Int J Diabetes & Metabolism (2006) 14: 82-86 82 Antepartum pudendal neuropathy and the effect of vaginal delivery in women with type 1 diabetes mellitus in pregnancy Rhona Mahony 1 , Conor O’ Brien 1 , Brendan Kinsley 2 , Richard Firth 2 , Mary Coffey 3 , Ronan O’Connell 4 Colm O‘Herlihy 1 Department of Obstetrics and Gynaecology, University College Dublin, National Maternity Hospital, Dublin. 1 Department of Medicine, University College Dublin,Mater Misericordiae Hospital, Dublin, 2 National Maternity Hospital 3 , Department of Surgery, University College Dublin,Mater Misericordiae Hospital,Dublin 4 ____________________________________________________________________________________________________ Abstract Vaginal delivery is associated with a significant risk of pelvic floor neuropathy and anal sphincter dysfunction. Because insulin-dependent diabetes mellitus (IDDM) predisposes to neuropathy, our aim was to determine the incidence of pudendal nerve dysfunction in a cohort of pregnant insulin-dependent diabetic patients and to examine the effect of vaginal delivery on pudendal nerve and anal sphincter function. Materials and Methods: The pudendal nerve was evaluated using electromyography of the anal sphincter (EMG) and clitoral anal reflex (CAR) assessment, during the third trimester in 16 pregnant insulin-dependent diabetic women. Upper limb neurological assessment included median motor, ulnar f-wave, median and ulnar sensory nerve and median transpalmar nerve conduction studies, while the lower limbs were assessed using tibial motor and f-wave studies. Anal manometry and endoanal ultrasound studies were also performed. Thirteen women underwent full reassessment at three months postpartum. Results: An increased sensory threshold (>9mA) on CAR was demonstrable antenatally in 5 women on the right and 8 on the left. Seven women showed prolonged distal latency (>42ms) on the right and in 8 on the left. Five women showed prolongation of median transpalmar nerve conduction studies (>2.2ms), which was associated with diabetes of greater than 12 years duration (p=0.029). The median squeeze pressure was 129mmHg and median resting pressure was 62mmHg. There were no significant changes in nerve conduction or anal manometric pressures postnatally. Discussion: Pregnant women with type 1 IDDM exhibit subtle changes of axonal neuropathy and demyelination, but we found no increased susceptibility to pudendal nerve injury during vaginal childbirth. (Int J Diabetes Metab 14: 82-86, 2006 ) Key Words: Childbirth, Insulin dependent diabetes, pudendal nerve, Introduction In the general population, faecal incontinence occurs with a female to male preponderance of 8:1, consistent with pelvic floor injury following childbirth as the primary causative factor. 1,2,3 Up to 25% of women experience some alteration in faecal continence postpartum and up to one third have ultrasound evidence of anal sphincter trauma following apparently uncomplicated vaginal delivery. 1,2 The aetiology of faecal incontinence following vaginal delivery reflects either direct anal sphincter disruption or pudendal nerve injury or a combination of both. The anatomy of the pudendal nerve renders it particularly susceptible to traction and compression injuries within the pelvis. 4,5,6 Diabetes mellitus is the most common cause of polyneuropathy in the developed countries, 7 often manifesting as a distal symmetric sensory polyneuropathy, although almost any form of neuropathy can occur. Pregnant women not uncommonly experience neuropathies which may be focal or multiple and specific to gestation, the primary example of which is carpal tunnel syndrome secondary to median nerve compression. 8-10 Because diabetes is associated with increased susceptibility to both focal and polyneuropathy, it was our hypothesis that ____________________________________ Received on: 22/2/06 Accepted on: 11/9/06 Correspondence to: Rhona Mahony, Department of Obstetrics and Gynaecology, University College Dublin,National Maternity Hospital, Dublin 2, Tel: 353 1 6610277, Email: rhonamahony@hotmail.com the pudendal nerve might be more susceptible to injury in pregnant diabetic women during vaginal childbirth. The aim of this study was to determine the susceptibility of the pudendal nerve to injury during vaginal childbirth in a cohort of pregnant insulin-dependent women. Materials and Methods Sixteen pregnant women with type 1 IDDM (9 primigravid and 7 multigravid) were recruited from the dedicated diabetic antenatal outpatient clinic of the National Maternity Hospital and were assessed during the third trimester of pregnancy. Women with a history of anorectal disease, previous third degree tear or anorectal surgery and irritable bowel syndrome were excluded from the study. Antenatal continence assessment consisted of a structured bowel function questionnaire modified from Jorge and Wexner. 11 This score was based on the presence of flatal, liquid and solid faecal incontinence and included faecal urgency as this is a common and debilitating symptom. A score of 0 implies complete continence while a score of 20 implies complete incontinence. Anal sphincter function was assessed using anal manometry and endoanal ultrasound. Neurophysiological screening for polyneuropathy consisted of upper and lower limb motor and sensory nerve conduction studies. The pudendal nerve was assessed using clitoral anal reflex (CAR) and surface electromyography (EMG) of the anal sphincter. 6 Postnatally patients were assessed at 3 months postpartum, at which time the antenatal neurophysiological and anal physiological investigations were repeated and compared to antepartum values.