Assisted vaginal delivery and shoulder dystocia

Chapter 16 Assisted vaginal delivery and shoulder dystocia







FORCES OPERATING IN THE SECOND STAGE OF LABOUR


Successful outcome for assisted delivery is governed by a dynamic balance between the passage, passenger and powers.





ASSISTED DELIVERY


Assistance should be in synchrony with expulsive forces to overcome soft tissue resistance in the second stage of labour, usually for delivery of the fetal head. Resistance arises from individual difference in pelvic musculo-fascial soft tissue, perineal tissue compliance and to some degree moulding of the fetal head.




Instruments for assisted delivery



Forceps








Choosing between forceps and vacuum extraction for assisted deliveries


Contemporary reviews found that vacuum extraction was associated with significantly less maternal trauma than forceps delivery. Fewer caesarean sections were carried out in vacuum extractor groups. However, the vacuum extractor was associated with an increase in neonatal cephalhaematoma and retinal haemorrhages. Forceps were associated with a lower failure rate. The chief disadvantage of forceps is a higher risk of significant maternal perineal injury, especially anal sphincter injuries.


Neither instrument is superior for assisted vaginal deliveries. The forces and requirements for either form of assisted delivery are similar. The choice of instrument depends on the clinical scenario as well as the operator’s experience, training and preferences. Both instruments are equally suited to most assisted deliveries. In circumstances where cephalopelvic disproportion is confidently excluded and speed is of essence (e.g. ominous cardiotocographic tracing), forceps may be the instrument of choice for expediting delivery. The vacuum extractor may be preferred where asynclitism is present, when rotational delivery is needed and there is limited experience with forceps. There is no increased morbidity in completing a delivery by forceps when the vacuum fails provided that the requirements for assisted delivery are fulfilled. Table 16.1 shows a comparison between the two types of instrumental delivery. The long-term outcome is the same for mother and child.


Table 16.1 Instrumental vaginal delivery











































  Forceps Vacuum
Popularity Decreased Increased
Preterm Yes Not before 36 weeks
Undilated cervix (around 9 cm) Contraindicated Yes
Anaesthesia Yes Need less
Failure to achieve delivery Less likely More likely
Tissue trauma Possible Less
Cephalhaematoma Possible More likely
Retinal haemorrhage Possible More likely
Postpartum perineal pain Yes Less


TRACTION PROCEDURES


Box 16.1 describes the types of traction procedure used in assisted delivery.



Mar 16, 2017 | Posted by in NURSING | Comments Off on Assisted vaginal delivery and shoulder dystocia

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