Polarimetric Colposcopy for Cervical Changes in Pregnancy

Inclusion Criteria: * Major patient. * Single pregnancy. * Baseline ≥ 20 amenorrhea week for group 1 and baseline ≥ 20 amenorrhea week and \<37 amenorrhea week for group 2. * Dating obtained by ultrasound of the 1st trimester. * Written and informed consent. * Group 1 (low risk): Asymptomatic patient benefiting from usual follow-up in the maternity hospital. \> Group 2 (high risk): Symptomatic patient with cervical changes objectified by endovaginal ultrasound of the cervix with an effective length of \<20mm. Asymptomatic patient with a history of premature delivery or late miscarriage and cervical changes objectified by endovaginal ultrasound of the cervix with an effective length of \<20mm." Exclusion Criteria: * Known uterine malformation or suspected uterine malformation. * Pregnancy circled. * Premature rupture of membranes. * Suspicion of chorioamnionitis. * Abundant active bleeding hindering the visualization of the cervix. * History of conization. * Imminent childbirth. * Known medical indication at a birth \<37 amenorrhea week (severe pre-eclampsia, severe intrauterine growth retardation, hemorrhagic placenta previa, fetal malformations,….). * Examination of the cervix under speculum not possible. * Lack of social coverage (AME). * Limited understanding. * Participation in another intervention research. \> Group1 (Low risk): * History of spontaneous premature labor. * History of late miscarriage. * History of premature rupture of membranes."