Understanding How Does the Coil Stop Periods?

October 9, 2025 •

5 min read

Approximately 20% of users with the higher-dose levonorgestrel hormonal coil (IUD) experience amenorrhea, or cessation of their periods, within the first year. This phenomenon is a key reason many individuals ask, "How does the coil stop periods?"

Quick Summary

Hormonal coils release progestin, which thins the uterine lining and thickens cervical mucus. This inhibits the buildup of endometrial tissue, resulting in significantly lighter menstrual flow or the complete cessation of periods.

Key Points

Hormonal IUDs (Coils): These devices release a progestin hormone that acts locally to thin the uterine lining, which is the primary reason periods become lighter or stop.
Endometrial Thinning: By preventing the endometrium from thickening, hormonal coils leave very little tissue to be shed, thus reducing menstrual flow.
Non-Hormonal IUDs: Copper IUDs do not use hormones and therefore do not stop periods; they often cause heavier and longer bleeding instead.
Gradual Effect: The process of periods stopping with a hormonal coil is not immediate. It involves an adjustment period of three to six months with irregular spotting before flow decreases and potentially ceases.
Mechanism of Action: The hormonal coil's action is localized to the uterus, meaning the progestin mainly affects the endometrial lining and cervical mucus, not systemic hormone levels like the pill.
Expected Change: After a year, about 20% of users of higher-dose hormonal IUDs may experience amenorrhea (no period), while many others will have very light bleeding.

The term 'the coil' most often refers to an intrauterine device (IUD), a small, T-shaped birth control device inserted into the uterus. There are two main types of IUDs: hormonal and non-hormonal (copper). Their effects on the menstrual cycle differ dramatically, and understanding this distinction is crucial when asking how the coil stops periods.

The Mechanism Behind Hormonal IUDs and Menstrual Suppression

The ability of certain coils to stop periods is primarily associated with hormonal IUDs, such as Mirena, Kyleena, and Skyla. These devices release a synthetic form of the hormone progesterone called progestin (specifically, levonorgestrel) directly into the uterus. The progestin works locally within the uterine cavity, which is key to its effects on menstruation.

Thinning the Endometrial Lining

The main pharmacological action that leads to reduced or absent periods is the thinning of the uterine lining, or endometrium. Normally, during a menstrual cycle, the endometrium thickens in preparation for a potential pregnancy. If no pregnancy occurs, the lining is shed, resulting in a menstrual period. The continuous release of progestin from a hormonal IUD suppresses the growth of the endometrial lining, preventing it from thickening as it normally would. With very little tissue to shed, menstrual bleeding becomes significantly lighter and may eventually cease altogether. This is why the hormone-releasing IUDs are often used as a treatment for heavy menstrual bleeding, also known as menorrhagia.

Other Contraceptive Effects of Progestin

While thinning the uterine lining is the key to stopping periods, the progestin also provides other contraceptive benefits:

Thickening cervical mucus: The hormone makes the mucus in the cervix thicker and stickier, creating a barrier that makes it difficult for sperm to enter the uterus.
Inhibiting sperm motility: The local presence of the hormone in the uterus inhibits the movement and function of sperm.
Partially suppressing ovulation: Although it is not the primary mechanism, the progestin can also partially or completely suppress ovulation in some women, particularly with higher-dose IUDs.

Why Non-Hormonal Coils Don't Stop Periods

It is a common misconception that all IUDs stop or lighten periods. The non-hormonal coil, such as the ParaGard copper IUD, has a completely different mechanism of action and effect on menstruation.

The Action of Copper IUDs

Instead of hormones, the copper IUD releases copper ions into the uterus. This creates a local inflammatory response that is toxic to sperm, preventing them from fertilizing an egg. This mechanism does not affect the hormonal cycle or the uterine lining's natural buildup and shedding.

Effect on Menstrual Flow

In fact, the copper IUD is known to often cause heavier and longer periods, especially during the first few months of use. For some individuals, this effect may persist, which is an important consideration for those who already have heavy menstrual flow. The increased bleeding is a result of the inflammatory reaction caused by the copper within the uterus.

What to Expect After Hormonal IUD Insertion

After getting a hormonal IUD, the body needs time to adjust to the new, localized hormone levels. This transition period often involves a few changes to the menstrual cycle:

Initial bleeding and spotting: It is common to experience irregular spotting or light, unpredictable bleeding for the first three to six months. This is a normal part of the body adjusting to the thinning uterine lining.
Lighter, shorter periods: Following the initial adjustment period, menstrual bleeding typically becomes lighter and shorter each month.
Cessation of periods (amenorrhea): For a significant portion of users, periods may stop entirely. The likelihood of this happening depends on the specific type of hormonal IUD, with higher-dose options like Mirena or Liletta having a greater chance of inducing amenorrhea. One study showed that nearly 20% of users experience at least one 90-day interval of amenorrhea during the first year of using a higher-dose levonorgestrel IUD.

