Efficacy Study of a Cervical Pessary Containing Progesterone for the Prevention of Preterm Delivery

Participant selection will be performed by screening the general population of pregnant women with single fetus monitored by the Hospital Healthcare Network, to investigate by serial transvaginal ultrasound performed between gestation weeks 16 (0 day to 7 days) and 24 (0 day to 7 days) those patients who have a cervical length between 10 mm and 25 mm, and/or women with a single fetus and cervical length ≥10 mm presenting one or more of the following risk factors:

• preterm birth prior to 35 (34 weeks and 6 days) weeks of gestation;
• premature rupture of membranes prior to 35 (34 and 6 days) weeks of gestation.

After insertion of the pessary or beginning of the administration with vaginal progesterone capsules and until 28 weeks of gestation, participants in the 3 treatment groups will be monitored every 4 weeks at the most or more often, if the site has established so as a control standard. After 28 weeks, patients should be monitored every 2 weeks.

The proportions of spontaneous preterm delivery before gestation weeks 32 and 34 will be compared between the control group and the 2 groups with the pessaries containing different doses of progesterone.

Inclusion criteria

• Women with a single pregnancy and a cervical length of 10 mm - 25 mm between 16 and 24 weeks of gestation, without any previous factors.
• Women with a single pregnancy with 10 mm or more cervical length between 16 and 24 weeks of gestation, and pre-existing risk factors risk factors for preterm birth:
• Previous preterm birth before week 35.
• Previous rupture of membranes before week 35

Exclusion criteria

• Pregnancies with:

• Major fetal abnormalities, such as lethal malformations or malformations requiring pre- or post-natal surgery; and fetal death before inclusion into the study.
• History of rupture of membranes or prophylactic cerclage before study entry.
• Cervical or vaginal injuries prior to insertion of the pessary (e.g., cervical erosion secondary to trauma, infection, or carcinoma; vesicovaginal or rectovaginal fistulas).
• Unconscious, severely ill or mentally disabled patients, or under 16 years of age.
• Patients for whom use of progesterone is contraindicated.
• Patients with history of thrombosis.