Flaturia: passage of flatus at coitus. Incidence and pathogenesis

We present 18 women who under normal conditions had fecal and flatus control. They leaked flatus only during coitus. We investigated the hypothesis that these women had a concealed anal sphincteric disorder.

Eighteen multiparous women (mean age 44.8+/-7.2 SD years) complained of involuntary passage of flatus during coitus of 4.6+/-2.4 years duration. Mean deliveries amounted to 8.2+/-2.1, of which 5.2+/-1.1 were by forceps. Patients had neither fecal nor flatus incontinence except during coitus. Nine healthy volunteers matching patients in age and number of deliveries but without coital passage of flatus were included in the study. Monitoring comprised anorectal pressure studies and external and internal anal sphincter (EAS, IAS) electromyography (EMG). Plain X-ray and barium enema studies were done to detect stools in the rectum.

The rectal and anal pressures at rest and on voluntary squeeze of the patients matched those of the healthy volunteers. The recto-anal inhibitory reflex (RAIR) in the patients was abnormal; it recorded on rectal contraction a significantly lower anal pressure than that of the healthy volunteers; also, the rectal contraction occurred at a volume lower than with the volunteers. The EAS EMG of patients was normal, while their IAS EMG recorded a significantly lower activity at rest and on rectal distension than those of volunteers. Stools were detected at rest in the rectum of all patients and in only two of the volunteers.

The distal end of the erect penis seems to buffet the lower rectum at coitus. In patients, the abnormal RAIR, the diminished IAS EMG as well as the presence of stools in the rectum at rest appear to be responsible for passage of flatus at coitus.