Cervical Assessment for Predicting Preterm Birth—Cervical Length and Beyond

Abstract

Preterm birth is considered one of the main etiologies of neonatal death, as well as short- and long-term disability worldwide. A number of pathophysiological processes take place in the final unifying factor of cervical modifications that leads to preterm birth. In women at high risk for preterm birth, cervical assessment is commonly used for prediction and further risk stratification. This review outlines the rationale for cervical length screening for preterm birth prediction in different clinical settings within existing and evolving new technologies to assess cervical remodeling.

The Impact of Cervical Conization Size Followed by Cervical Length Changes on Preterm Birth Rates in Asymptomatic Singleton Pregnancies

“…18 Our comparisons of the PTB rates and pregnancy duration in women without and with cervical conization in the 1st cohort, when the USCL was not adjusted, were similar to the literature data showing no difference between these populations 24,26,29 Besides, the PTB rates of women with su cient CL (> 25 mm) were also similar to those of women without cervical conization, whereas the PTB rate signi cantly increased in women with a short cervix (≤ 25) in comparison with women without cervical conization, cervical conization in total and su cient CL (P < 0.001). Subsequently, we con rm that the results of studies demonstrating controversial impacts of cervical electrosurgical procedures on the PTB rates 11,12 in comparison to POs in population or internal controls were dependent on the volume of the CCS 20,56−59 and the USCL adjustment. 12,13,60 The proportion remaining pregnant in the survival curve was signi cantly lower among women with a short cervix between 32-37 weeks of gestation than in other groups with and without cervical conizations by the Gehan-Breslow-Wilcoxon test (P < 0.0001).…”

“…Subsequently, we con rm that the results of studies demonstrating controversial impacts of cervical electrosurgical procedures on the PTB rates 11,12 in comparison to POs in population or internal controls were dependent on the volume of the CCS 20,56−59 and the USCL adjustment. 12,13,60 The proportion remaining pregnant in the survival curve was signi cantly lower among women with a short cervix between 32-37 weeks of gestation than in other groups with and without cervical conizations by the Gehan-Breslow-Wilcoxon test (P < 0.0001). The survival curve demonstrating the pregnancy duration among women with the short cervix in this study was similar to ndings of Iams et al 13 who compared two groups adjusted for USCL ≤ 25 vs > 25 mm.…”

“…USCL was performed during the 16-18 weeks of pregnancy. The procedure was done following the technique described by Iams et al 13 , according to their recommendations 12,16 , and the measurements were repeated three times. Then, the average value was recorded.…”

“…1-3,6−8 An expected increasing trend of the global PTB prevalence is based on further improvements of healthcare systems worldwide with the establishment of statistics and registration of PTB in many developing and low-income countries. 1,6,9,10 Traumatized and shortened cervix due to surgical procedures such as cold knife biopsy, conization, and excisions were presented as a mechanical causative factor of the PTB 11,12 , and its predictor. [13][14][15] Further, transvaginal ultrasound cervical length (USCL) measurements were recommended by many professional societies to predict the PTB risks.…”

“…[13][14][15] Further, transvaginal ultrasound cervical length (USCL) measurements were recommended by many professional societies to predict the PTB risks. 12,16 Historically electrosurgical treatments of cervical pathologies were suggested as a risk factor of PTB [17][18][19][20][21][22][23] , although other studies showed an absence of their impact on pregnancy outcome(POs) [24][25][26][27][28][29] , with con icting opinions of experts 11,12,30 , because of the complexity of the PTB causative mechanisms. 31,32 Vaginal progesterone was recommended as noninvasive PTB prevention for asymptomatic women with a short cervix in the special clinical guideline from the Society for Maternal-Fetal Medicine Publications Committee 33 , whereas the use of pessaries has more than 60-years history since Cross 34 published successful results of the use of 'Bakelite' cervical ring in 13 cases to prevent habitual abortions due to cervical incompetence.…”