The pathophysiology of human premature cervical remodeling resulting in spontaneous preterm birth: Where are we now?

Abstract

Approximately one in ten (approximately 500,000) pregnancies results in preterm birth (PTB) annually in the United States. Although we have seen a slight decrease in the U.S. PTB rate between 2007 to 2014, data from 2014 to 2015 shows the preterm birth rate has slightly increased. It is even more intriguing to note that the rate of PTB has not significantly decreased since the 1980s. In order to decrease the rate of spontaneous preterm birth (sPTB), it is imperative that we improve our understanding of normal and abnormal reproductive tissue structure and function and how these tissues interact with each other at a cellular and biochemical level. Since other chapters in this issue will be focusing on the myometrium and fetal membranes, the goal of this chapter is to focus on the compartment of the cervix. We will review the current literature on normal and abnormal human cervical tissue remodeling and identify gaps in knowledge. Our goal is also to introduce a revised paradigm of normal cervical tissue structure and function which will provide novel research opportunities that may ultimately lead to developing safe and effective interventions to significantly decrease the rate and complications of prematurity.

miR‑199a‑3p suppresses cervical epithelial cell inflammation by inhibiting the HMGB1/TLR4/NF‑κB pathway in preterm birth

“…compared with the normal population, pregnant women have increased susceptibility to pathogens in the environment, thus increasing the risk of adverse pregnancy outcomes (3). Inflammation, or more specifically inflammatory activation caused by infection or other factors, plays key roles in uterine activation and delivery (4), including promoting inflammatory factor responses and destroying the cervical epithelial barrier, thus inducing cervical remodeling (5). cervical remodeling is a natural, continually occurring process over the course of gestation, but the mechanism of its occurrence and progression remains largely unknown.…”

Position Paper of the Task Force for Obstetrics and Prenatal Medicine (AGG – Section Preterm Birth) on the Placement, Removal and Surveillance of the Arabin Cervical Pessary in Patients at Risk for Spontaneous Preterm Birth

“…The inner upper diameter should usually be 32 mm when treating average cervical shortening and, in rare cases, 35 mm (in patients with an unusually edematous wide cervix or U-shaped funneling) to avoid compression with further secretion of atypical interleukins and cytokine production 5 , 6 .…”

“…This means that in patients with a high risk for preterm birth, specific multi-resistant bacteria or streptococcus should be excluded in a timely manner. Romero et al stated that the vaginal microbiome is not associated with the microbiome in the intraamniotic cavity or an inflammation of the amniotic membranes, and not necessarily with preterm birth (PTB) 6 , 7 .…”

Development and Validation of a Model for Individualized Prediction of Cervical Insufficiency Risks in Patients undergoing IVF/ICSI Treatment

“…Although cervical weakness may be associated with a variety of events including cervical ablation, cervical excision or cervical hypoplasia after diethylstilbestrol [5] , most women diagnosed with CI actually have normal cervical integrity [6] . On the other hand, premature cervical ripening which can also be caused by subclinical infection, local in ammation, hormonal effects or genetic factors, is now the generally accepted cause of CI [4,5] . The initial signs in patients with CI are usually present before the experience of contractions or any other clinical symptom of miscarriage or preterm labor, so the opportunity of providing interventional treatment is limited.…”