Emergency cervical cerclage in delayed-interval delivery of twin pregnancies: a scoping review

A literature search retrieved 102 potentially relevant articles. After screening and removing duplicate and irrelevant articles, 22 studies meeting the inclusion criteria remained. Among these, the studies involving cerclage procedures reported significantly longer intervals between intertwin deliveries compared to studies without cerclage. While the cerclage group also exhibited tendencies for lower rates of chorioamnionitis and maternal complications, these differences were not statistically significant compared to the non-cerclage group.

In 19 of the 22 articles, the interval duration was longer in the cerclage group than the non-cerclage group, with statistical significance. When the opposite result was obtained (3 articles), there were some cases of lower F1 gestational age and some cases of lower CRP and WBC, important predictors of chorioamnionitis, in the non-cerclage group. The cases of emergency cerclage were divided into two groups, those with a mean interval duration shorter than 50 days and those longer than 50 days. We found that the group with the longer interval duration had a lower F1 gestational age at delivery, lower maternal age, and lower incidence of chorioamnionitis than the group with the shorter interval duration given the same obstetric management measures. Thus, we hypothesize that in younger women, cases in which F1 is delivered earlier, cases without infection, and cases with emergency cerclage are more likely to have a longer interval duration and a better outcome for the remaining fetus. Although the present study has a small sample size, some previous studies may provide some support for this hypothesis. Zhan et al. [33] suggested that the gestational age of F1 largely determines the outcome of F2; the lower the gestational age of F1 at delivery and the longer the interval between F1 and F2, the better the outcome of F2. Rosbergen et al. [34] suggested that a lower gestational age of F1 is associated with a longer interval and better birth outcome of F2. Farkouh et al. [9] reported a longer delivery interval in cases of lower gestational age of F1. Similarly, de Jong et al. [35] reported better F2 outcomes in cases of early F1 delivery. de Frias et al. [18] reported the longest interval (154 days) and the lowest gestational age at delivery (15.1 weeks). Imachi et al. [20] believed that prevention of chorioamnionitis is the most important aspect of delayed-interval delivery, whereas Abboud et al. [32] suggested that infection is the factor that is the most determinative of outcomes.

Conservative management of delayed-interval delivery includes high ligature of the F1 umbilical cord with absorbable suture, antibiotics to prevent infection, tocolytics, promotion of fetal lung maturation, fetal preservation with progestogens, fetal neuroprotection with magnesium sulfate, bed rest, prophylactic anticoagulation, and so on. Singh et al. [22] and Api et al. [21] both suggested the use of absorbable suture and F1 umbilical cord ligature as close to the cervix as possible under aseptic conditions to prevent ascending infection. Rupture of the F1 amniotic sac after F1 delivery exposes the mother and F2 to the risk of ascending infection [36], and the lack of blood supply in the reproductive tract or necrotic tissue may provide opportunities for growth of Escherichia coli, Streptococcus, and Enterococcus faecalis and intrauterine infection [37]. Thus, most researchers recommend the selection of an appropriate antibiotic based on the results of cervical secretion culture as well as prophylactic antibiotic treatment even without indications of infection [38]. Although no standardized dosing regimen has been established, intravenous dosing for 3 days followed by oral dosing for at least one week is most common. Subsequent signs of infection, such as uterine tenderness, elevated WBP, CRP, and erythrocyte sedimentation rate, and fever, may require reintroduction of antibiotics. The success of delayed-interval delivery using emergency cerclage depends mainly on the prevention of possible subclinical infections and tocolysis [26]. Currently, tocolytics and antibiotics are both conservative treatments in the routine management delayed-interval delivery [39]. A systematic review and network meta-analysis of 95 randomized controlled trials on tocolytic therapy for preterm delivery by Haas et al. [40]. showed that calcium channel blockers (nifedipine) and prostaglandin inhibitors (indomethacin) were the most effective for prolonging the interval and improving neonatal outcomes. Calcium channel blockers were most beneficial for neonatal outcome while prostaglandin inhibitors caused the fewest maternal side effects. Magnesium sulfate and β-agonists were slightly less effective than these two, with β-agonists causing the most maternal side effects. Few cases of combined use of tocolytics have been reported, and co-administration may increase the probability of side effects. When preterm delivery risk of F2 is high, glucocorticoids can be administered to prevent the development of hyaline membrane disease and infant respiratory distress syndrome. When the fetus is less than 22 weeks of gestation with few primitive alveoli, glucocorticoids should not be used to avoid adverse effects. At a gestational age of 22–23 weeks, a course of prenatal treatment can be given. Raposo et al. [41] and Graham et al. [42] recommended promoting fetal lung maturation at F2 gestational age of 24 weeks, while Doger et al. [43] suggested that glucocorticoids should be used at F2 gestational age of 26 weeks. Louchet et al. [44] suggested that fetal lung maturation treatment should be administered from 24 weeks of gestation, and they also suggested an additional course of treatment around 28 weeks of gestation. Magnesium sulfate can protect the fetal brain and nerves and reduce the risk of cerebral palsy by stabilizing fetal cerebral circulation, and the use of magnesium sulfate for fetal neuroprotection has been reported since 1995 [45].

