Phosphorylated IGFBP-1 in predicting successful vaginal delivery in post-term pregnancy.

Purpose: To estimate whether phosphorylated IGFBP-1 (phIGFBP-1) in cervical secretion in term and post-term pregnancies can predict spontaneous onset of labor or vaginal delivery.

Methods: A prospective cohort study of 167 women in singleton term and post-term pregnancies, was conducted at 1st Department of Obstetrics and Gynecology, Medical University of Warsaw, between 2013 and 2014. phIGFBP-1 test (Actim Partus Medix Biochemica), ultrasound cervix assessment and Bishop score were analyzed in the study group. Spontaneous onset of labor was the primary and vaginal delivery was the secondary outcome.

Results: In 32.5 % of patients, spontaneous uterine contractions appeared. 67.5 % of women delivered vaginally, 32.5 % had cesarean section. phIGFBP-1 test predicted spontaneous onset of labor (sensitivity 0.69, specificity of 0.42) and successful vaginal delivery (0.67, 0.48). In the prediction of spontaneous delivery onset ultrasound cervical assessment and phIBFBP-1 had comparable sensitivity and in the prediction of successful vaginal birth all three tests had comparable sensitivity. The time from preinduction to spontaneous onset of delivery was significantly shorter in women with positive phIGFBP-1 test (13.65 ± 6.7 vs 20.75 ± 2.6 h; p = 0.006).

Conclusion: A test for phIGFBP1 presence might be an additional tool for predicting both spontaneous onset of labor and successful vaginal delivery in post-term pregnancies.