Can uterocervical angles successfully predict induction of labor in nulliparous women?

PURPOSE: Induction of labor is a common practice in obstetrics. In recent years, a newer ultrasonographic parameter called the uterocervical angle (UCA) has been identified as a predictive tool for births. Our purpose is to investigate the role of UCA in predicting successful induction of labor.

METHODS: The nulliparous term pregnancies (n:150) were grouped into successful/failed inductions of labor based on their progress into the active phase of labor after the administration of prostaglandin E2 (dinoprostone). The pre-induction cervical length (CL) and UCA were compared in the two groups. The study population was further grouped according to their modes of delivery and pre-induction UCAs were compared among the subgroups.

RESULTS: The mean UCAs were not significant among the successful induction and failed induction groups (105.46 ± 20.54 degrees in the successful group and 110.57 ± 13.46 degrees in the failed group). However, UCAs significantly varied among the modes of delivery subgroups. The median UCA was significantly higher in patients who delivered vaginally after a successful induction of labor than in patients who delivered via cesarean section. The median UCA value was lowest in patients who had a successful induction of labor but ended up having a cesarean section (Fig. 2). Further, the duration of the active phase of labor negatively correlated with the UCA but not the CL (rho=-0.23, p = 0.02). There was also a negative correlation between the CL and the UCA in patients who delivered vaginally after successful induction of labor (rho= -0.21, p = 0.03).

CONCLUSION: The UCA is a promising ultrasonographic marker in obstetrics. Although the pre-induction UCA did not predict the outcome of labor induction, patients with broader pre-induction UCAs were prone to have a shorter duration of active phase. The pre-induction CL and UCA are inversely corraleted in nulliparous women who delivered vaginally after a successful induction of labor.