Key takeaways

Nexplanon is a birth control implant that releases the hormone etonogestrel to prevent ovulation, thicken cervical mucus, and alter the uterine lining to prevent pregnancy for up to three years.
Common side effects of Nexplanon include headaches, weight gain, acne, irregular bleeding, and mood swings, while severe side effects can include seizures, strokes, and blood clots.
Menstrual changes are the most reported side effect of Nexplanon, with many women experiencing lighter periods, less cramping, and reduced PMS symptoms over time.
To minimize side effects, patients should provide a complete medical history to their healthcare provider, regularly check the implant’s placement, attend follow-up appointments, and be vigilant for signs of pregnancy or complications.

Nexplanon is a brand-name prescription women’s birth control implant that provides contraception for up to three years. Nexplanon slowly releases a progestin hormone, etonogestrel, to prevent monthly ovulation. The hormone also changes cervical mucus—making it harder for sperm to enter the uterus—and the uterine lining, making it more difficult for a fertilized egg to attach to the lining of the uterus.

Nexplanon is a single-hormone birth control treatment that does not contain estrogen. As with all hormonal birth control methods, Nexplanon can cause side effects and other problems. Before committing to a long-term implant, it helps to know possible side effects, precautions, and steps that can be taken to minimize problems.

RELATED: What is Nexplanon?

Common side effects of Nexplanon

The most common side effects of Nexplanon include:

Headache
Vaginitis
Weight gain
Acne
Irregular bleeding/breakthrough bleeding/no menses
Breast pain or tenderness
Abdominal pain
Sore throat
Vaginal discharge
Flu-like symptoms
Dizziness
Back pain
Mood swings
Nausea
Hypersensitivity reactions
Insertion site pain
Fluid retention
High cholesterol

Serious side effects of Nexplanon

Severe side effects of Nexplanon can include:

Seizures
Stroke
Heart attack
Blood clots
High blood pressure
Ovarian cysts
Ectopic pregnancy
Gallbladder disease
Severe allergic reactions

Nexplanon and menstrual bleeding

Menstrual changes are the most common side effect of Nexplanon. Many women with a Nexplanon implant will experience changes in their menstrual bleeding pattern, including changes in intensity and their menstrual cycle. The most common is spotting, but spotting typically improves in six to 12 months. For many women, however, Nexplanon usually makes periods lighter and, for some, eases both cramping and PMS.

Nexplanon and weight gain

In clinical studies, 13.7% of the women with a Nexplanon implant reported weight gain. The average weight gain was nearly three pounds one year after implant and close to four pounds two years after implant. While it is widely believed that hormonal birth control causes weight gain, scientists are not so sure. The cumulative evidence seems to suggest that it doesn’t, but some studies do show modest weight gain using contraceptive implants such as Nexplanon or Implanon.

Nexplanon and implant problems

Nexplanon implants are always inserted by a physician in a doctor’s office or clinic. Using a local anesthetic, a doctor inserts the implant just below the skin on the inside of the non-dominant upper arm. A number of Nexplanon problems are complications due to insertions, migration, or removal of the implant. In very rare cases, the implant is not inserted (about 0.01% of patients) or only partially inserted (0.37%), raising the risk of an unwanted pregnancy. When inserted too deeply (0.9% incidence), the implant could cause complications such as nerve or blood vessel damage. Other severe problems at the implant site are possible, such as severe pain, numbness, tingling, or altered arm movement, but these are rare (0.67% incidence).

Once inserted, an implant can come out by itself, break, bend, or migrate to other areas of the body. Some implants can get lost in the body and require X-rays and surgery to remove. Some have even been found in blood vessels. Other complications can occur during removal (1.3%).

Fortunately, severe complications are uncommon. More commonly, women could experience minor problems right after insertion or removal such as pain, bruising, rash, itching, infection, or scarring.

How long do side effects last?

