Labour induction at 40 weeks shows higher vaginal birth rate in women with previous caesarean scar
The optimal delivery timing for women with a previous caesarean section without maternal or foetal complications is not well studied. Obstetric Societies recommend a labour after caesarean section (TOLAC) for all eligible cases, and guidelines are available for eligibility for TOLAC. The Royal College of Obstetricians and Gynaecologists (RCOG) recommends 41 weeks to terminate these eligible patients if they do not go into spontaneous labour by the expected delivery date. Spontaneous labour is considered safer and has a higher chance of successful vaginal birth after caesarean (VBAC) than induced. Spontaneous labour is considered safer and has a higher chance of successful vaginal birth after caesarean (VBAC) than induced.
Authors undertook a pilot randomized controlled trial to compare the successful vaginal birth rates in women with previous one lower segment CS when induced at 40 weeks compared to expectant management till 41 weeks.
They conducted this parallel design nonblinded, randomized controlled trial in a tertiary care teaching institution in South India on women with a previous lower segment caesarean section eligible for a trial of labour with singleton foetus without any pregnancy complication at recruitment. They screened 1886 women. Sixty women underwent block (of 6 each) randomization into two groups of thirty each at 40 weeks. The Women were induced in the intervention group at 40 weeks with oxytocin or a single 24-hour application of a Foley catheter followed by oxytocin infusion and amniotomy. The expectant group underwent maternal and foetal surveillance and induction at 41 weeks with the same protocol if not delivered by then.
Data from all sixty women were analyzed. Twenty (66.67%) in the induction compared to ten (33.33%) in the expectant group delivered vaginally. This difference was significant (P = 0:016). One woman in the expectant group had scar dehiscence. In this pilot randomized controlled trial, authors found that in the uncomplicated pregnancies with a previous caesarean delivery, IOL at 40 completed weeks achieved significantly higher successful vaginal deliveries than planned expectant management till 41 weeks.
An RCT comparing IOL at 40 weeks with expectant management in women with previous caesarean sections is feasible and acceptable. Large population need to be screened for more extensive trials powered to detect any harm or difference in perinatal outcomes. Even with a small sample size of 30 in each arm, we found a significantly higher VBAC rate in the IOL group. Only 43% of those in expectant management underwent spontaneous labour.
“We recommend more extensive trials to study the safety and maternal and perinatal outcomes of induction at 40 weeks versus expectant management up to 41 weeks for women with singleton foetus with a previous caesarean scar who are eligible for TOLAC.”
Source: K. Rajalakshmi, Gowri Dorairajan, Swetha S. Kumar; Hindawi Journal of Pregnancy Volume 2023 https://doi.org/10.1155/2023/9189792
