What are the downsides of Nexplanon?

October 7, 2025 •

4 min read

In clinical trials, a change in menstrual bleeding patterns was the most common side effect of Nexplanon, leading about 1 in 10 women to discontinue its use [1.3.3, 1.8.1]. While highly effective, it's important to understand what are the downsides of Nexplanon before choosing this contraceptive method.

Quick Summary

An in-depth look at the potential negative effects of the Nexplanon birth control implant. This covers common side effects like irregular bleeding and mood swings, alongside rarer, more serious risks such as blood clots and implant migration.

Key Points

Irregular Bleeding: The most common side effect is a change in menstrual patterns, including irregular, prolonged, or absent bleeding, which leads many to discontinue use [1.3.3, 1.4.1].
Common Adverse Effects: Headaches, weight gain, acne, breast pain, and mood swings (including depression) are frequently reported by users [1.5.1, 1.8.1].
Serious Vascular Risks: Nexplanon increases the risk of serious blood clots, which can lead to stroke, heart attack, or pulmonary embolism, especially in smokers [1.11.1].
Procedural Complications: Insertion or removal can lead to pain, bruising, infection, scarring, or nerve/vessel injury. The implant can also be difficult to remove if it migrates [1.4.2, 1.10.1].
Ectopic Pregnancy Risk: While pregnancy on Nexplanon is rare, if it does occur, there is a higher chance of it being an ectopic pregnancy, a medical emergency [1.11.2].
Contraindications: Nexplanon is not suitable for individuals with a history of blood clots, certain cancers (like breast cancer), liver disease, or unexplained vaginal bleeding [1.4.2].
Weight Gain: In clinical trials, 13.7% of women reported weight gain, with an average increase of about 3-4 pounds after 1 to 2 years [1.5.1, 1.7.4].

Understanding Nexplanon and Its Function

Nexplanon is a long-acting, reversible contraceptive implant that is placed discreetly under the skin of the upper arm [1.7.3]. It is a small, flexible plastic rod that releases a progestin hormone called etonogestrel [1.9.1]. This hormone primarily works by preventing ovulation (the release of an egg from the ovary), thickening cervical mucus to prevent sperm from reaching an egg, and changing the lining of the uterus [1.8.1]. It provides continuous contraception for up to three years and is over 99% effective, making it one of the most reliable birth control methods available [1.3.3, 1.8.3]. Despite its effectiveness and convenience, potential users should be aware of its associated downsides and side effects.

Common Side Effects and Downsides

The most frequently reported downside of Nexplanon is a change in menstrual bleeding patterns [1.4.1]. These changes can vary significantly among individuals.

Menstrual Irregularities

Clinical studies show that changes in bleeding are the most common reason for discontinuing the implant, with 11.1% of women stopping use for this reason [1.3.2, 1.5.1]. Users may experience:

Irregular Bleeding and Spotting: This is the most common complaint [1.4.5].
Changes in Frequency: Periods may become more or less frequent [1.2.5]. Some women (about 1 in 5) may stop having periods altogether (amenorrhea), while others may experience frequent or prolonged bleeding [1.4.5].
Changes in Intensity: Bleeding may become heavier or lighter [1.2.5].

Other Common Adverse Reactions

According to clinical trials, other common side effects reported by at least 5% of users include [1.5.1]:

Headache: Reported by 24.9% of users.
Vaginitis (inflammation of the vagina): 14.5% of users.
Weight Gain: 13.7% of users reported weight gain, with an average gain of 2.8 pounds after one year and 3.7 pounds after two years [1.7.1, 1.7.4]. However, some studies suggest there is no significant difference in weight gain compared to non-users [1.9.1].
Acne: Affecting 13.5% of users. Some with pre-existing acne report improvement, while others see it worsen [1.7.3].
Breast Pain: Reported by 12.8% of users.
Abdominal Pain: 10.9% of users.
Mood Swings, Emotional Lability, and Depression: Mood swings and depressed mood are among the other frequent side effects that cause women to stop using the implant [1.8.1]. In studies, emotional lability was reported by 6.5% of users and depression by 5.5% [1.5.1].

Serious Risks and Complications

While less common, Nexplanon is associated with several serious risks that require immediate medical attention.

Blood Clots

Nexplanon may increase the risk of serious blood clots (thrombosis), which can occur in the legs, lungs, brain, or heart, potentially leading to a stroke or heart attack [1.11.1, 1.11.2]. This risk is higher in women who smoke or have other risk factors for blood clots [1.11.1].

Issues with Insertion and Removal

Complications can occur during the insertion and removal procedures, which must be performed by a trained healthcare professional [1.4.2].

Incorrect Insertion: The implant could be inserted too deeply, potentially causing nerve or blood vessel injury [1.3.4]. In rare cases, a failed insertion may go unrecognized, leading to a risk of unintended pregnancy [1.10.1].
Migration: The implant can move from its original location. There are rare reports of implants migrating to the pulmonary artery (a blood vessel in the lung), which may require surgical removal [1.4.2, 1.10.2].
Difficult Removal: If the implant cannot be felt, has migrated, or is encased in fibrous tissue, removal can be difficult or even impossible without special procedures [1.4.2].
Local Site Reactions: Pain, bruising, swelling, infection, or scarring can occur at the insertion site [1.3.5].

