WASHINGTON – Adding to women’s options for birth control, federal drug regulators announced approval Tuesday of a long-acting contraceptive implanted in the upper arm.

The new drug, Implanon, is a matchstick-size rod that steadily releases a small amount of the hormone progestin preventing pregnancy. Tests in women found it 99 percent effective.

Doctors place Implanon just under the skin with a local anesthetic and can remove it at any time. Once it is removed, a woman could regain the fertility necessary to become pregnant within as little as a month, a federal regulator said.

The new drug will be the first implanted in the arm to be marketed in the United States since sales of Norplant were halted in 2000 amid concerns about its effectiveness and serious side effects, like excessive bleeding and headaches. Other problems with Norplant arose because insertions and removals were performed by untrained doctors.

Dr. Scott Monroe, who heads the Food and Drug Administration’s reproductive drugs office, expressed confidence that Implanon won’t encounter the troubles that beset Norplant.

“Some of the issues related to Norplant, which were related to insertion and removal, will be much less of a concern with Implanon because it will involve a single rod,” he said.