Strengths and Limitations
The strengths of this study are that it was conducted to international
standards with UK sponsor oversight and regular monitoring visits to
ensure compliance. The presence of a one researcher, allocated to each
recruited woman throughout her induction and labour ensured that the
data was fully collected and that hyperstimulation, a factor that is
often poorly recorded, could be accurately assessed every 30 minutes
throughout the labour. Although this process lessened the study’s
external validity, it ensured that the study had complete follow-up and
no missing data, despite being conducted in busy delivery units. The
inclusion of two teaching hospitals in an urban and rural setting, and a
district hospital allowed us to assess the effect of the intervention
across three different types of delivery settings. A detailed comparison
of the trial data between the study sites will be published elsewhere.
It is very difficult to blind a study in which a titrated infusion is
compared with an oral tablet, and an open label study is prone to
clinician and researcher bias. Furthermore, the use of a placebo
infusion would have nullified any mobility effect of the use of LDOM for
ongoing induction after membrane rupture. Nevertheless, bias is
particularly a risk in this study where some clinicians reported being
anxious about the risks of LDOM in labour and being reluctant to give
over 3 doses. This could have led to an excess of CS in the LDOM group
after 6 hours, but this was not seen in the survival curves (Figure 4).