Ectopic Pregnancy

If pregnancy occurs while using Nexplanon, there is a slightly higher chance that it will be an ectopic pregnancy (occurring outside the uterus) [1.11.2]. This is a medical emergency that can cause severe internal bleeding and requires immediate medical attention [1.4.1].

Other Potential Risks

Ovarian Cysts: Cysts may develop on the ovaries. They often disappear without treatment, but sometimes surgery is necessary [1.4.1].
Liver Disease: Do not use Nexplanon if you have liver disease or a liver tumor [1.4.2].
High Blood Pressure: The implant can cause an increase in blood pressure [1.7.1].
Gallbladder Problems: Some hormonal contraceptives have been linked to gallbladder issues [1.11.1].

Contraindications: Who Should Avoid Nexplanon?

Nexplanon is not suitable for everyone. It should not be used by women who [1.4.2, 1.4.4]:

Are pregnant or suspect they might be.
Have a current or past history of blood clots.
Have liver disease or liver tumors.
Have unexplained abnormal genital bleeding.
Have or have had breast cancer or another progestin-sensitive cancer.
Have an allergic reaction to any of the components in Nexplanon.

Side Effect Comparison: Nexplanon vs. Other Methods


Feature/Side Effect	Nexplanon (Implant)	Hormonal IUD (e.g., Mirena)	Combination Pill
Hormone Type	Progestin-only (etonogestrel) [1.9.1]	Progestin-only (levonorgestrel) [1.6.1]	Estrogen and Progestin [1.6.4]
Common Side Effects	Irregular bleeding, headache, weight gain, acne, mood swings [1.3.1].	Irregular bleeding (often becomes lighter), cramping, ovarian cysts [1.6.1, 1.6.2].	Breast tenderness, headaches, nausea, mood changes. Risk of blood clots is higher than with progestin-only methods [1.6.4, 1.11.4].
Systemic Effects	Hormones are systemic (circulate throughout the body) [1.7.3].	Hormones are mostly localized to the uterus, with lower systemic absorption [1.6.5].	Hormones are systemic [1.6.4].
User Action	"Set it and forget it" for 3 years [1.8.1].	"Set it and forget it" for 3-8 years depending on type [1.6.2].	Must be taken daily [1.6.4].

Conclusion

Nexplanon offers a highly effective, long-term, and convenient form of birth control. However, the downsides are significant and should be carefully considered. The most prevalent issue is the unpredictable change in menstrual bleeding patterns, which is the top reason for discontinuation [1.5.1]. Other common side effects like weight gain, headaches, acne, and mood disturbances also affect a notable percentage of users [1.5.1]. While serious risks such as blood clots, ectopic pregnancy, and implant migration are rare, they are severe and require awareness [1.3.2]. A thorough discussion with a healthcare provider about one's medical history and lifestyle is crucial to determine if the benefits of Nexplanon outweigh its potential downsides.

For more information directly from the manufacturer, you can visit the official Nexplanon website.

Frequently Asked Questions

In clinical studies, 13.7% of users reported weight gain [1.5.1]. The average gain was about 2.8 pounds after one year and 3.7 pounds after two years [1.7.4]. However, research is mixed on whether the implant is the direct cause, as some studies show similar weight gain in non-users [1.9.1].

Yes, mood swings, emotional lability, and depression are recognized side effects and a reason some women stop using the implant [1.8.1]. In clinical trials, 6.5% of users reported emotional lability and 5.5% reported depression [1.5.1].

The most common downside and the primary reason for discontinuation is a change in menstrual bleeding patterns. This can include irregular, frequent, prolonged, or absent periods [1.3.2, 1.5.1].

Yes, though it is rare, the implant can move (migrate) from its original position. In very rare cases, it has been reported to travel through a blood vessel to other parts of the body, like the chest. If the implant cannot be felt, it may be difficult or impossible to remove without special procedures like surgery [1.4.2, 1.10.2].

Yes, Nexplanon may increase the chance of developing serious blood clots, particularly in the legs, lungs, brain, or heart [1.11.2]. The risk is higher for women who smoke or have other risk factors for blood clots [1.11.1].

A trained healthcare professional will numb the area, make a small incision, and remove the implant. Potential side effects of removal include pain, bruising, scarring, or infection at the site. Difficulty can arise if the implant has moved or is encased in scar tissue [1.10.1, 1.4.2].

It is very rare, as Nexplanon is over 99% effective [1.8.3]. If pregnancy does occur, there is a slightly higher risk of it being an ectopic pregnancy, which requires immediate medical attention [1.11.2].

Some side effects, like those at the insertion site, may last a few days. Others, like changes in menstrual patterns, may persist for as long as you use the implant. For many, side effects may improve after the first few months, but if they are bothersome, the implant can be removed [1.3.4, 1.7.1].