Antepartum pudendal neuropathy and the effect of vaginal delivery in women with type 1 diabetes mellitus in pregnancy

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 )