NEW YORK (Reuters Health) – A new study of single- verus double-balloon catheters for labor induction suggests that both are equally effective, but hints at trends towards more adverse events and operative deliveries with the double-balloon catheter.
That, combined with the cost difference in the two methods, gave researchers confidence in using the single-balloon catheter at their institution.
Dr. Eliezer Shalev of the Emek Medical Center in Afula, Israel and colleagues randomized women assigned for cervical ripening to the single-balloon (Foley) or double-balloon catheter. All women were giving birth to a singleton with cephalic presentation. They had intact membranes with a Bishop score (range: 0-13) of 6 or less.
In total, 293 women were included in the final analysis: 145 in the single-balloon group and 148 assigned to the double-balloon catheter.
Median time from catheter insertion to delivery did not differ in the two groups (19.4 hrs for single-balloon, 19.1 hrs for double-balloon, P = 0.80); nor did cesarean section rate differ (10.3% for single-balloon, 17.6% for double-balloon, P = 0.09).
However, the incidence of either a cesarean or vacuum delivery was significantly lower in women who had the single-balloon catheter inserted (14.4% vs. 25.7% for double-balloon catheter, P = 0.02).
Dr. Shalev and colleagues also noted two women in the double-balloon group who had fetal malpresentation after catheter removal. One woman in that group needed an emergency c-section. Intrapartum fever developed in 5.4% of women with double-balloon catheters, versus 1.4% of women with single-balloon catheters (P = 0.10). Taken together, the incidence of adverse events was significantly lower in the single-balloon group (P = 0.02).
Previous studies have shown that cervical ripening using a balloon catheter is comparable in its effectiveness with pharmacological induction, but carries a lower risk of uterine tachysystole, the authors write in their Obstetrics & Gynecology report.
The researchers add that how much balloons are inflated may be important to outcomes. In this study, they inflated single-balloon catheters with 60 mL of saline and double-balloon catheters with 80 mL.
They also hypothesize that the traction created by the single-balloon catheter — creating stretching pressure on the lower uterine segment — may also be key to its effectiveness compared to the double-balloon catheter.
“In conclusion, the results suggest that either catheter is equally efficacious for inducing labor. However, the results also demonstrate some worrying trends toward increased adverse events and more operative deliveries with the double-balloon catheter,” Dr. Shalev and colleagues write.
“These findings, coupled with the fact that each double-balloon catheter costs our medical center $37 compared with $0.60 for the single-balloon catheter, make the single-balloon Foley catheter a more cost-effective method for labor induction.”
Obstet Gynecol, 2011.