Please select the eligibility criteria that correspond to the clinical trial below.
Title: Cervical Pessary for Prevention of Spontaneous Preterm Birth in Singleton Pregnancies With Arrested Preterm Labor: a Randomized Controlled Trial
Brief Summary: Preterm birth (PTB) is a major cause of perinatal morbidity and mortality. Worldwide, about 15 million babies are born too soon every year, causing 1.1 million deaths, as well as short- and long-term disability in countless survivors.

Different strategies have been studied for prevention of spontaneous PTB (SPTB) in randomized controlled trials (RCTs), including progesterone, cerclage, cervical pessary, as well as lifestyle modification, such as smoking cessation, diet, aerobic exercise, and nutritional supplements. Most successful effort to reduce the incidence of SPTB have focused on asympatomatic women with risk factors, such as prior SPTB or short cervix. However, most SPTB occur in symptomatic women, i.e. women with preterm labor (PTL). Women with arrested PTL are at increased risk of SPTB.

The cervical pessary is a silicone device that has been used to prevent SPTB. The leading hypotheses for its mechanisms are two: that the pessary helps to keep the cervix closed, and that the pessary changes the inclination of the cervical canal so that the pregnancy weight is not directly above the internal os.

The aim of the study is to assess the efficacy of pessary in reducing preterm birth in women with arrested preterm labor


Options:
A: Inclusion Criteria:

* Singleton gestations
* Diagnosis of arrested PTL
* 18-50 years of age
* TVU CL ≤25mm at the time of randomization

Exclusion Criteria:

* Multiple gestations
* Rupture of membranes at the time of randomization
* Known major fetal structural (i.e. defined as those that are lethal or require prenatal or postnatal surgery) or chromosomal abnormality
* Fetal death at the time of randomization
* Cerclage in situ at the time of randomization
* Pessary in situ at the time of randomization
* Vaginal bleeding at the time of randomization
* Women who are unconscious, severly ill, mentally handicapped, or under the age of 18 years
* Placenta previa and/or accreta
* Ballooning of membranes outside the cervix into the vaginal or TVU CL = 0mm at the time of randomization
* Painful and regular uterine contractions at the time of randomization
B: Inclusion Criteria:

* Women with a pregnancy and a history of at least one spontaneous preterm birth before 34+0 weeks and/or a history of late abortion
* 12+0 -18+0 weeks of gestation
* Minimal age of 18 years
* Informed consent signature

Exclusion Criteria:

* The previous preterm delivery is iatrogenic proterm labor
* Major fetal abnormalities (requiring surgery or leading to infant death or severe handicap)
* The pregnant woman with severe cervical erosion, cervical polyp, hemorrhage and the doctors think she could not use cerclage pessary
* The pregnant woman with uterine cervicitis
* The pregnant woman that has been confirmed premature birth
* Cerclage prior to randomisation
* Cerclage prior to randomisation
* Placenta previa totalis
* Active vaginal bleeding at the moment of randomization
* Spontaneous rupture of membranes at the time of randomization
* Silicone allergy
* Painful regular uterine contractions
* The pregnant woman have the indication of operation cervical cerclage
* Current participation in other RCT
C: Inclusion Criteria:

* 18-50 years of age
* Singleton pregnancy (limits the participants to female gender)
* Short cervical length (less than or equal to 25 mm) on second trimester transvaginal ultrasound at 18-23 6/7 weeks gestation

Exclusion Criteria:

* Multiple gestation
* Prior spontaneous preterm birth 16-36 6/7 weeks
* Ruptured membranes
* Lethal fetal structural anomaly
* Fetal chromosomal abnormality
* Cerclage in place (or planned placement)
* Vaginal bleeding
* Suspicion of chorioamnionitis
* Ballooning of membranes outside the cervix into the vagina or CL = 0 mm on transvaginal ultrasound
* Painful regular uterine contractions
* Placenta previa
D: Inclusion Criteria:

* 18-50 years of age
* Singleton pregnancy (limits the participants to female gender)
* Short cervical length (less than or equal to 25 mm) on second trimester ultrasound at 18-23 6/7 weeks gestation

Exclusion Criteria:

* Multiple gestation
* Prior spontaneous preterm birth 16-36 6/7 weeks
* Ruptured membranes
* Lethal fetal structural anomaly
* Fetal chromosomal abnormality
* Cerclage in place (or planned placement)
* Vaginal bleeding
* Suspicion of chorioamnionitis
* Ballooning of membranes outside the cervix into the vagina or CL = 0 mm on transvaginal ultrasound
* Painful regular uterine contractions
* Placenta previa

Answer: A