the membranes.


image Fetal distress disproportionate to blood loss.



Management


See Box 23.1.



Box 23.1 Management of vasa praevia




• Request urgent medical aid


• Monitor the fetal heart rate


• If the mother is in the first stage of labour and the fetus is still alive, an emergency caesarean section is carried out


• If in the second stage of labour, delivery should be expedited and a vaginal birth may be achieved


• A paediatrician should be present at delivery. If the baby is alive, haemoglobin (Hb) estimation will be necessary after resuscitation



Presentation and prolapse of the umbilical cord


See Box 23.2 for definitions.



Box 23.2 Definitions



Cord presentation




• The umbilical cord lies in front of the presenting part, with the fetal membranes still intact



Cord prolapse




• The cord lies in front of the presenting part and the fetal membranes are ruptured



Occult cord prolapse




• The cord lies alongside, but not in front of, the presenting part




Predisposing factors


Any situation where the presenting part is neither well applied to the lower uterine segment nor well down in the pelvis may make it possible for a loop of cord to slip down in front of the presenting part. Such situations include:



image high or ill-fitting presenting part


image high parity


image prematurity


image malpresentation


image multiple pregnancy


image polyhydramnios.



Cord presentation


This is diagnosed on vaginal examination when the cord is felt behind intact membranes. It is, however, rarely detected but may be associated with aberrations in fetal heart monitoring such as decelerations, which occur if the cord becomes compressed.



Management


See Box 23.3.



Box 23.3 Management of cord presentation




• Under no circumstances should the membranes be ruptured


• Summon medical aid


• Assess fetal wellbeing, using continuous electronic fetal monitoring if available


• Help the mother into a position that will reduce the likelihood of cord compression


• Caesarean section is the most likely outcome



Cord prolapse



Diagnosis




image Diagnosis is made when the cord is felt below or beside the presenting part on vaginal examination.


image A loop of cord may be visible at the vulva.


image Whenever there are factors present that predispose to cord prolapse, a vaginal examination should be performed immediately on spontaneous rupture of membranes. Variable decelerations and prolonged decelerations of the fetal heart are associated with cord compression, which may be caused by cord prolapse.



Immediate action and management


See Box 23.4.



Box 23.4 Management of cord prolapse



Immediate action




• Call for urgent assistance


• If an oxytocin infusion is in progress, this should be stopped


• A vaginal examination is performed to assess the degree of cervical dilatation and identify the presenting part and station. If the cord can be felt pulsating, it should be handled as little as possible


• If the cord lies outside the vagina, replace it gently to try to maintain temperature


• Auscultate the fetal heart rate


• Relieve pressure on the cord


• Keep your fingers in the woman’s vagina and, especially during a contraction, hold the presenting part off the umbilical cord


• Help the mother to change position so that her pelvis and buttocks are raised. The knee–chest position causes the fetus to gravitate towards the diaphragm, relieving the compression on the cord


• Alternatively, help the mother to lie on her left side, with a wedge or pillow elevating her hips (exaggerated Sims’ position)


• The foot of the bed may be raised


• These measures need to be maintained until the delivery of the baby, either vaginally or by caesarean section


• Consider inserting 500 ml of warm saline into the bladder to relieve the pressure if transfer to an obstetric unit is required



Treatment




• Delivery must be expedited with the greatest possible speed


• Caesarean section is the treatment of choice if the fetus is still alive and delivery is not imminent, or vaginal birth cannot be indicated


• In the second stage of labour the mother may be able to push and you may perform an episiotomy to expedite the birth


• Where the presentation is cephalic, assisted birth may be achieved through ventouse or forceps



Shoulder dystocia




Definition


The term ‘shoulder dystocia’ is used to describe failure of the shoulders to traverse the pelvis spontaneously after delivery of the head. The anterior shoulder becomes trapped behind or on the symphysis pubis, while the posterior shoulder may be in the hollow of the sacrum or high above the sacral promontory. This is, therefore, a bony dystocia, and traction at this point will further impact the anterior shoulder, impeding attempts at delivery.



Risk factors


These can only give a high index of suspicion:



image post-term pregnancy


image high parity


image maternal obesity (weight over 90 kg)


image fetal macrosomia (birth weight over 4000 g)


image maternal diabetes and gestational diabetes


image prolonged labour (first and second stages)


image operative delivery.



Warning signs and diagnosis


The birth may have been uncomplicated initially, but the head may have advanced slowly and the chin may have had difficulty in sweeping over the perineum. Once the head is born, it may look as if it is trying to return into the vagina.


Shoulder dystocia is diagnosed when manoeuvres normally used by the midwife fail to accomplish birth.



Management


See Box 23.5 and Figs 23.1–23.3.



Box 23.5 Management of shoulder dystocia




• Summon help – an obstetrician, an anaesthetist and a person proficient in neonatal resuscitation


• Attempt to disimpact the shoulders and accomplish delivery. An accurate and detailed record of the type of manoeuvre(s) used, the time taken, the amount of force used and the outcome of each attempted manoeuvre should be made


• Try the procedures for 30–60 seconds; if the baby is not born, move on to the next procedure



Non-invasive procedures




• Change in maternal position


• McRoberts manœuvre. Involves helping the woman to lie flat and to bring her knees up to her chest as far as possible to rotate the angle of the symphysis pubis superiorly and use the weight of her legs to create gentle pressure on her abdomen, releasing the impaction of the anterior shoulder


• Suprapubic pressure (Fig. 23.1). Pressure is exerted on the side of the fetal back and towards the fetal chest to adduct the shoulders and push the anterior shoulder away from the symphysis pubis. Can be used with the McRoberts manoeuvre.

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Related posts:

  1. The Placenta
  2. Prolonged Pregnancy and Disorders of Uterine Action
  3. The Third Stage of Labour
  4. Problems of Pregnancy

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Jul 11, 2016 | Posted by in MIDWIFERY | Comments Off on Obstetric Emergencies

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