Fetal Adrenal Gland Volume a Novel Predictor of Onset of Labor

The importance of fetal adrenal gland volume measurement in successful labor induction with oxytocin

AIM

We aimed to show the predictive value of fetal adrenal gland volume (FAGV) measurement in the success of labor induction with oxytocin.

METHODS

This is a prospective cohort study that included a total of 103 term nulliparous. Immediately after deciding to induce labor with oxytocin, the fetal right and left adrenal gland measurements were obtained.

RESULTS

Induction success was achieved in 89 of 103 (86.4%) pregnant women. In comparison of the FAGV values of failed induction labor group, the total volumes of right and left fetal adrenal glands and the fetal zone volumes (FZV) were found to be statistically significantly higher in the successful labor induction group (p < 0.001). In predicting induction success, the cut-off value of fetal adrenal gland volume (cFAGV) was set as >230.2 mm³ /kg and area under curve (AUC) value of 0.872 (95% confidence interval [CI], 0.736-1.000) for right total adrenal gland (p < 0.001). The cut-off value of cFAGV was set as >236.7 mm³ /kg and AUC value of 0.891(95%CI, 0.768-1.000) (p < 0.001) for left total adrenal gland. The cut-off value of cFAGV was set as >12.6 mm³ /kg and AUC value of 0.952 (95%CI, 0.905-0.999) for right FZV(p < 0.001). The cut-off value of cFAGV was set as >7.8 mm³ /kg and AUC value of 0.884 (95%CI, 0.752-1.000) for left FZV (p < 0.001).

CONCLUSIONS

Two-dimension ultrasonographic measurement is an easy-to-access and noninvasive method that can be integrated into the algorithms to predict the success of induction based on FAGV measurement.

Predictive factors of labour onset using ultrasonography

We analysed the effectiveness of transvaginal ultrasonographic and foetal/maternal pulse Doppler findings as predictors of labour onset within 1 week. We included 22 single normal pregnancies and evaluated the one-point and short- and long-term differences in uterine artery pulsatility index (PI), umbilical artery PI, middle cerebral artery PI (MCA-PI), peak systolic velocity, and cervical length (CL). Presence of funnelling and membrane separation over the internal cervical os was evaluated. Significant changes were observed in the one-point measurement of and short-term and long-term differences in CL, the one-point measurement of and long-term difference in MCA-PI, and the presence of membrane separation (Grade 2). In multivariate analysis, the significant predictors were short-term differences in CL (odds ratio [OR]: 5.27), long-term differences in MCA-PI (OR: 13.3), and presence of membrane separation (Grade 2) (OR: 5.38). Transvaginal ultrasonographic and foetal pulse Doppler findings were effective predictors of labour onset within 1 week.Impact statementWhat is already known on this subject? Parameters reported to predict labour onset include the Bishop score, cervical length, decreased long-term cervical length, funnelling of the internal cervical os, and adrenal gland volume.What do the results of this study add? Short-term changes in cervical length, long-term changes in middle cerebral artery pulsatility index, and the presence of membrane separation Grade 2 were found to be useful predictive factors of labour onset in this study.What are the implications of these findings for clinical practice and/or further research? The prediction of labour onset enables clinicians to properly manage pregnancy and delivery considering maternal and foetal conditions.