Diabetes Mellitus and lower genital tract tears after vaginal birth : a cohort study

Introduction: Diabetes Mellitus in pregnancy is increasing. No existing studies have examined Diabetes Mellitus as the primary exposure for lower genital tract tears after vaginal birth. The objective was to study the association between Diabetes Mellitus (all types combined), Type 1 Diabetes Mellitus, Type 2 Diabetes Mellitus and Gestational Diabetes Mellitus and lower genital tract tears after vaginal birth. Material and methods: A register-based cohort study of women with singleton pregnancy and without a previous cesarean section at near-term (≥ 35 + 0 weeks) and term (≥ 37 + 0 weeks) gestational age, n = 31,297 at Aarhus University Hospital, Denmark from 1 January 2004 to 31 December 2012. The associations between Diabetes Mellitus and lower genital tract tears were analysed using a fixed multiple logistic regression analyses. Results: Approximately 32,000 women were eligible for the study; 796 women had diabetes (2.5%) and 1318 experienced anal sphincter injury (4.3%). The overall risk of lower genital tract tears was similar among women with a diagnosis of diabetes (Type1 Diabetes Mellitus, Type 2 Diabetes Mellitus, and Gestational Diabetes Mellitus) compared to women without diabetes, except for nulliparous women with Type1 Diabetes Mellitus who experienced a higher risk of episiotomies, crude and adjusted odds ratios (OR 2.13, 95% CI 1.14-3.97) and (OR 2.48, 95% CI 1.21-5.10), respectively. Conclusions: Women with Diabetes Mellitus without a previous cesarean section who gave birth vaginally to a single child at term or near term did not experienced an increased risk of lower genital tract tears. However, nulliparous women with Type 1 Diabetes Mellitus experienced a higher risk of episiotomy. These results may be used to individualised counselling of women with Diabetes Mellitus regarding mode of birth and may reduce worries about genital tract tears in women with Diabetes Mellitus considering vaginal birth.