Novel device vs manual examinations for the measurement of cervical dilation in labor: a randomized controlled trial

Cervical dilation and changes in cervical dilation inform the management of labor, including decisions to admit a patient to the hospital, augment labor, or perform a cesarean delivery. Practitioners routinely measure cervical dilation subjectively using 2 fingers on manual examination; however, agreement of ≤1 cm between 2 observers has been reported as 60% to 91% previously in laboring women.

To evaluate the agreement among different providers' examinations using DilaCheck (interexaminer agreement) compared with interexaminer agreement between 2 manual examinations for cervical dilation of women in labor.

Women admitted in labor to a labor and delivery service were randomized to receive 2 cervical examinations from trained providers, using either a novel device (DilaCheck) or the standard manual examination. This randomized controlled trial compares a novel device with the standard method of manual examination for the measurement of cervical dilation. The novel device consisted of a string measuring tape suspended between 2 soft plastic rings worn on the index and middle fingertips. Interobserver agreement, defined as the agreement (exact, ≤1 cm [primary outcome], or ≤2 cm) in the numeric cervical dilation measurement obtained by 2 different examiners, was compared between the 2 groups.

A total of 42 women in labor were randomized, 21 to the novel device and 21 to the standard manual examination groups. The 2 device examinations agreed in 19% of cases, whereas manual examinations agreed exactly in 42.9% of cases (P=.10). Interobserver agreement of ≤1 cm was 61.9% vs 95.2%, respectively (P=.008). Interobserver agreement of ≤2 cm was 90.5% vs 100%, respectively (P=.15). Most interobserver disagreement was seen at 5 to 7 cm of cervical dilation.

A novel device, DilaCheck, intended for a more objective cervical assessment of women in labor did not improve interobserver agreement; in fact, it decreased it. Standard cervical dilation examinations result in poor interexaminer exact agreement, usually at best 50% or less. Clinical management should be based on clinical differences of >1 cm because, in general, 90% of cervical examinations will agree within 1 cm of each other. Given the importance of dilation measurements in the management of labor, continued innovation in this field would benefit women in labor and the providers caring for them; however, the puzzle remains unsolved.