Strengths and Limitations
To our knowledge, this is the first prospective study with the largest
sample size (n=180) and randomized controlled design, investigating the
effect of systemic oral progestin with or without LNG-IUS on
fertility-preserving outcome in AEH patients. However, it is undeniable
that several limitations in this study warrant further discussion.
First, it was a single-center phase II study. The lack of double-blind
design and placebo was also a weakness of the clinical trial. Moreover,
all three treatment groups were combined with hysteroscopic evaluation
and resection of endometrial lesion, which might conceal the difference
in efficacy of the regimens. In addition, the follow-up time after
complete response was relatively short. The rates of recurrence,
pregnancy and live birth will be further analyzed after all patients
have been followed up for two years. Finally, the rate of lost to
follow-up in our study is relatively high (26.6% and 17.1% at 16 weeks
and 32 weeks of treatment), which may reduce the accuracy of the
results. Some patients eventually delayed or cancelled the hysteroscopy
for various reasons, such as the COVID-19 quarantine, vaginitis, the
conflict with their working hours, resulting in a high rate of lost
follow-up.