Slow Labour Progress Clinical Trial
Slow labour progress is common in nulliparous women and is associated with childbirth
complications and negative birth experiences. Oxytocin augmentation is widely used to treat
slow labour despite associated risks for the fetus. An ongoing debate concerns whether
oxytocin should be administered directly or postponed after arrested labour. The overall aim
is to study labour progress in healthy nulliparous women and to compare childbirth outcomes
and experiences in women randomised to expectant versus early oxytocin augmentation for slow
labour progress.
The hypothesis is that it is to early to start oxytocin treatment when labour progress has
been slow for 2 to 3 hours in healthy women having their first baby and therefore beneficial
for childbirth outcomes to postpone oxytocin for another 3 hours. In this randomised
controlled trial nulliparous women with a normal pregnancy, spontaneous onset of active
labor at term, and a cervical dilatation of 4 - 9 centimetres on admission to the delivery
ward were included (n=2,072). All women whose labour did not progress after amniotomy
(n=630) were randomly allocated either to labour augmentation by oxytocin infusion (Early
oxytocin, n=314) or to postponement of oxytocin augmentation for another three hours
(Expectant, n=316). One month postpartum the women received a postal questionnaire
concerning their experiences of labour and birth. All participating women gave their
informed consent. Maternal and neonatal outcomes like mode of delivery, postpartum
haemorrhage, perinatal lacerations, low Apgar score, need of neonatal intensive care and
maternal experiences of childbirth were compared between the randomised groups.
In contemporary handling of labouring women in the western world, it has become extremely
common to intervene through "active" or disciplined" management (Enkin et al., Widela et
al., Gerdhardstein et al., Frigoletto et al). It is a widespread routine - and potential
side effects will therefore have a great impact. The use of the hormone oxytocin to enhance
and speed up labour is the most common method, but the sparse scientific data regarding its
effect are inconsistent and mostly demonstrate uncertain and sometime side effects (Thornton
& Lilford, Frazer 1994, 1998, Cammu & Van Eeckhout).
The effects, when evaluated, are short-term effects of maternal (obstetric) and fetal
outcomes. The studies performed have mostly aimed to investigate whether the active
management can reduce the rate of caesarean sections. However, in a meta-analysis of four
randomised studies of the effects of oxytocin as intervention in spontaneous labour
(Frazer), no significant reduction in the incidence of caesarean section, instrumental
deliveries, and use of analgetics or hyper stimulation of labour was found. The only
statically significant differences were in side effects: an increased incidence of
discomfort and of pain in the group given oxytocin. In this meta-analysis, no significant
differences in fetal conditions between the groups were found.
Only one of the studies found sought the women's view on the augmentation procedures
(Enkin). Over half of the women who were interviewed, said that the oxytocin treatment was
unpleasant and indicate that they would like to try without the drug when giving birth the
next time. Over 80% felt that it had increased the amount of pain that they had experienced.
In spite of poor evidence of benefits, around half of birth giving women in Sweden receive
oxytocin during labour and in some other countries, far more than that (Waldenström,
O'Driscoll, Enkin). It has become the standard care of treating labours with slow progress.
According to an investigation by the Swedish National Board of Health and Welfare
(Socialstyrelsen 1996), the indications for oxytocin use and the amounts administered are
not systematically recorded, and the assessments of its effects are even less well recorded.
This makes evaluation by using existing documents very unreliable, and randomised controlled
studies.
Aims of the study
The aims of the study are:
- To study the effects of oxytocin treatment vs no or delayed oxytocin treatment on the
obstetrical and fetal outcome of spontaneous, but prolonged labour. Primary outcome is
rate of spontaneous vaginal deliveries. Secondary outcome are length of labour,
postpartum haemorrhage, sphincter lacerations, Apgar score, perceived pain and sense of
safety.
- To study labour experiences in women exposed to oxytocin treatment vs women without
oxytocin treatment.
Methods
The planned study design is a randomised controlled study with healthy women with normal
pregnancies and spontaneous labour, where labour progression is deemed to be prolonged.
Inclusion criteria
Healthy women with full-term, normal pregnancies, spontaneous onset of active labour
(effaced cervix and minimum 4 cm dilated) and about to give birth to their first child.
