Mueller polarimetric colposcopy appears to be a powerful tool for evaluating cervical microstructure modification during pregnancy. Some polarimetric parameters of the uterine cervix can be correlated with the gestational age. The uterine cervix's polarimetric analysis could make it possible to accurately predict the term of childbirth and be used as a screening tool for preterm birth.

Interventional research protocol involving the human person relating to a medical device. This is a prospective, not randomized, monocentric study. Prematurity accounts for around 11% of births worldwide. In France, around 60,000 children (7.4%) are born each year prematurely. The term of gestation has a strong impact on mortality, severe neonatal morbidity, and child development. For this reason, premature birth represents a major public health issue. The means to reliably predict a premature birth are still ineffective. The medical device used in this research is a Mueller polarimetric colposcope which appears to be a powerful tool for evaluating the process of remodeling of cervical microstructure during pregnancy.

Mueller polarimetric imaging is the only technique that enables obtaining the comprehensive polarimetric characterization of a sample. Two groups are considered for this study: i) patients at low risk of premature birth (Group 1); ii) patients at high risk of premature birth (Group 2).

This study's main objective is to determine, for the two groups of patients, the best "polarimetric biomarkers" which make it possible to define an optimal "polarimetric score" reflecting the state of the cervical microstructure throughout its remodeling process during pregnancy.

This "Polarimetric Score" will be able to predict the term of childbirth and used as a screening tool for prematurity.

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."