Contraceptive Implant (Etonogestrel) in Taichung

What it is

The contraceptive implant is a small, soft rod placed under the skin of your upper arm. It slowly releases a progestogen hormone called etonogestrel. It is a long-acting reversible contraceptive (LARC).

It works in three ways. It stops the ovary from releasing an egg (ovulation). It makes the mucus at the neck of the womb (cervix) thicker. And it makes the lining of the womb (endometrium) less ready for a pregnancy to settle in.

The Taiwan product label states that it prevents pregnancy at least as well as combined oral contraceptive pills (over 99%). No contraceptive method works every time.

One rod is 4 cm long and 2 mm wide. It is placed under the skin on the inner side of the upper arm. This is done in the clinic with local anesthesia (numbing medicine). No internal (pelvic) examination is needed. Reactions at the insertion site happen in about 8.6% of users.

In Taiwan, the approved period of use is 3 years. The Taiwan label states that the same implant must not stay in place for more than 3 years. Some other countries have approved a longer period of 5 years. Taiwan has not. Our clinic follows the use approved in Taiwan, which is 3 years.

In Taiwan, the approved use is contraception only.

The label states that women using this product should be told it cannot prevent HIV/AIDS or other sexually transmitted infections.

Who should not use it

The Taiwan label lists seven situations in which this implant must not be used:

• Known or suspected pregnancy
• A history of an active blood clot in a vein (venous thrombosis)
• A known or suspected history of a cancer that is sensitive to sex hormones
• A history of a liver tumor, benign or malignant
• A history of severe liver disease, where liver function has not returned to normal values
• Vaginal bleeding that is not normal and has not been diagnosed
• Allergy to any ingredient of this product

Medicines that can lower the contraceptive effect

Some medicines speed up the way the body breaks down the hormone (enzyme inducers). They can make the implant less effective. Examples are rifampicin, several anti-epileptic medicines, St. John's wort, and efavirenz.

While you are taking such a medicine, and for 28 days after you stop it, you need to add a non-hormonal contraceptive method.

Bleeding changes: the main trade-off

In the first three to six months, your periods may become irregular, lighter, or stop completely.

According to the label, about one in five women have no periods at all (amenorrhea). Another one in five have bleeding that is frequent and/or lasts a long time. The rest bleed less often, or notice little change.

Having no periods does not mean that blood is trapped inside. It means the lining of the womb does not become thick while the progestogen is working.

In clinical trials, a change in the bleeding pattern was the most common reason for stopping the implant, at about 11%.

The Taiwan label states that most women can tell, from the bleeding pattern in the first three months of use, what their pattern will be later on. So the first three months are the ones to watch. Think about this before the implant is placed, not after.

How to book

The usual plan is one visit. Assessment, explanation, and insertion are done at the same appointment. After that, there is no routine follow-up visit.

Before insertion, we need to be sure that you are not pregnant. The doctor may arrange a pregnancy test, depending on the date of your last period.

The timing of insertion matters. If the implant is not placed within the recommended timing, you need to add a barrier method, such as condoms, for 7 days after insertion.

Whether it can be done on the same day is decided by the doctor at the visit.

When not to wait

There is no routine follow-up, but please come back without waiting if you have:

• Redness, heat, more pain, or discharge at the insertion site
• Numbness, tingling (pins and needles), burning, or weakness in that arm
• A missed period together with pain on one side of the lower belly (abdomen) — a pregnancy outside the womb, called ectopic pregnancy, must be ruled out
• Bleeding that does not stop, is heavy, or changes in a way that worries you
• You cannot feel the implant yourself, or it feels different from the day it was placed
• Fever

Checking the implant, and the 3-year visit

You can feel the implant under the skin at any time. If you cannot feel it, or you think it has moved, please come back so the doctor can check its position. Use another contraceptive method until the position is confirmed.

At 3 years you need a visit to have the implant removed or replaced. After that, the amount of hormone released falls, and the contraceptive effect can no longer be relied on. The implant is still inside your arm, so leaving it alone is not the same as stopping it.

This procedure is done with local anesthesia. You can travel home on your own afterwards. An adult companion is not needed.

