Reproducibility and usability assessment of the novel Fine Birth device for threatened preterm labor diagnosis

BACKGROUND: Preterm delivery is considered the leading cause of mortality worldwide in children under 5 years old. Approximately 45 million pregnant women are hospitalized yearly for threatened preterm labor. However, only 50% of pregnancies complicated by threatened preterm labor end in delivery before the estimated date, classifying the rest as false threatened preterm labor. The ability of current diagnostic methods to pre-dict threatened preterm labor is low (low positive predictive value), ranging between 8% and 30%. This highlights the need for a solution that accu-rately detects and differentiates between false and real threatened preterm labors in women who attend obstetrical clinics and hospital emergency departments with delivery symptoms.OBJECTIVE: Primarily, this aimed to assess the reproducibility and usability of a novel medical device, the Fine Birth, aimed at accurately diagnosing threatened preterm labor through the objective quantification of pregnant women's cervical consistency. Secondarily, this study aimed to evaluate the effect of training and the incorporation of a lateral microca-mera on the device's reliability and usability outcomes.STUDY DESIGN: A total of 77 singleton pregnant women were recruited during their follow-up visits to the obstetrical and gynecologic departments at 5 Spanish hospitals. The eligibility criteria included preg-nant women aged >= 18 years; women with a normal fetus and uncompli-cated pregnancy; women without prolapse of membranes, uterine anomalies, previous cervical surgery, or latex allergy; and women signing the informed written consent. Cervical tissue stiffness was assessed using the Fine Birth device, whose technology is based on the propagation of torsional waves through the studied tissue. Cervical consistency measurements were taken for each woman until obtaining 2 valid meas-urements by 2 different operators. The intraobserver and interobserver reproducibilities of the Fine Birth measurements were assessed using the intraclass correlation coefficients with a 95% confidence interval and the Fisher test P value. The usability was evaluated on the basis of the clini-cians' and participants' feedback.RESULTS: There was good intraobserver reproducibility (intraclass cor-relation coefficient, 0.88; 95% confidence interval, 0.84-0.95; Fisher test P value<.05). As the results obtained for the interobserver reproduc-ibility did not reach the desired acceptable values (intraclass correlation coefficient of <0.75), a lateral microcamera was added to the Fine Birth intravaginal probe, and the operators involved in the clinical investigation received the corresponding training with the modified device. The analysis of 16 additional subjects demonstrated excellent interobserver reproduc-ibility (intraclass correlation coefficient, 0.93; 95% confidence interval, 0.78-0.97) and an improvement after the intervention (P<.0001).CONCLUSION: The robust reproducibility and usability results obtained after the insertion of a lateral microcamera and the correspond-ing training make the Fine Birth a promising novel device to objectively quantify the patient's cervical consistency, diagnose threatened preterm labor, and, thus, predict the risk of spontaneous preterm birth. Further research is needed to demonstrate the clinical utility of the device.

Automated summary

This study evaluated the reproducibility and usability of a novel medical device, the Fine Birth, for accurately diagnosing threatened preterm labor through objective quantification of cervical consistency in pregnant women. The results showed good intraobserver reproducibility and excellent interobserver reproducibility after adding a lateral microcamera and providing training.