Strength and limitations
As far as we are aware of is this
the first study comparing the effect of a hysteroscopic niche resection
with LNG-IUD insertion on the reduction of spotting in women with a
niche in the CS scar. The strength of our study is that we evaluated
symptoms and side effects in a prospective and structured way using
menstrual diaries. We had a homogeneous population due to the clear
inclusion and exclusion criteria. Consecutive inclusion of patients,
structured follow-up at four fixed evaluation points and the very low
drop-out rate in both study groups reduce the risk on selection and
verification bias.
However, our study has also some limitations. First, this study was
divided into groups based on shared-medical decisions making this
increases the risk on selection bias in comparison to a randomized
design. This is underlined by the differences in age and in TRM between
the two groups. Although additional analyses have shown that these
variables were not related to the primary outcome. Due to the small
sample size we were not able to study the effect of other potential
confounders. Future randomized controlled studies of sufficient sample
size should be carried out in the future to confirm our data.