If mild or moderate side effects are experienced, a healthcare provider will usually encourage the woman to keep the implant for another few months to see if side effects improve. If severe side effects are experienced or side effects are too unpleasant, the implant will be removed. Once removed, etonogestrel levels in the blood fall to undetectable levels in a week, so most temporary side effects such as headache, mood changes, and menstrual pattern changes will improve within a few days after removal. Serious side effects such as severe allergic reactions, blood clots, or an ectopic pregnancy will require emergency medical treatment. Some, such as severe blood clots or heart attack, could have lifelong complications.

Nexplanon contraindications & warnings

In addition to side effects, Nexplanon can cause other problems because of pre-existing conditions or other issues.

Abuse and dependence

Nexplanon does not cause physical dependence, so there are no withdrawal symptoms when the implant is removed. Nexplanon has no risk for drug abuse or misuse.

Overdose

An overdose of a progestin such as etonogestrel does not produce serious problems. Because Nexplanon is an implant, an overdose is highly unlikely. Bent or broken implants could release a slightly higher daily dose.

Restrictions

Contraindications are pre-existing conditions that make a prescription drug too unsafe to take. For anyone with certain pre-existing conditions, Nexplanon will not be inserted. These include:

Pregnancy (or suspected pregnancy)
Blood clot problems
Breast cancer or history of breast cancer
Progestin-dependent cancer or history of progestin-dependent cancer
Liver disease or liver tumors
Unexplained vaginal bleeding
Allergies to etonogestrel or any of the inactive ingredients in Nexplanon

Other pre-existing conditions may cause problems, but Nexplanon still can be used provided precautions are taken. However, although Nexplanon and other hormonal birth control options can be used in women with these conditions, having too many of these risk factors can be a contraindication. These include:

High blood pressure: Etonogestrel can raise blood pressure, so women with hypertension will need regular blood pressure monitoring after insertion.

High fat or cholesterol levels: Progestins can increase LDL levels, so women with a Nexplanon insert will need regular blood tests to ensure LDL is under control.

Diabetes: Etonogestrel may cause slight increases in blood sugar, so women with diabetes or prediabetes will need regular blood glucose monitoring.

Fluid retention: Birth control drugs usually cause some amount of fluid retention, so people with conditions that could be worsened by fluid retention require very careful monitoring.

Family history of breast cancer: Some breast cancers are sensitive to female hormones, that is, they depend on female hormones to grow. Women who have a family history of breast cancer are advised to be cautious about taking hormonal birth control.

Excess weight: Nexplanon has not been tested in women whose weight is 130% greater than ideal body weight. The implant may be less effective in women with excess body weight, raising the risk of unwanted pregnancy.

Depression: Women with depression or depressed mood will need to be monitored for any worsening of mood.

Heart problems and risk factors for blood clotting: Combination hormonal contraception can cause blood clots that could cause serious cardiovascular problems like heart attack and stroke. Progestin-only contraception may be less risky, but this is not certain. For this reason, Nexplanon is used cautiously in women with risk factors for blood clots, ischemic heart disease, or in the first six weeks after giving birth (if breastfeeding). Because of the risk for blood clots and heart attack, Nexplanon is never inserted into a woman in the first 21 days after giving birth.

Migraines: Women with a history of focal migraines are at a higher risk of stroke than other women. Healthcare professionals are cautious about using hormone birth control in women who have migraine with aura.

Smoking: Smoking raises the risk of blood clots and cardiovascular problems in women taking combination hormonal contraception, but the risk is unknown for single hormone medications like Nexplanon.

Pregnancy and nursing

Nexplanon is not used in pregnant women. A pregnancy test will be performed before the implant is inserted. The implant will be removed if pregnancy occurs during treatment.

Breastfeeding women can have a Nexplanon implant provided four weeks have passed since the baby’s birth. Etonogestrel is present in breast milk, but there is no evidence that it harms or affects a nursing infant. However, etonogestrel may reduce lactation. A healthcare professional may advise breastfeeding mothers to consider non-hormonal birth control as an alternative.

