Risk factors for unsuccessful vaginal birth after caesarean at full dilatation

The purpose of this study was to determine the risk factors for caesarean sections in the second stage of labour after a previous caesarean section among women who underwent trial of labour (TOL).

From a total of 639 women who experienced one caesarean section, 456 women were qualified for TOL. From this group, 105 women were subjected to a caesarean section in the first stage of labour and another 351 women reached the second stage of labour. From the latter group, 309 women delivered naturally and 42 were subjected to a caesarean section.

Risk factors for the necessity of performing a caesarean section in the second stage of labour after a previous caesarean section was the weight gain during pregnancy (OR = 1.07), the height of fundus uteri (OR = 1.25) before delivery, and the estimated foetal weight (OR = 1.01), a past delivery of a child with a birth weight exceeding 4.000 g (OR = 2.14), the presence of pre-gestational diabetes (OR = 15.4) and gestational diabetes (OR = 2.22), necessity of applying a delivery induction (OR = 2.52), stimulation of uterine activity during delivery (OR = 2.43) and application of epidural analgesia (OR = 4.04). A factor reducing the risk of a caesarean section in the second stage was a vaginal delivery in a woman's history (OR = 0.21).

Women should be encouraged to deliver naturally after a previous caesarean section, especially when their history includes a vaginal delivery and if there is no need for labour induction.