Which of the following contraceptive methods requires a doctor's intervention for acquisition?

The contraceptive implant is a method that involves a healthcare professional for its insertion and removal. This implant is a small rod placed under the skin of the upper arm, which releases hormones to prevent ovulation and is effective for several years. Because the procedure requires medical training to ensure proper placement and to monitor any potential side effects or complications, it needs a doctor's intervention.

In contrast, male condoms, diaphragms, and periodic abstinence can all be practiced or obtained without direct involvement from a healthcare provider. Male condoms can be purchased over-the-counter at many retailers, and diaphragms, while requiring a fitting by a healthcare provider initially, can be used without ongoing medical supervision. Periodic abstinence is a behavior-based method not requiring any specific medical intervention. Thus, the need for a doctor's involvement makes the contraceptive implant the correct choice in this scenario.