Children

The U.S. Food and Drug Administration (FDA) has approved Nexplanon for use in women of any age after menstruation has started. (However, clinical studies have not been performed in women under 18 years old.)

Seniors

Nexplanon is not used in women older than the age 65.

Nexplanon interactions

Other medications can cause problems in women with a Nexplanon implant. Prescription drugs, over-the-counter drugs, and supplements could make Nexplanon less effective or cause adverse effects. Most Nexplanon drug interactions, however, are minor.

Drugs that reduce the effectiveness of Nexplanon

Some drugs increase the speed with which the liver breaks down etonogestrel. Taking these drugs with Nexplanon will significantly reduce the effectiveness of Nexplanon as birth control. These include:

Barbiturates
Certain HIV drugs and Hepatitis C medications
Anticonvulsants such as phenytoin and carbamazepine
Dietary supplements such as St. John’s wort

Most of these drugs can be prescribed without removing the Nexplanon implant provided other contraception methods are used, as well. Women should also report any breakthrough bleeding or other side effects to a healthcare provider when taking these drugs.

Diabetes medications

Hormonal contraception may reduce the effectiveness of diabetes medications to control blood sugar. Diabetes medications may need their dosages changed.

How to avoid Nexplanon side effects

For most people, Nexplanon will cause few or minimal side effects. There are, however, practical ways to manage or minimize the side effects of an etonogestrel implant.

1. Tell the doctor about all medical conditions and medications

Some pre-existing conditions significantly raise the risk of side effects, so the doctor needs a complete medical history including medical conditions and all prescription drugs, over-the-counter drugs, and dietary supplements being taken. Make sure to tell the healthcare provider about:

Pregnancy
Blood clots
Liver disease or other liver problems
Breast cancer, history of breast cancer, or a family history of breast cancer
Unexplained vaginal bleeding
Diabetes
High cholesterol
High blood pressure
Migraines
Depression
Gallbladder problems
Kidney problems

A healthcare professional may decide Nexplanon is too risky and suggest an alternative form of contraception.

3. Continually check for the implant

The Nexplanon implant can be felt right beneath the skin. Once implanted, the doctor will let you feel the implant. If it is not palpable, it may not be there or it may be too deep. If it’s too deep, it could cause blood vessel and nerve problems. Regularly palpate the area to confirm the implant is still in place. If it can’t be felt, immediately contact a healthcare provider and start using alternative contraception methods.

4. Keep all follow-up appointments

Follow-up appointments with a healthcare provider are important to ensure the implant is working and not causing problems. Also, keep track of the implant’s removal date written on the user card given to every patient after implant insertion. Put the card in a safe place, but it’s also a good idea to have multiple reminders of the removal date.

5. Watch for signs of pregnancy

As with all birth control, women can still get pregnant on Nexplanon. If any signs of pregnancy are noticed, immediately call a healthcare provider. The implant will need to be removed immediately. There is a risk that the pregnancy could be an ectopic pregnancy, that is, the fertilized egg implants outside the womb, usually in a fallopian tube, or rarely in an ovary, or the cervix. An ectopic pregnancy is a potentially serious problem that will require immediate medical treatment.

6. Protect yourself from sexually transmitted infections

Nexplanon helps to prevent pregnancy but does not protect against sexually transmitted infections. If STIs are a possible risk, use barrier contraception.

Resources

Body composition and bone mineral density in users of the etonogestrel-releasing contraceptive implant, Gynecologic Endocrinology and Reproductive Medicine
Combination contraceptives: effects on weight, Cochrane Database of Systematic Reviews
Hormonal contraception—what kind, when, and for whom?, Deutsches Ärzteblatt International
Nexplanon, Epocrates
Nexplanon drug summary, Prescriber’s Digital Reference
Nexplanon prescribing information, U. S. National Library of Medicine