Discussion
The goal of managing an antenatal woman with a scarred uterus is to provide the woman a well informed choice along with efficient and robust statistical data of the estimated risks associated with TOLAC and CS and also to make an individualised prediction of her estimated likelihood to have a successful VBAC if she wishes to opt for TOLAC. The most common indication of previous CS in the study population was foetal distress (25.8%) and the VBAC and CS rates were found to be similar for all indications of previous CS, comparable to study of Jozwiak et al9 where 30% population had previous CS done for foetal distress and the indication of previous CS did not affect the outcome of TOLAC.
The maximum inter-delivery interval observed in this study was 11 years and the minimum was 1.5 years (mean 4.63 years). Inter-delivery interval did not influence the outcome of TOLAC in the present study which was in sync with the results published by Sinha et al10, Patel et al11 and Gobillot et al12.
More women had VBAC compared to CS in the spontaneous labour group (84.2% vs 15.8%) whereas lesser women had VBAC compared to CS in the induced labour group (42% vs 58%). Sinha et al10demonstrated a similar CS rate of 48% in the induced group compared to the present study.
Mean cervical dilatation at admission was 1.9 cm and the mean cervical effacement at admission was 25.4%. The values of both were significantly higher in women who had VBAC (p=0.001). This was similar to the study by Landon et al1 where mean dilatation at admission was 3.3 cm which was significantly higher in VBAC group than CS group and patients who had dilatation >4 cm had 83.8% VBAC success.
The mean Bishop’s score at admission was 4.46 for the study population, 100% VBAC success was observed for patients with Bishop’s score >6 and patients with Bishop’s between 0-3 had only 39.5% VBAC rate. None of the previously done studies on outcomes following TOLAC assessed cervical effacement, station of vertex and Bishop’s score at admission as potential influencing variables for TOLAC success.
VBAC success rate of 42% was observed in induced women in the present study which was comparable to the results of Atia et al (39.8%)2
Out of the 69.3% induced women, most were induced for Preeclampsia (16.9%) followed by IUGR (14.9%) and ICP (12.9%). VBAC and CS rates were similar for all other indications except, ICP in which a significantly higher CS rate of 81.2% was observed as most of these women developed foetal distress or MSL intrapartum. Contrary to our study, maximum proportion of women had IOL for post-dated pregnancy in all other studies.2,3,12
The present study had caesarean section rate of 45.2% which was similar to the studies by Jozwiak et al9 and Goel et al13 but higher than that observed in the studies by Landon et al, Sinha et al and Patel et al.1,10,11Pathological CTG (21.8%) was the leading indication of CS in the present study which was in unison with the result of studies by Gobillot et al12 and Goel et al13 where most of the caesareans during TOLAC were done for foetal distress.
In the present study, the mean birthweight of the neonates born was 2.3 kg and it was similar among the VBAC and CS groups (2.78 vs 2.66 kg). Mean birthweight of the neonates had no influence on the outcome of TOLAC in our study and this was consistent with the results published by Atia et al and Patel et al.2,11
The mean Apgar scores at 1 min (7.79 vs 7.73) and 5 min (8.84 vs 8.79) were similar in neonates born by VBAC and CS in the present study which was consistent with the results of studies done by Atia et al and Shatz et al.2,3
In the present study, higher rate of neonatal complications were observed in the women who had failed TOLAC and underwent emergency repeat CS compared to those who had successful VBAC. Patel et al also observed similar results in their study cohort. 11
Only one neonatal death occurred during the study which was consistent with the low rates of neonatal mortality as observed in the study by Jozwiak et al9 (only 2 neonatal deaths).
Around 27.4% women in the study population had some complication (minor or major) during labour or in postpartum period. The complication rate was comparable among women who had VBAC and CS (29.4% vs 25%) in the present study. Patel et al and Gobillot et al also observed no significant difference in the complication rates among women who had VBAC and CS following TOLAC.11,12 Contrary to this, Shatz et al and observed increased rates of infection, PPH and blood transfusion in women who had failed TOLAC.3
No case of uterine rupture was observed in the study population despite a high IOL rate of 69.3%, however 5 out of 124 women did develop scar dehiscence. The most frequently occurring complication in the study cohort was PPH (8%) similar to the 12% rate of PPH observed by Jozwiak et al.9 The rate of occurrence of PPH was similar in VBAC and CS. Only one woman had massive PPH for which Bakri balloon was inserted and 5.6% women in the study cohort received blood transfusion. Around 4% women had cervical tear which is attributable to the 8% rate of forceps delivery in the study population. Only one woman developed vulvovaginal hematoma and one developed third degree perineal tear, consistent with the observations of Patel et al.11
Out of 124 women undergoing TOLAC, 37 (29.8%) accepted contraception. Around 12.9% women chose tubal ligation, 13.7% chose CuT 380 and 3.2% chose CuT 375 as the preferred contraceptive method. Contraception rate was significantly higher in women undergoing CS than in women who had VBAC (41% vs 20.5%) which reflects the likely ease of getting ligation done during the surgical procedure of CS itself. None of the previously published studies have evaluated the contraceptive choice of women following TOLAC.