This integrated analysis evaluates nonmenstrual adverse events, blood pressure, and body weight changes during the use of the single-rod etonogestrel-containing contraceptive implant, Implanon(R); these aspects are compared for Implanon and Norplant(R), the six-capsule implant containing levonorgestrel. Overall, 47% of Implanon users had drug-related adverse events, whereas in the comparative studies the figure for those using Implanon (61%) was slightly lower than that for Norplant users (69%). In all Implanon studies, 22 of 1716 women (0.7%) were affected by serious adverse events that were considered drug related. in comparative studies three of the 689 Implanon users (0.4%) and one of 689 Norplant users (0.1 %) had such experiences. The most frequently reported drug-related adverse events were acne, breast pain, headache, and weight gain. The adverse events that most often caused discontinuation of Implanon were weight gain and acne. The development or aggravation of acne was a frequent adverse event (in 18.5% of Implanon and 22.3% of Norplant users in the comparative studies) but individual studies indicated that there were also many subjects whose acne improved during implant use. There were gradual increases in body weight over time but these may be only partly attributable to implant use and partly attributable to normal increases over time. (C) 1998 Elsevier Science inc. All rights reserved.