Please select the eligibility criteria that correspond to the clinical trial below.
Title: Cervical Pessary vs. Vaginal Progesterone in Preventing Preterm Birth Among Women Presenting With Short Cervix: An Open-label Randomized Controlled Trial
Brief Summary: The purpose of this randomized control trial is to determine whether cervical pessary plus vaginal progesterone is superior to vaginal progesterone alone in decreasing preterm delivery rate, and improving perinatal outcome, among women presenting with an asymptomatic mid-pregnancy short cervix, in singleton and twin gestations.

All women with singleton or twin pregnancies undergoing routine ultrasonography up to 24 completed weeks of gestation (for examination of fetal anatomy and growth) and diagnosed with cervical length of ≤25 mm in singleton, or ≤38 mm in twins, will be invited to participate in the clinical trial.

Women who meet eligible criteria will be invited to participate in the clinical trial.

Women will be randomly assigned into one of the following groups: group A (vaginal progesterone) or group B (vaginal progesterone + pessary).

Follow-up visits for ultrasound assessment of fetal growth and cervical length will be carried out every two weeks until 37 weeks of gestation.


Options:
A: Inclusion Criteria:

* Singleton pregnancy
* Minimal age of 18 years

Exclusion Criteria:

* Major fetal abnormalities (requiring surgery or leading to infant death or severe handicap)
* SROM at the time of randomization
* Cervical cerclage in situ
* Active vaginal bleeding
* Previous cone biopsy or cerclage
* Major uterine structural anomalies
* Placenta previa
B: Inclusion Criteria:

* patient with a short cervix equal to or less than 25 mm by transvaginal ultrasound
* gestational age between 18 (0/7) and 23 (6/7) weeks of gestation according to the results of the ultrasound of the first trimester, or by integrating the date of the last period
* patients who were informed of the study and agreed to sign the consent form.

Exclusion Criteria:

* pregnancy with a fetus with a major congenital malformation - regular and painful uterine activity - history of preterm premature rupture of membranes (PPROM) - active vaginal bleeding - complete and incomplete placenta previa - cerclage of the cervix in place - antecedent of conisation - multiple gestation - ballooning of membranes outside the cervix into the vagina - allergy/intolerance or hypersensitivity to progesterone or any of its ingredients - chronic medical conditions that would interfere with study participation or evaluation of treatment - vaginal administration of another drug.
C: Inclusion Criteria:

* Diagnosed to be pregnant at up to 24+0 weeks of gestation, with a cervical length measurement of ≤25 mm with a singleton pregnancy, or ≤38 mm in twins pregnancy.
* Does not meet with maternal/fetal/membrane/placental factors detailed in the exclusion criteria.
* Willingness to comply with the protocol for the duration of the study.
* Have signed an informed consent.

Exclusion Criteria:

* Fetal factors: major fetal abnormalities, death of one or both of the fetuses, twins- twin-to-twin transfusion syndrome, and severe growth retardation.
* Maternal factors: prophylactic cervical cerclage in situ, painful regular uterine contractions, active labor, active vaginal bleeding, maternal age under 18, uterine abnormalities (i.e. two cervices), and severe uterine prolapse.
* Membranes and placental factors: placenta previa, ruptured membranes.
D: Inclusion Criteria:

* Women with a singleton pregnancy and a history of at least one previous preterm delivery before 34+0 weeks and/or a history of at least one previous cervical surgery
* 12+0 - 16+0 weeks of gestation at time of randomization
* only women with minimum age of 18 and capable of giving consent

Exclusion Criteria:

* major fetal abnormalities
* uterine malformation, placenta previa totalis
* Cerclage prior to randomization
* At randomisation: active vaginal bleeding and/or spontaneous rupture of membranes and/or painful regular uterine contractions
* silicone allergy
* current participation in other RCT

Answer: C