Since that series, a number of investigators have used TAC in selected patients with cervical incompetence, and have reported similar results.2-4 These data suggest that, in selected patients, TAC is safe and effective at reducing the incidence of second-trimester pregnancy loss due to cervical incompetence.
There is no evidence, however, that TAC is superior to transvaginal cerclage as an initial procedure in the management of cervical incompetence. Furthermore, TAC is associated with far more morbidity than transvaginal cerclage. Not only does it require a laparotomy for placement, but subsequent cesarean delivery is necessary. For these reasons, TAC should be reserved for patients with documented cervical incompetence who have either failed previous transvaginal cerclage or in whom a transvaginal cerclage is technically impossible to place, e.g., when there is little of the anatomic cervix to work with.
Multiple cervical therapies for dysplasia, prior Manchester-Fothergill operation, or severe adenosis secondary to diethylstilbestrol (DES) exposure are other examples of situations in which the transvaginal approach to cerclage may be impossible.
Controversy 3
After placement, what follow-up is necessary?
Many approaches have been employed in the prophylactic-cerclage patient, all of them unencumbered by data. Empirically, many patients benefit from the freedom to carry on routine activities until 16 weeks’ gestation, at which time various restrictions are imposed, depending on the risk of preterm delivery.
The most frequently employed follow-up today is the ultrasound examination to assess cervical length, although its superiority to digital examination is not well-substantiated. Nevertheless, a cervical length that appears to be normal on ultrasound is very reassuring for the patient, and the benefit of such reassurance is difficult to quantify—but probably real.
After 24 weeks’ gestation, the need for follow-up of the cervix diminishes, since further surgical intervention would be unlikely. After this gestational age, surveillance will be mainly for preterm labor. Because it often is difficult to distinguish cervical incompetence from preterm labor, close surveillance for the latter is prudent and justified.
When it comes to emergent cerclage, patients initially tend to be hospitalized. Since the underlying problem necessitating the cerclage (infection, incompetence, concealed abruption) is rarely clear, the need for caution is greater. These patients generally benefit from close ultrasound surveillance and, as gestation progresses, close surveillance for preterm labor. Additional restrictions such as bed rest generally are imposed as well, but we lack data proving that they improve pregnancy outcome.
Retention of the cerclage may prolong latency, allowing for a more favorable gestational age at delivery. On the other hand, it also may provide a nidus for infection.
Controversy 4
What is the optimal time for removal?
Since the purpose of cerclage placement is to prevent prematurity, I generally recommend delaying removal until 37 weeks’ gestation, when the definition of “term” is met. There is no standard of care attached to this gestational age, and removal at 36 or 38 weeks is perfectly acceptable.
Too-early removal should be avoided, as this increases the possibility of a significantly premature delivery. It also is inadvisable to delay removal beyond 38 weeks, when the benefits of prolonging gestation are negligible and the risk of cervical damage with initiation of labor closer to term is increased.
Of course, if increased uterine activity at an earlier gestational age places the cerclage under tension, earlier removal is justified.
Controversy 5
Should the cerclage be removed if the membranes rupture?
The presence of a cerclage does not appear to increase the incidence of preterm premature rupture of membranes (PROM) remote from placement. On occasion, however, preterm rupture occurs with a cerclage in place. Retention of the cerclage may prolong latency, allowing for a more favorable gestational age at delivery. On the other hand, a retained cerclage may provide a nidus for infection.
Ludmir et al5 conducted a retrospective analysis of prophylactic McDonald cerclage in 30 singleton pregnancies complicated by preterm PROM between 24 and 32 weeks’ gestation. In 20 cases (67%), the cerclage was removed at presentation at the discretion of the attending obstetrician; in the remaining 10 cases (33%), the cerclage was retained until delivery. The difference in likelihood of delivery within 24 hours of presentation between the 2 groups was significant: 30% (6 of 20) in the removed versus 0% (0 of 10) in the retained group. The neonatal mortality rate in the retained group was 70% (7 of 10), however, compared with 10% (2 of 20) in the removed group (P<.001 seventy-one percent of neonatal deaths in the retained group were result early sepsis compared with removed>P<.001 neonatal mortality was not examined by gestational age.>
A more recent retrospective analysis of pregnancy outcomes in 81 patients with preterm PROM and preexisting cerclage between 24 and 35 weeks’ gestation suggested that the decision to remove or retain the cerclage had no effect on latency or perinatal outcome.6 Comparison of the cerclage patients with 162 control subjects with preterm PROM but no cerclage suggested that gestational age at presentation was the most important determinant of pregnancy outcome.6