Comparison of rigid and flexible cannulae for early abortion without cervical dilatation. World Health Organization Task Force on Sequelae of Abortion.
A randomized controlled trial comparing four types of cannula for early abortion was undertaken in seven World Health Organization Collaborating Centers for Clinical Research in Human Reproduction. One-holed and two-holed cannulae, both flexible and rigid, were used to perform early abortions less than 46 days after the last menstrual period. A total of 3,066 women participated in the study. The adjusted incidence rates of failed abortion (0.95 to 6.4 percent) and of postprocedure bleeding requiring recurettage (8.8 to 9.1 percent) in the one-holed cannula group were significantly higher than the rates in the three other cannulae groups (3.0 to 3.5 and 2.2 to 3.8 percent, respectively). The rates for continuation of pregnancy were higher than those reported by other investigators, possibly owing in part to successful follow-up and the use of routine pregnancy testing at the follow-up visit.
D000028:Abortion, Induced / Q000009:adverse effects / Q000295:instrumentation*; D002404:Catheterization / Q000295:instrumentation; D002986:Clinical Trials as Topic; D004107:Dilatation and Curettage / Q000295:instrumentation*; D004209:Disposable Equipment; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D006801:Humans; D011247:Pregnancy; D011897:Random Allocation; D014619:Vacuum Curettage / Q000009:adverse effects / Q000295:instrumentation*; D014944:World Health Organization