Nexplanon is a highly effective, long-acting reversible contraceptive (LARC) device inserted under the skin of the upper arm. The implant continuously releases a low dose of the progestin hormone etonogestrel, which prevents pregnancy primarily by stopping ovulation and thickening cervical mucus. The most common side effect experienced by users is a change in the normal menstrual bleeding pattern. This alteration in bleeding is the primary reason why about one in ten women choose to have the implant removed early.
The Initial Post-Insertion Period
Immediately following the procedure, some bleeding is common, usually resulting from the insertion process itself rather than hormonal changes. The area where the implant was placed may experience minor trauma, leading to slight bruising or spotting from the insertion site. This localized bleeding is typically minimal and resolves quickly, within the first few days, as the small wound heals.
The initial introduction of the etonogestrel hormone into your system can also trigger light bleeding or spotting from the uterus in the days or weeks following insertion. This is often characterized as light, intermittent spotting, which can be managed with panty liners. While this type of spotting is a common early side effect, heavy menstrual-like bleeding immediately after insertion is not the typical experience. If bleeding becomes heavy right away, it is important to monitor it closely.
The first few weeks serve as an early adjustment phase for the body as it begins to respond to the continuous, low-level progestin. Most people will find that any immediate spotting related to the procedure or the initial hormonal shift subsides within the first week or two. However, this early period is distinct from the long-term changes that will develop as the body adjusts over the coming months.
Understanding Long-Term Changes to Your Cycle
The most significant and lasting changes to your bleeding pattern begin to establish themselves over the first three to six months as your body acclimates to the implant’s steady hormone release. The progestin works by stabilizing the uterine lining, but without the cyclical hormone fluctuations of a natural cycle, the lining can shed irregularly. This mechanism results in the unpredictable bleeding patterns that are characteristic of Nexplanon use.
There are three main patterns users may experience over the long term. The most common pattern is irregular spotting, or breakthrough bleeding, which involves frequent but light bleeding that can occur unpredictably throughout the month. For some, this irregular bleeding can be prolonged, lasting for many days at a time.
Another significant group of users will experience amenorrhea, the complete cessation of menstrual bleeding or spotting. Studies show that about one in five women using the implant will stop getting a period entirely. Conversely, a smaller portion of users may settle into a pattern of frequent or prolonged heavy bleeding episodes. A predictable monthly period is not expected while the implant is in place.
When Bleeding Requires Medical Attention
While changes in bleeding are common with the implant, certain signs should prompt immediate contact with a healthcare provider. Bleeding that is excessively heavy is a cause for concern, specifically if you are soaking through more than one standard sanitary pad or tampon per hour for several consecutive hours. This level of blood loss can quickly lead to anemia and requires professional evaluation.
You should also seek medical attention if heavy bleeding is accompanied by severe abdominal or pelvic pain, which could signal a serious issue like an ectopic pregnancy. Other red flags include:
- Signs of infection at the insertion site, such as pus, increasing pain, or a fever.
- Symptoms of anemia, such as extreme fatigue, dizziness, or shortness of breath.
- If you are unable to feel the implant under your skin, or if you suspect it has moved, as this could reduce its effectiveness.