Digital Mueller Polarimetric Colposcopy For High-Performance Detection Of Premature Birth – DigitMC-PB

Prematurity represents the first cause of perinatal mortality and morbidity worldwide. The estimated rate of prematurity is about 6% in France and Europe and it is two times greater in US. This rate remained stable over the last two decades, despite the improvement of diagnosis by using transvaginal ultrasound and the emergence of innovative tocolytic treatments. The Threat of Premature Birth (TPB) is the most important complication during pregnancy. It occurs between 23 and 36 amenorrhea weeks and is manifested by uterine contractions associated with modifications in the cervix with or without bleeding and/or premature rupture of the membranes. In the absence of medical intervention by tocolysis, the installation of regular uterine contractions may result in premature delivery. However, for women diagnosed with TPB, actual premature delivery occurs in 15% to 50% of the cases.
The most widely-used technique to diagnose and evaluate the severity of the TPB is the transvaginal ultrasound of the cervix. This technique, which involves measuring the cervical length, has been recommended since 2002 by the “Collège National des Gynécologues et Obstétriciens de France”. However, due to the imperfect correlation between this measurement and the time remaining before birth, the choice of a threshold for the cervical length used to detect a preterm delivery is strongly practitioner-dependent. Consequently, a large percentage of women suspected of TPB undergoes unnecessary hospitalization which is costly and can feature specific complications, like thromboembolic risks due to bed confinement, as well as side effects of tocolytic treatments. Finally, it is worth mentioning that prematurity remains a major health problem worldwide due to the inadequacy of current medical procedures used to prevent and manage it.
The microscopic structure of the uterine cervix determines its mechanical properties at macroscopic scale during gestation: 1) prior to the term it must remain closed and resist the increasing mechanical stress due to the growing fetus; 2) at term, it must become soft to deform and dilate for enabling the delivery (cervical ripening). Uterine cervix is mainly composed of connective tissue. It consists of two different microscopic structures: a cellular component and the extracellular matrix, this latter being mainly constituted by collagenous fibers. Several studies demonstrated that cervical ripening is mainly due to a collagen remodeling process. It is characterized by a disorganization of collagen and a considerable decrease of its concentration (about 60% less compared with non-pregnant women). A premature remodeling of collagen is hypothesized to be the main cause of preterm delivery.
An innovative tool is needed to monitor the remodeling of cervical collagen in vivo for pregnant women in order to provide an objective method for detecting the actual risks of prematurity and accurately predict the time remaining before childbirth.
The key point of the proposed study lies in the fact that Mueller polarimetric imaging can be well suited for address the previously mentioned issue. It is an optical imaging technique based on the analysis of the modifications induced by a sample on the polarization of the light used to explore it. In our previous studies we widely demonstrated the potential of Mueller polarimetric imaging for detecting the modifications in cervical collagen due to the presence of a premalignant lesion. Finally our very recent results showed that this technique is promising also for detecting and quantifying cervical collagen remodeling during pregnancy.
The main objective of this study is to determine the best “polarimetric biomarkers” enabling to define the optimal “PS” reflecting the status of cervical collagen throughout its remodeling process due to pregnancy in order to improve the detection of TPB and accurately predict the time remaining before childbirth.