Comparing labour induction outcomes using misoprostol and dinoprostone in term pregnancies: A retrospective study at Kiambu Level 5 Hospital between 2018 and 2020

Abstract

Background: The Maternal and Perinatal Death Surveillance and Response (MPDSR) was introduced in Kenya in 2016 and implemented at Kiambu Level 5 Hospital (KL5H) three years later in 2019. During a routine MPDSR meeting at KL5H, committee members identified a possible link between the off-label use of 200mcg misoprostol tablets divided eight times to achieve the necessary dose for labour induction (25mcg) and maternal deaths. Following this, an administrative decision was made to switch from misoprostol to dinoprostone for the induction of labour in June of 2019. This study aimed to assess the overall impact of MPDSR as well as the effect of replacing misoprostol with dinoprostone on uterine rupture, maternal and neonatal deaths at KL5H.

Methods: We conducted a retrospective cohort study of women who gave birth at KL5H between January 2018 and December 2020. We defined the pre-intervention period as January 2018-June 2019, and the intervention period as July 2019-December 2020. We randomly selected the records of 411 mothers, 167 from the pre-intervention period and 208 from the intervention period, all of whom were induced. We used Bayes-Poisson Generalised Linear Models to fit the risk of uterine rupture, maternal and perinatal death. 12 semi-structured key person questionnaires was used to describe staff perspectives regarding the switch from misoprostol to dinoprostone. Inductive and deductive data analysis was done to capture the salient emerging themes.

Results: We reviewed 411 patient records and carried out 12 key informant interviews. Mothers induced with misoprostol (IRR = 3.89; CI = 0.21-71.6) had an increased risk of death while mothers were less likely to die if they were induced with dinoprostone (IRR = 0.23; CI = 0.01-7.12) or had uterine rupture (IRR = 0.56; CI = 0.02-18.2). The risk of dying during childbearing increased during Jul 2019-Dec 2020 (IRR = 5.43, CI = 0.68-43.2) when the MPDSR activities were strengthened. Induction of labour (IRR = 1.01; CI = 0.06-17.1) had no effect on the risk of dying from childbirth in our setting. The qualitative results exposed that maternity unit staff preferred dinoprostone to misoprostol as it was thought to be more effective (fewer failed inductions) and safer, regardless of being more expensive compared to misoprostol.

Conclusion: While the period immediately following the implementation of MPDSR at KL5H was associated with an increased risk of death, the switch to dinoprostone for labour induction was associated with a lower risk of maternal and perinatal death. The use of dinoprostone, however, was linked to an increased risk of uterine rupture, possibly attributed to reduced labour monitoring given that staff held the belief that it is inherently safer than misoprostol. Consequently, even though the changeover was warranted, further investigation is needed to determine the reasons behind the rise in maternal mortalities, even though the MPDSR framework appeared to have been put in place to quell such an increase.