Exclusion criteria
Women with multiple pregnancies, complicated pregnancies, maternal disease during
pregnancies, ruptured membranes for more than 2 hours before onset of labour contractions,
and fetus in breech presentation.
Sample size calculation
A sample size of 247 in each group is needed to show a difference in spontaneous vaginal
deliveries from 81,2% to 90% with a 2-sided test, alpha=0,05 and 80% power.
Procedure
Women fulfilling the criteria as described above are regarded as potential study subjects.
Information about the study is distributed during the last trimester at the antenatal
clinic. On arrival at the delivery ward, all women fulfilling these criteria are again
informed about the study and asked for consent to participate. The progression of labour is
thoroughly followed and documented for women who have agreed to participate. If the labour
is prolonged during the active phase and is classified as inertia, i.e. with no further
opening of the cervix for 2 hours or less than 1 cm in 3 hours, the subject are randomly
allocated to either labour augmentation by means of oxytocin infusion within twenty minutes
(standard care) or to expectancy and observation another 3 hours (experimental group) If the
subjects in the experimental group after the 3 hours still do not progress in their labour,
a reassessment regarding the need for labour augmentation is done. Women fulfilling
inclusion criteria, and who have agreed to participate, but whose labours proceed normally,
are followed according the same protocol, hence serving as external controls.
Assessment and follow-up
The handling of the participants will be done according to a standard protocol holding
continuous documentation of the progression of labour, of the amount of oxytocin
administered, of the analgesia used and of the obstetric outcome (caesarean section,
instrumental vaginal delivery, length of labour, Apgar score etc). At the inclusion in the
study, the women assess their expectancies, their perceived pain and sense of safety, using
a visual analogue scale. Pain and sense of safety is then assessed at several occasions
during and after delivery.
In order to study the women's retrospective perceptions of their labour, they receive a
questionnaire regarding their perceived experience one month post partum. This instrument
focus on perceived pain, perceived safety, perceived participation in decision-making, sense
of control and patient satisfaction. This questionnaire also contains questions regarding
breast-feeding and a separate part is to be answered by the father. The latter part holding
questions about the fathers' levels of preparation for the delivery, and his expectations
and experiences as a supportive person in the labour room. A subgroup of the subjects (24 +
24) - oxytocin exposed and unexposed women - will be interviewed at one and four months
after birth, using a qualitative interview method.
Assessment of the baby is done at birth through Apgar scoring, fetal pH and base excess from
the umbilical cord blood. In addition to this, a subgroup of the neonates will get their
motor activity, heart frequency and respiration activity continuously registered during the
first night after birth. This is done with the help of a so-called "sleep-box"
Safety
Three hours after the inclusion in the study, a reassessment of the progress of the labour
is performed to evaluate whether the progression is satisfactory, or if oxytocin for those
assigned to the experimental group is assessed to be required (procedures).
Reassessments are then done regularly with 2-3 hours interval.
Ethics
Making a randomised, clinical study with care/treatment group and non-care/non-treatment
group, always raises the question whether it is good ethics or not to abstain from the
presently applied care programme. In this case, scientific data regarding the beneficial
outcomes are ambiguous and inconsistent, and it is thus not obvious which of the procedures
offered is "best" for the woman and the child. With this background, performing the study
including well informed subjects and aiming at evaluating effects of standard procedures,
must be considered ethically acceptable.
Importance of the study
There are few controlled studies on the effects of the standard procedure of treating slow
labour progression with oxytocin and these show conflicting results. Considering this
widespread treatment involving large population of women and newborns, it is of great
importance to evaluate potential benefits and side effects in controlled studies. Knowledge
about this is especially important in the reorganisation and rationing of resources within
obstetric services. In the attempts to shorten women's hospital stays, the shortening of
duration of labour has sometimes been considered a means to make obstetric care more
cost-efficient and this fact makes independent evaluation of the care even more important.
Furthermore, patients have the right to get evidence based care and treatment. This study
will hopefully contribute to a better evidence based handling of women in labour who are
subjected to secondary inertia, and in addition it will give us more information about
fathers' experiences, which will help us enhance the care of the next-to-kin of the
labouring woman.
References
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Allocation: Randomized, Masking: Open Label, Primary Purpose: Treatment