Uterine electrical activity and cervical shortening in the midtrimester of pregnancy

Abstract

Objective: To determine whether a correlation exists between increased uterine electrical activity and cervical length (CL) in the midtrimester of pregnancy. Method: In this case-control study, 312 asymptomatic nulliparous women underwent both uterine electromyographic assessment and ultrasound CL measurement between the 16th and 23rd weeks of a singleton pregnancy. The outcome measure was the difference in ultrasound CL measurement between the women found to have uterine action potentials on electromyography and those who did not. Results: Action potentials were detected in 66 (21.1%) of the 312 women; and compared with the remainder of the study population, cervical length was significantly shorter in these women (35.7 ± 8.9 mm vs 38.8 ± 7.9 mm; P < 0.01 by the Mann-Whitney test). Conclusion: Ultrasound CL measurement in the midtrimester was significantly shorter in women with increased uterine electrical activity.