Mirena is a long-acting reversible contraceptive (LARC) device that releases the hormone levonorgestrel directly into the uterus. Used for pregnancy prevention and managing heavy periods, a common side effect is spotting—light, unscheduled bleeding outside of a normal menstrual cycle. Understanding the physiological reasons for this bleeding and knowing how to manage it can help users continue with this birth control option.
Why Mirena Causes Spotting
Mirena-related spotting results from the localized action of the progestin levonorgestrel within the uterine cavity. This hormone causes the endometrium (the uterine lining) to thin. This process, known as endometrial atrophy, creates an unstable lining prone to irregular, light shedding and bleeding. This bleeding is not harmful and is a normal part of the body’s adjustment to the device.
Spotting is most frequent during the first three to six months following insertion. During this initial phase, the number of bleeding days may increase, and the pattern is irregular. For most users, this irregularity improves significantly, and spotting typically resolves by the six-to-twelve-month mark. Many women eventually experience a substantial reduction in blood flow, and up to 20% stop menstrual bleeding entirely after one year.
Immediate Steps for Managing Spotting
Managing initial spotting involves simple strategies to reduce the inconvenience and frequency of bleeding. One effective non-prescription method is the temporary use of over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs). Taking medications like ibuprofen or naproxen during a spotting episode can help reduce the volume of blood flow and alleviate any associated cramping.
Managing the initial spotting often involves simple, actionable strategies. Since any form of bleeding causes blood loss, maintaining adequate iron intake through diet or supplements is a sensible strategy. Certain lifestyle factors, such as smoking, are associated with increased irregular bleeding in users of hormonal contraception. Avoiding smoking and managing high stress levels can help promote general uterine health and stability during the adjustment period.
When Professional Intervention is Needed
If spotting persists and is bothersome after the initial six-month adjustment period, consult a healthcare provider. The provider will typically perform a pelvic examination to confirm the Mirena device is correctly positioned within the uterus. Displacement or partial expulsion is a rare cause of persistent bleeding, and a simple ultrasound may be used to verify proper placement.
If the device is correctly seated, the doctor may recommend hormonal “add-back” therapy. This usually involves prescribing a low-dose oral estrogen or a combination birth control pill for one to three months. This hormonal boost is designed to stabilize and strengthen the uterine lining, often resulting in a cessation of prolonged spotting. If bleeding remains intolerable and persistent after a full year despite these interventions, removing the device and exploring alternative contraceptive methods may be necessary.
Recognizing Serious Symptoms
While light spotting is expected, certain symptoms indicate a serious issue requiring immediate medical attention. Report any sudden onset of extremely heavy bleeding, such as soaking through one or more sanitary pads every hour for several hours, to a doctor right away. Severe, unrelenting abdominal or pelvic pain that is not relieved by over-the-counter medication is also a concerning symptom.
Signs of a possible infection, such as fever, chills, or a foul-smelling vaginal discharge, demand prompt evaluation. Users should also check for signs of device movement, like missing or significantly shortened strings, or if they can feel the plastic of the device itself. If a user experiences unexpected bleeding along with pain and a missed period, they should seek urgent care to rule out an ectopic pregnancy.