To book, use our online booking system or our LINE official account. The clinic is at No. 98, Boguan 2nd Street, West District, Taichung.

Safety update, and what is known about cancer

Does the contraceptive implant placed under the skin cause cancer?

There are three separate things in this question. If we mix them together, the answer becomes misleading.

1. Tests for cancer-causing effects of the ingredient itself

The package insert (the official product information leaflet) records the safety data collected before the medicine was tested in people (preclinical data). In pharmacology and toxicology studies, etonogestrel did not show relevant carcinogenicity (cancer-causing effects) or genotoxicity (damage to genes). This is data from animals and from the laboratory. It can rule out worries of this type: "this ingredient is itself a substance that causes cancer". But we cannot turn it around and conclude that there is no risk in people.

2. The link with breast cancer: for now the answer is "the cause and effect cannot be confirmed yet"

The first item in the warnings of the package insert is breast cancer. It says that using combined oral contraceptives may slightly increase the risk of breast cancer, and that this risk gradually disappears within ten years after stopping. It then writes about methods that contain only progestogen (a hormone of the progesterone type): "With contraceptive methods that contain only progestogen, the level of risk is similar to that of combined contraceptives. However, the link between developing breast cancer and the use of contraceptive methods has not been fully proven. Seen against the risk of a woman developing breast cancer over her whole life, the link between breast cancer and the use of contraceptives is extremely low."

There is one place here that is easy to misread. The set of numbers by age group in the package insert (for example, 110 versus 100 per 10,000 people aged 30 to 34) comes from studies of combined oral contraceptives. It is not data from the implant itself. So the correct way to say it is this: there may be a link, the cause and effect is not yet established, and compared with the chance of developing breast cancer over a whole lifetime this link is small; but we also cannot say that there is no risk at all. In addition, the package insert lists a known or suspected history of a malignant tumour (a cancer) that is sensitive to sex hormones as one of the contraindications (situations in which the medicine must not be used).

3. September 2026: a new official safety message, about meningioma, not about cancer

According to the drug safety information risk communication table of September 2026 from the Food and Drug Administration in Taiwan: long-term use (more than 1 year) of contraceptive medicines containing desogestrel or etonogestrel may slightly increase the risk of meningioma (a tumour of the membranes around the brain), and the longer the medicine is used, the higher the risk. It is estimated that there is only 1 extra case for every 67,300 women who use the medicine. That document describes meningioma as "usually benign (non-cancerous), but depending on its size or its position it can still cause serious problems".

The same document also states that the Chinese-language package insert in Taiwan does not currently carry safety information about meningioma, and the Food and Drug Administration is evaluating whether to take further risk-control measures. The European committee for drug safety monitoring and risk assessment (the Pharmacovigilance Risk Assessment Committee) has recommended that women who have meningioma now, or who have had meningioma in the past, must not use these medicines.

What we actually do at the clinic

• Before the implant is placed, we check the contraindications listed in the package insert. These include a history of a malignant tumour (a cancer) that is sensitive to sex hormones, a history of benign or malignant liver tumours, and abnormal vaginal bleeding that has not been diagnosed.
• Because of the new information above, we also ask about any history of meningioma, and which progestogen (progesterone-type hormone) medicines you have used in the past.
• While you are using the implant, please see a doctor as soon as possible if you have changes in your vision, hearing loss or ringing in the ears, loss of smell, headaches that get worse, memory loss, seizures, or weakness in the arms or legs. Do not wait until the three years are over.
• A contraceptive method does not replace cervical cancer screening. Please have your smear test (Pap test) or HPV test according to the age-based advice you already follow.

If you have a history of breast cancer, a family history of breast cancer, or you are having follow-up for a breast lesion (a lump or abnormal area in the breast), whether this method is suitable for you must be assessed individually by a doctor. The information above is a starting point for the doctor's judgement. It is not a self-check list.

Sources: package insert search platform of the Food and Drug Administration, Ministry of Health and Welfare; Food and Drug Administration, September 2026, "Drug Safety Information Risk Communication Table for medicines containing desogestrel and etonogestrel".