Removal Versus Retention of Cerclage in Preterm Premature Rupture of Membranes (PPROM)

The placement of cervical cerclage is standard of care for women who experience incompetent
cervix. Treadwell et al, published the largest retrospective review of 482 patients
receiving cerclage (364 elective and 118 emergent). They found premature rupture of
membranes (PROM) in 38% of the subjects with 9% delivering <27 weeks. Preterm birth is the
cause of at least 75% of neonatal deaths that are not due to congenital malformations. The
question of whether to remove cerclage after preterm premature rupture of membranes (PPROM)
is one of the unresolved controversies in obstetrics because the few available studies are
retrospective, all have small numbers of patients, and the studies have given conflicting
results regarding the safety of retaining a cerclage after preterm premature rupture of the
membranes. It is unclear from the retrospective studies whether latency (the interval from
membrane rupture to the onset of labor) is prolonged with retention of the suture.
Furthermore, some, but not all studies suggest an increase in major infectious maternal
morbidity and possibly neonatal morbidity. For this reason, clinicians vary greatly in
deciding on whether to remove a cerclage in a patient with PPROM and either practice is
currently an acceptable standard. This is a fairly rare complication, the combination of
PPROM in a patient with cerclage in place only occurs in about 1-3/1000 pregnant women.
Thus it has been impossible to study this problem prospectively in any single institution.
The establishment of the Obstetrix Collaborative Research Group affords the unique
opportunity to study this rare complication. Obstetrix manages 19 practices of
Perinatologists around the U.S. and Mexico and is comprised of nearly 100 such
subspecialists. This problem is most often referred to a Perinatologist when it occurs, so
it is not unusual for these practices to see 5 - 10 such patients per year. Obstetrix fully
funds the infrastructure of this research group and inclusion in this study will not alter
the cost of patient care in either group as there is virtually no cost in removing the
cerclage and all these patients are kept in hospital until delivery when membranes rupture
as standard of care.

This is a multicenter trial. The purpose is to determine whether retention of cerclage
after preterm premature rupture of the membranes improves latency (without a significant
increase in chorioamnionitis) and lessens neonatal morbidity.

Inclusion Criteria:

1. A previously placed prophylactic cerclage defined as any cerclage done < 23 6/7 weeks
including those done for previous history of cervical incompetence, asymptomatic
cervical shortening (regardless of effacement) and asymptomatic cervical dilation <
3 cm

2. Spontaneous rupture of membranes 22-32 weeks

3. Singleton or twin gestation

4. Shirodkar or McDonald cerclage in place > 1 week

Exclusion Criteria:

1. Active labor (> 8 uterine contractions [UCs] per hour)

2. Chorioamnionitis as defined by temperature > 38 plus fetal tachycardia or uterine
tenderness

3. Placenta previa or undiagnosed vaginal bleeding

4. Nonreassuring fetal status by nonstress test (NST) or biophysical profile (BPP)

5. Mature pulmonary studies

6. Positive gram stain, culture, white blood cells (WBC) > 30, or glucose < 14 on
amniocentesis

7. Major fetal anomaly

8. Presentation > 48 hours after rupture of membranes

9. abdominal cerclage

10. Cerclage done for symptomatic cervical dilation (cervix dilated > 3 cm)

11. Post amniocentesis membrane rupture (rupture which occurs within one week of
amniocentesis)