Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01937546 |
| Other study ID # |
SJ-310 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
August 30, 2013 |
| Last updated |
July 23, 2015 |
| Start date |
January 2013 |
| Est. completion date |
July 2015 |
Study information
| Verified date |
July 2015 |
| Source |
Holbaek Sygehus |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
Denmark: The Danish National Committee on Biomedical Research Ethics |
| Study type |
Interventional
|
Clinical Trial Summary
It is unknown if primary delivery of the anterior or the posterior shoulder causes less
perineal tear. The objective of this trial is to evaluate the incidence and degree of
perineal trauma after primary delivery of the anterior shoulder compared to primary delivery
of the posterior shoulder during vaginal birth in primiparous women in a randomized
controlled trial. The hypothesis is that primary delivery of the posterior shoulder reduces
the rate and degree of perineal trauma.
Description:
Background Approximately 85% of vaginal deliveries are accompanied by trauma to the genital
tract, with a higher risk at the first compared to subsequent vaginal births [1,2]. Among
primipara with vaginal deliveries, 86% sustain a vaginal or perineal tear, and 77% require
suturing of a lesion [1,3].
Birth trauma is associated with both short- and long-term morbidity, including pain,
discomfort, dyspareunia, and fecal incontinence, and perineal trauma may cause social
problems and affect the psychological well-being of the mother [1,4]. The level of
postpartum morbidity is related to the degree of trauma [5,6], and studies of preventive
measures are therefore of interest.
Genital tract traumas are classified into subtypes according to the location and severity of
the lesion. Most studies have evaluated the risk factors for 3rd- and 4th-degree perineal
tears that include the anal sphincter complex, the so-called obstetric anal sphincter
injuries (OASIS). Predisposing factors are increasing maternal age, heavier birthweight,
longer duration of the second stage of labour, oxytocin augmentation, occiput posterior
position, and instrumental delivery [7-9]. The risk increases with the number of different
risk factors [9]. Protective factors are previous vaginal delivery, epidural analgesia, and
multiparity [7-9]. Several perineal management techniques used during delivery have been
studied, and a recent Cochrane review concluded that warm compresses and perineal massage
seem to reduce the risk of OASIS [4]. The introduction of an interventional perineal
protection programme also seems to reduce the incidence of OASIS [10-12].
Leading textbooks recommend primary delivery of the anterior shoulder by gentle traction if
the shoulders are not delivered spontaneously [13,14]. However, if shoulder dystocia occurs,
the recommended manoeuvres are primary delivery of the posterior arm or primary delivery of
the posterior shoulder, with the woman positioned on her hands and knees (Gaskin's
manoeuvre) [15,16]. A computer-simulated trial of the manoeuvres used during shoulder
dystocia found that primary delivery of the posterior arm caused an 80% reduction in the
delivery force and a 70% reduction in stretch to the brachial plexus [17]. Primary delivery
of the posterior shoulder could therefore be of advantage during uncomplicated deliveries,
but, to the knowledge of the authors, various methods of shoulder delivery have never been
studied previously.
The objective of this trial is to evaluate the incidence and degree of perineal trauma after
primary delivery of the anterior shoulder compared to primary delivery of the posterior
shoulder during vaginal birth in primiparous women in a randomized controlled trial. The
hypothesis is that primary delivery of the posterior shoulder reduces the rate and degree of
perineal trauma.
Interventions The trial interventions take place during vaginal birth after the delivery of
the head. The head is supported in the spontaneous rotation that occurs after its delivery,
and the shoulders are delivered according to randomization. The intervention is either
primary delivery of the anterior or the posterior shoulder as illustrated in the additional
movie files (see additional files 1 and 2). It is performed by the midwife placing her hands
around the head of the baby and applying gentle traction in the appropriate direction.
All midwives are trained in the two interventions by the primary investigator (HW) to secure
uniform use of the techniques. Training sessions include an introductory video of the two
methods and practical training on a birthing phantom (MODEL-med Sophie and her Mum Full
Birth Obstetric Trainer, Carnegie, Australia). All midwives are also trained in evaluation
and classification of perineal tears using an e-learning programme (GynZone ApS, Aarhus,
Denmark). Primary training sessions (n = 14) took place from February to November 2013, and
additional sessions are held every second month during the course of the trial to train new
midwives and update previously trained midwives. Attendance at a training session accredits
midwifes to deliver included patients.
The participants can deliver in the position they prefer, and if spontaneous delivery of the
shoulders occurs, this is to be respected regardless of randomization. If during delivery
the midwife judges that an alternative method of delivery is preferred with regard to the
safety of the birthing mother, this overrules randomization. Episiotomy may be used in
accordance to local guidelines as judged necessary by the midwife. In case of
vacuum-assisted delivery, which according to guidelines is performed by physicians, the
midwife delivers the shoulders. Any deviations from the protocol are registered on the
clinical registration form.
Assessment After delivery of the placenta, a blinded midwife or doctor not otherwise
involved in the delivery assesses the perineum and grades the perineal tears. Tears are
sutured and officially classified and coded independently of the trial by the midwife
responsible for the delivery or a doctor according to the hospital guidelines. Secondary
outcomes are registered by the midwife responsible for the delivery.
Assessors of the primary outcome and the primary investigator are blinded to randomization.
Registered 3rd and 4th degree tears are validated through manual assessment of patient
records. We assume that especially higher degree tears may be diagnosed after trial
assessment during repair. In order not to underestimate the level of higher degree tears,
data on all 3rd and 4th degree tears in our study population registered in the hospital
register during the trial period will be retrieved after the end of the trial. These data
will be validated against patient records and any additional confirmed cases of 3rd and 4th
degree tears in our study population will be incorporated into the final dataset.
Discussion The purpose of this randomized controlled trial is to compare two methods of
delivering the shoulders during vaginal delivery, with perineal trauma as the primary
outcome.
The literature on delivery techniques is limited, and previous studies have primarily
focused on their effect on OASIS. Most studies have been non-randomized, and different
shoulder delivery techniques have not been evaluated previously. Thus, the strengths of this
study are the randomized design, the intervention studied, i.e. the delivery of the
shoulders at vaginal delivery, and the outcome of any perineal trauma.
The validity of this trial could be affected by the fact that several midwives perform the
interventions. But numerous birth assistants are the reality at most centres, thereby
increasing the external validity and generalizability of the trial. Additionally, it might
be interpreted as a limitation that this is a single-centre trial, although it increases
internal validity of the trial. tThe perineal tears are evaluated by several objective
assessors (midwives or doctors), which possibly might affect the validity of the outcome
assessment. We will try to overcome this issue by validating the registered higher degree
tears (3rd and 4th degree) by examining the patient records. Additionally, we are planning
to retrieve data on all 3rd and 4th degree tears in our study population during the study
period from the hospital registers and validate this data against patient records. We assume
that especially higher degree tears may be diagnosed after trial assessment. These tears
will be registered centrally because registration commonly takes place after lesion repair.
Thus, all higher degree tears included in our final analysis will be validated.
Most delivery assistance techniques used today are based on tradition and heritage and are
not evidence based. This trial provides an example of how vaginal delivery techniques may be
evaluated in a randomized controlled trial.
The results of this trial will clarify the role delivery of the shoulders has on perineal
trauma and thereby add knowledge about recommended birthing techniques.
For futher details please see the published protocol:
Willer H, Aabakke AJ, Krebs L. The effect of primary delivery of the anterior compared with
the posterior shoulder on perineal trauma: a study protocol for a randomized controlled
trial. Trials 2014;15:291.
