Introduction
Twins account for 0.5–4.0% of all births, in the last decade, the rate
of twin pregnancies has increased substantially in China1 2 ,3 . During 2012 to
2020, the twinning rate increased by 13.3% from 2.84 to 3.22 per 100
total births4 .
Since fertility policy had changed in China from two-child policy in
2014 and three-child policy in 2021, the rate of multiple births has
shown an upwards
trend5 .Twin pregnancies are associated with 50% incidence of preterm birth
(PTB) and at increased risk for low birth-weight (LBW), they are five
times more likely to have early neonatal and infant death and
complications related to prematurity and
LBW6 The most
important risk factor for PTB in twins is short cervical length prior to
24
weeks7-9 .
Twin pregnancies with cervical dilation ≥1cm in the second trimester are
associated with a poor prognosis, and more than 90% will result in
sPTB10-13 . The data on the efficacy of cervical
cerclage based on dilated cervix is limited in twin pregnancies, whereas
it is widely accepted in singleton pregnancies. In 2019, the Society of
Obstetricians and Gynaecologists of Canada
(SOGC)10 and in
2022 ,the Royal College of Obstetricians Gynaecologists (RCOG)14 suggested that
emergency cervical cerclage (ECC) as a salvage measure in both singleton
and multiple gestations, when the cervix is dilated to >1cm
without contractions. So ECC represents one of the best-commonly
surgical interventions to prevent sPTB in obstetrics. While the
technique has been widely studied and evaluated, controversy remains
regarding certain aspects of the therapeutic indication and
complementary management tests to be
performed15-20 .
Currently, two most commonly performed cerclage procedures are
modifications of Shirodkar and
McDonald21 ,22 . ECC may have higher chance of
failure and other complications such as preterm premature rupture of
membranes (PPROM), chorioamnionitis are more
common23 ,24 . It has been suggested that
cerclage placement closer to the internal os may be associated with
improved perinatal
outcome25 ,26 . Unlike the known methods, our
novel technique is characterized by a combination of the Shirodkar and
McDonald’s techniques, application of a cervical balloon dilator
(Aiyuan) to replace the membranes into the uterus before placement of
Shirodkar suture. The aim of our research is to compared the
effectiveness of this novel
technique to McDonald method, and to observe whether this ECC technology
has the best maternal and neonatal outcomes in twins with cervical
dilation of 1-6cm and/or prolapsed membranes without contraction between
18-26 weeks of gestation.