vaginal pessary versus expectant management for placenta previa

Conditions: Placenta Previa

Summary: the purpose of this study is to perform a large multi-center randomized trial comparing the role of vaginal pessary versus expectant management in women with placenta previa between 22w0d and 32w0d of gestation in prolonging gestation until ≥36 weeks. secondary outcomes will assess duration of antepartum admission, total blood loss, gestational age at delivery, type of cesarean delivery, and a composite neonatal outcome. the hypothesis is that the use of a vaginal pessary in patients presenting with placenta previa between 22-32 weeks will decrease delivery prior to 36 weeks as compared to expectantly managing these patients.

while the use of pessary in this scenario has not been previously assessed, it is reasonable to infer, from the data for use of pessary to prevent preterm birth, and the data regarding the efficacy of cervical cerclage in reducing bleeding and preterm birth in patients with placenta previa to this clinical conundrum. if cerclage improves pregnancy outcomes in patients with placenta previa, the use of a vaginal pessary should be a less-invasive but similarly efficacious alternative to maintain cervical length. the purpose of this study is to compare two treatment options reasonably used in clinical practice. use of cervical pessary is not expected to increase antenatal costs beyond the minimal cost of the pessary. additionally, given the results of the available clinical trials on cerclage maintaining cervical length and decreasing bleeding, this procedure has the potential to decrease the cost of both antepartum admissions for bleeding and neonatal care. a substantial number of women with placenta previa will not hemorrhage until they reach the third trimester, thus, by allowing for enrollment and pessary placement as late as 32w0d, the intervention may be applied to the broadest "at risk" population. as previously mentioned literature on the use of cerclage in patients with placenta previa and short cervix are limited by a reduced number of eligible subjects and concern over safety issues has not been assuaged by these small studies. as pessary placement appears to carry little if any risk based on a number of published studies, eligibility can be expanded to any cervical length.

Eligibility criteria:
inclusion criteria: * participant age 18 years or older * gestational age between 22w0d and 32w0d, inclusive, at time of enrollment * singleton pregnancy * complete placenta previa * intact membranes * no allergies to material in pessary * plan to deliver at pi's hospital * informed consent obtained, signed/dated exclusion criteria: * active preterm labor * nonreassuring fetal heart rate tracing * intrauterine fetal death * active bleeding (may be enrolled if hemostatic \>48 hours) * ruptured membranes * any fetal condition likely to cause serious neonatal morbidity independent of gestational age: fetal malformation likely to require surgery, fetal malformation involving vital organs, fetal viral infection, hydrops fetalis, * known uterine anomaly * cervical cerclage present at time of enrollment * maternal condition that warrant continued hospitalization (example severe preeclampsia, diabetes out of control, maternal heart disease)

Keywords: placenta previa vaginal pessary premature birth