A Comparison of IUD Effects on Periods


Feature	Hormonal IUD (e.g., Mirena)	Non-Hormonal IUD (Copper)
Primary Mechanism	Releases progestin (levonorgestrel) locally to thin uterine lining.	Releases copper ions to create a spermicidal inflammatory response.
Effect on Periods	Progressively lighter, shorter periods; often leads to complete cessation (amenorrhea).	Often causes heavier, longer, and more painful periods, particularly in the initial months.
Impact on Ovulation	May suppress ovulation in some women, though not the primary action.	Does not suppress ovulation; the user's natural cycle continues.
Menstrual Cramps	Often reduces menstrual cramps, making it a treatment for painful periods.	Can cause or increase menstrual cramps.
Period Blood Fate	No blood is shed because the lining doesn't build up sufficiently.	Normal shedding of the uterine lining occurs, sometimes with increased blood flow.
Recommended for Heavy Periods?	Yes, it is often prescribed as a treatment for menorrhagia.	No, it is generally not recommended for individuals with already heavy periods.

How Your Periods Stop on a Hormonal Coil

Here is a step-by-step breakdown of how a hormonal coil works to suppress your period:

Insertion: A healthcare provider inserts the small, T-shaped device into your uterus.
Hormone Release: The IUD begins releasing a steady, low dose of the progestin levonorgestrel directly into the uterine cavity.
Endometrial Thinning: The progestin immediately begins to inhibit the natural thickening of the uterine lining.
Reduced Shedding: With insufficient tissue buildup, the amount of endometrial tissue to be shed during menstruation is significantly reduced.
Amenorrhea: Over several months, as the lining remains thin, menstrual bleeding becomes lighter and may eventually stop entirely for some users.

Conclusion

In conclusion, the answer to how the coil stops periods lies in the pharmacological action of the progestin-releasing, hormonal IUD. By delivering a continuous, low dose of levonorgestrel directly to the uterus, it prevents the endometrial lining from thickening, leading to lighter or completely absent periods. This is in stark contrast to the non-hormonal copper IUD, which works by creating a spermicidal inflammatory response and can lead to heavier menstrual bleeding. Understanding these distinct mechanisms is vital for individuals considering an IUD, especially if altering their menstrual cycle is a primary consideration for their contraceptive choice. For the most accurate and personalized advice, it is always best to consult with a healthcare professional.

This article is for informational purposes only and is not a substitute for professional medical advice. Always consult with a qualified healthcare provider for any questions about a medical condition or treatment.

Frequently Asked Questions

No, the copper coil does not stop periods. As it is non-hormonal, it does not thin the uterine lining. In fact, many users experience heavier and longer periods, particularly in the first few months after insertion.

With a hormonal IUD, period blood doesn't go anywhere because there is little or no menstrual bleeding to begin with. The progestin thins the uterine lining to the point that there is very little tissue to shed, which is why periods become lighter or stop.

The cessation of periods is a gradual process. In the first three to six months, you may experience irregular spotting or light bleeding. Over the next year, flow will typically decrease, and for some, periods will stop completely, depending on the specific IUD.

No, not all hormonal IUDs have the same effect. Higher-dose IUDs like Mirena are more likely to cause amenorrhea (no periods), with around 20% of users experiencing this by the end of the first year. Lower-dose IUDs like Skyla may cause very light periods but are less likely to stop them entirely.

It is highly unlikely to get pregnant while using a hormonal IUD correctly, even if your periods have stopped. The coil is a very effective form of contraception. If you are concerned, you can take a pregnancy test, but for most users, no period simply means the IUD is working as intended.

Many people choose a hormonal coil for its ability to significantly lighten or stop periods. It can be a very effective treatment for medical conditions like menorrhagia (heavy menstrual bleeding) and endometriosis, reducing pain and discomfort.

If your periods return after a period of amenorrhea, especially if accompanied by other symptoms like pain or unusual discharge, it's a good idea to consult your healthcare provider. It could be a sign of normal hormonal fluctuation or, in rare cases, that the IUD has moved or is nearing the end of its effectiveness for period control.

For most individuals, stopping periods with a hormonal IUD is safe and an intended effect of the device. It is not harmful, as there is no blood trapped inside the body. However, discussing your medical history with a doctor is essential to ensure a hormonal IUD is the right choice for you.