Strengths and limitations
The strengths of our study are that it is
a retrospective, cohort study
matched with the degree of cervical dilation in ECC technology in twin
pregnancy, which undertook a subgroup analysis for cervical dilation ≥
3cm and < 3cm. There are no prior dedicated retrospective,
cohort matched studies in this population. Our study adds to the current
limited literature on ECC technique in twin pregnancies. Despite the
small sample size, we were able to show a significant benefit of this
novel technique in twin pregnancies with cervical dilation 1-6cm.
Furthermore, our study proposed
the potential benefit of this novel technique even in women with
cervical dilation ≥3cm and prolapsed membranes, in whom had a high
chance of sPTB before 28 weeks and we first to suggest that ECC
placement may be extended to 26 weeks of gestation in twins. Also, our
study does have some limitations. Firstly, because of the retrospective
nature of this study, selection bias was inevitable despite our attempts
to reduce this by matching one-on-one with controls. Secondly, there
could be a potential concern that the patients considered subjectively
to have a higher risk of PTB tend to receive combined McDonald-Shirodkar
procedure, resulting in possible selection bias. However, the clinical
characteristics between the two groups were similar, suggesting that
selection bias was minimal. Due to these limitations, future randomized
control studies with large samples are warranted to evaluate the
efficacy of each treatment and confirm our findings.
Conclusions: In addition, we suggested that ECC placement may
be extended to 26 weeks of gestation in twin pregnancy. ECC performed
with the combined McDonald-Shirodkar methord in twins with cervical
dilation 1-6 cm may reduce the rate of sPTB and improve perinatal and
neonatal outcomes compared with McDonald procedure, especially for twins
with cervical dilation of 3-6 cm and prolapsed membranes.