Interpretation
So far, in many studies, while discussing the effect of vaginal misoprostol use on ToP in patients with a history of C/S, the second trimester was mostly considered as reference and different gestational weeks were taken as the limit.3, 6, 7, 10, 12 Since the association of increased doses of misoprostol with increased risk of complications in termination of pregnancy is known, so our study offers the opportunity to compare the efficacy of misoprostol at low doses in all patients below 34 weeks of gestation and its relation with history of C/S. Accordingly, when patients with a history of C/S below 24 weeks of gestation (G2) and above (G4) were compared among themselves, as the total misoprostol dose (673,8 ± 457,3 µg vs 443,5 ±212,8 µg) descreased, the duration of treatment (19,4 ±15,9 hours vs 25,3 ±12,6 hours) and induction to labor interval (23,5 ±14,2 hours vs 31,5 ±19,9 hours) increased and the difference between them was found significant. It has been reported in many studies that the induction-labor time shortens as the vaginal misoprostol dose is increased, but it is noteworthy that the misprostol dose used in these studies is higher than the regimens in the current study.8, 10
In the present study, although the need for transfusion (0,9% vs 2,2%) increased as the gestational week progressed among patients with prior C/S history below and above 24 weeks of gestation, the difference was found not significant. In addition, admission to MICU (0,9% vs 0%) rates were very low and similar between the two groups. In other words, a decrease in the dose of misoprostol used does not cause a significant change in comorbidities, although it prolongs the induction-labor time. In a systematic review by Berghella et al discussed that the results of patients with a prior history of C/S between 16 and 28 weeks of gestation who underwent pregnancy termination with misoprostol.3 In this review, the need for transfusion was found 0,2%, but the weeks of gestation, administration route and dose of misoprostol of the patients included in the review were highly variable.
One of the major disadvantages of LD vaginal misoprostol therapy in ToP cases is the need for an auxillary treatment if the current protocol fails. The need for an auxillary treatment increases the risk of treatment non-compliance by prolonging the period until delivery and causing some psychological side effects for the patient.2, 11 In the present study, >1 ToP procedure was required in 14% of patients between 24-34 weeks of gestation and 5,8% of patients under <24 weeks of gestation. In other words, when the entire patient group was considered, regardless of the history of cesarean section, the highest success with the single ToP method was found in the Gx (G1-2) group, which results were similar to previous studies.3, 8, 13 The group in which more than one ToP procedure is needed the least (3,7%) is the patients (G1) without a history of cesarean section at <24 weeks of gestation. Accordingly, in the presence of a progress with gestational week or a history of cesarean delivery, LD vaginal misoprostol administration may result in unsuccessful results, increasing the need for an auxillary treatment. However, there was no evidence of increased complications (uterine rupture or atony) when all groups were compared among themselves. To date, the highest uterine rupture rate reported in the literature is 11,5%, and in this study, unlikely a minimum of 1200 µg misoprostol was administered in patients with a history of two or more C/S (14-26 weeks).12 In the systematic review presented by Berghella et al, uterine rupture rate was reported 0,43% in one prior history of C/S, but the doses used were highly variable.3 In the current study, uterine rupture was observed only in 3 cases (0,8%) below 24 weeks of gestation, and uterine atony was observed in 2 cases (0,9%) above 24 weeks of gestation. We think that the low complication rate in our study is related to the misoprostol dose and dose range administered.