Do routinely measured delivery variables predict anal sphincter outcome?

PURPOSE: Trauma to the anal sphincter is a recognized complication of primi parous childbirth. This damage may be compounded during subsequent deliveri es leading to symptoms. Earlier work is inconclusive as to which delivery v ariables are associated with such damage and may prove useful in predicting its occurrence, thereby allowing the potential for intervention in these l ater deliveries to protect the traumatized anal sphincter. The purpose of t he present study was to determine whether routinely recorded obstetric vari ables can be correlated to anal sphincter damage in a consecutive series of females. METHODS: A prospective study was undertaken in a single maternity unit. Patients delivering were assessed before discharge using a symptom q uestionnaire and endoanal ultrasound. Delivery data were collected prospect ively and analyzed statistically to see if a significant difference existed in the presence of an anal sphincter defect. RESULTS: A total of 159 patie nts were assessed. Endosonography revealed sphincter injuries in 8.7 percen t of the normal vaginal delivery group and 83 percent of the forceps delive ry group. No correlation was found between head circumference, baby weight, maternal body mass index, epidurals, episiotomy, length of each stage of l abor, and duration of active pushing. Forceps delivery was the only factor to be significantly associated with sphincter trauma. CONCLUSION: Besides f orceps delivery, commonly measured delivery variables are not useful predic tors of anal sphincter trauma. Normal vaginal deliveries do not warrant rou tine postnatal anorectal assessment, but this should be routine for all ins trument deliveries.