Cesarean may not avert levator ani injury.(Obstetrics)

TUCSON, ARIZ. -- One woman in four suffers neuropathic injury to the levator ani with her first delivery, according to a novel study that used pre- and postpartum concentric needle electromyographic examinations to study muscle function.

Cesarean sections performed during labor were not protective in the study conducted by Dr. Alison C. Weidner and her associates at Duke University Medical Center and presented at the annual meeting of the Society of Gynecologic Surgeons.

Initial EMG studies were performed on 58 primiparous women in the early third trimester, providing baseline data on muscle function at four separate sites of the levator ani. A quantitative amplitude analysis provided data on muscle function at rest and during moderate and maximum voluntary contractions.

Information was collected on the subjects' labor and delivery patterns, and follow-up examinations were performed 6 weeks and 6 months post partum.

The mean age of the subjects was 29 years, and their mean body mass index was 25 kg/[m.sup.2].

Evidence of neuropathic injury was seen in 14 (24%) of 58 subjects at the 6 week examination and 17 (29%) of 58 at the 6-month examination, said Dr. Weidner, chief of the division of urogynecology at the Durham, N.C., institution.

Some women who demonstrated neuropathic injury at 6 weeks were normal by 6 months, while a few who seemed normal at 6 weeks showed evidence of injury at 6 months.