Vaccum -assisted deliveries are at highest odds for injury to anal sphincter

Women who undergo Ventouse, also known as vacuum-assisted vaginal delivery or vacuum  extraction (VE) to cut short the second stage of labor are at 4 times the odds of obstetric anal sphincter injuries (OASIS) as compared to spontaneous vaginal delivery reports the results of retrospective cohort study published in February issue of Obstetrics and Gynecology.

It is estimated that about 1 in 10 primiparas will develop some degree of anal incontinence after vaginal delivery, which improves as months' progress.  Despite it, the matter is rarely talked about because of shame and taboo associated with it.

OASIS results in considerable comorbidities later in life including urgency, fecal incontinence, sexual dysfunctions, rectovaginal fistula and chronic pain. Hence, an awareness regarding the risk factors is necessary among health care provider to avoid the primary event.

This single-center study carried out at Kaiser Permanente Northern California looked at delivery data of about 22,741 women over a period of 2 years. All these women had undergone term, singleton delivery with the fetus in cephalic presentation. The study mainly focused on the incidence of third and fourth degree perineal tear as per World Health Organization classification.

After statistical analysis, it was seen that about 5% of women suffered OASIS, with the rate being minimum with spontaneous delivery (3.6%) and highest (24%) in vacuum-assisted vaginal delivery (P<.001).

After accounting for confounders, the other risk factors identified for OASIS were nulliparity, Asian ethnicity, second stage more than 2 hours, vaginal birth after cesarean delivery (VBAC), episiotomy, and vacuum delivery.

Women with vacuum extraction had the highest odds (4 times) of OASIS, followed by women who had labored for more than 3 hours in the second stage of labor (3 times) vs 1 hour.

The authors concluded that vacuum extraction and prolonged second stage of labor were the two risk factors that put the women at highest odds of OASIS.

Abstract

Media courtesy: American Society of Colon and Rectal Surgeons