Bed rest is considered an alternative to cervical cerclage. Raposo et al. [41], Cozzolino et al. [46], and Doger et al. [43] concluded that strict bed rest should be applied until F2delivery; however, this is difficult to achieve and has low patient compliance, and it may cause complications such as thrombosis [28]. Five articles included bed rest, and two also included anticoagulation treatment for the mother. The American College of Obstetricians and Gynecologists Practice Bulletin No. 144 states that routine hospitalization and bed rest are not recommended for women with uncomplicated twin pregnancies and that prolonged bed rest may lead to thrombosis and deconditioning [47]. One study showed that emergency cerclage was superior to bed rest with respect to prolonging the delivery interval, preventing preterm delivery before 34 weeks and reducing the risk of neonatal complications [48].

The included articles had longer delivery intervals (but the difference was not statistically significant) and a lower incidence of chorioamnionitis among the cerclage group compared to the non-cerclage group. In a retrospective analysis of cases of delayed delivery of the retained fetus after loss of the first fetus by Doger et al. [43], 20 patients were divided into a cerclage and a non-cerclage group, and it was found that emergency cervical cerclage after delivery of F1 was associated with longer delivery intervals and higher F2 weight. Moreover, there was no statistical difference between the two groups in terms of F2 delivery week, live birth rate, take-home baby rate, and chorioamnionitis ratio. Zhang et al. [49] reviewed 66 primary reports from 7 case series and found that patients who underwent emergency cervical cerclage had statistically significantly longer delivery intervals, and emergency cervical cerclage did not significantly increase the risk of intrauterine infection after controlling for factors such as F1 gestational age, class of antibiotic, and use of tocolytics. Most researchers believe that the decision to perform emergency cervical cerclage should be made within 2 h after delivery of F1 [21, 50, 51]. Doger et al. [43]. suggested a McDonald cerclage should be placed if the cervix is effaced more than 70% or if the F2 amniotic membrane is prolapsed and needs to be pushed back into the uterine cavity, and a Shirodkar cerclage should be placed if the cervix is effaced 60% or less and the F2 amniotic membrane is not compressing the cervix. In addition, a meta-analysis of the conditions under which emergency cervical cerclage is indicated suggested that emergency cervical cerclage can help prolong pregnancy and reduce preterm delivery in cases of a cervical length of less than 15 mm in twin pregnancy or a cervical dilation of over 10 mm, whereas the benefit of emergency cervical cerclage in twin pregnancies with normal cervical length remains to be proven [52].

The most common maternal complication in delayed-interval delivery is infection, with approximately 22% of patients developing inflammatory conditions such as chorioamnionitis, thrombophlebitis, and endometritis, nearly 10% developing postpartum hemorrhage, and 6% developing placental abruption [53]. Although cervical cerclage has been suggested to increase the risk of infection and premature rupture of membranes, the included articles did not report this tendency, and patients who underwent cerclage appeared to have a longer interval between deliveries. Emergency cervical cerclage was not effective in delaying pregnancy in some of the cases analyzed here, where the mother either delivered the first fetus at a later gestational age or exhibited signs of infection. Therefore, strict control of infection is necessary to achieve the desired outcome of the cerclage.

The limitations of the present study include: (1) small sample size; (2) recall bias and measurement bias inherent to retrospective studies; (3) publication bias because articles concluding that emergency cerclage is effective are more likely to be published.