Obstetric anal sphincter injuries among women with gestational diabetes and women without gestational diabetes: A NSW population‐based cohort study

Abstract

Background: Obstetric anal sphincter injuries (OASIs) are associated with maternal morbidity, however it is uncertain whether Gestational Diabetes (GDM) is an independent risk factor when considering birth weight, mode of birth and episiotomy. Aims: To compare rates of OASIs between women with gestational diabetes (GDM) and women without GDM by mode of birth and birthweight. To investigate the association between episiotomy, mode of birth and the risk of OASIs. Methods: A population-based cohort study of women who gave birth vaginally in NSW, from 2007 to 2013. Rates of OASIs were compared between women with and without GDM, stratified by mode of birth, birthweight and a multi-categorical variable of mode of birth and episiotomy. Adjusted Odds Ratios (AOR) and 95% Confidence interval (CI) were calculated by multivariable logistic regression. Results: The rate of OASIs was 3.6% (95% CI 2.6-2.7) versus 2.6% (95% CI 3.4-2.8) (p<0.001) among women with and without GDM, respectively. Women with GDM and a macrosomic baby (birthweight ≥4000g), had a higher risk of OASIs with forceps (AOR 1.76, 95% CI (1.08-2.86), p=0.02) or vacuum (AOR 1.89, 95% CI (1.17-3.04), p=0.01), compared with those without GDM. For primiparous women with GDM and all women without GDM, an episiotomy with forceps was associated with lower odds of OASIs than forceps only (primiparous GDM, forceps-episiotomy AOR 2.49, 95% CI (2.00-3.11), forceps AOR 5.30, 95% CI (3.72-7.54)), (primiparous without GDM, forceps-episiotomy AOR 2.71, 95% CI (2.55-2.89), forceps AOR 5.95, 95% CI (5.41-6.55)) and (Multiparous without GDM, forceps-episiotomy AOR 3.75, 95% CI (3.12-4.50), forceps AOR 6.20, 95% CI (4.96-7.74)). Conclusion: Women with GDM and a macrosomic baby should be counselled about the increased risk of OASIs with both vacuum and forceps. With forceps birth this risk can be partially mitigated by performing a concomitant episiotomy. Short Communications Women with GDM and a macrosomic baby should be counselled about the increased risk of OASIs with instrumental birth. For forceps births this risk can be reduced by performing an episiotomy.

Virtual issue on diabetes in pregnancy

“…Zeki's study looks at the important problem of obstetric anal sphincter injury and its association with birth mode with or without episiotomy for women with gestational diabetes. 22 Another study reports an increasing trend to early-term labour induction for women with GDM with associated high rates of neonatal unit admission but good short-term newborn health. 23 Concerning intrapartum caesarean section, maternal diabetes and late pregnancy biometry were associated with intrapartum caesarean section as determined by retrospective modelling but whether this will be useful prospectively remains to be seen.…”

“…Readers focusing on birth mode and timing for women with diabetes in pregnancy will find several papers of interest in this edition. Zeki's study looks at the important problem of obstetric anal sphincter injury and its association with birth mode with or without episiotomy for women with gestational diabetes . Another study reports an increasing trend to early‐term labour induction for women with GDM with associated high rates of neonatal unit admission but good short‐term newborn health .…”