Levonorgestrel is a progestin used in several forms (emergency contraception, mini-pills, combined oral contraceptives, and LNG-releasing IUD). Side effects vary somewhat by product, but here’s a practical overview.
Common side effects (general to LNG-containing products)
- Nausea or vomiting
- Headache
- Breast tenderness
- Mood changes or irritability
- Weight changes or fluid retention
- Acne or skin changes
- Irregular bleeding or spotting between periods
- Changes in menstrual flow (heavier, lighter, or delayed periods)
Side effects by product type
- Emergency contraception (e.g., Plan B)
- Common: nausea, fatigue, headache, dizziness, breast tenderness, abdominal pain
- Menstrual changes: your next period may be earlier or later than usual, may be heavier or lighter
- Usually short-lived; if vomiting occurs within 2 hours, you may need to repeat dose
- Progestin-only pill (mini-pill)
- Common: irregular bleeding or spotting, especially in the first months
- May cause headaches, breast tenderness, mood changes, nausea
- Some people experience amenorrhea (no period) after regular use
- Combined oral contraceptives containing levonorgestrel
- Common: nausea, breast tenderness, headaches, mood changes, weight changes
- Bleeding pattern changes: breakthrough bleeding or spotting between periods
- Occasionally hair changes or changes in libido
- LNG-releasing intrauterine device (IUD)
- Common early effects: cramping, irregular or heavier bleeding for a few cycles
- Over time: many people have lighter periods or may stop having periods (amenorrhea)
- Possible but rare issues: expulsion (device comes out), perforation during insertion, or infection
- Some may notice changes in acne or skin; usually not a systemic effect
Serious but rare side effects and warning signs (seek care promptly)
- Signs of a blood clot: new or worsening leg swelling/pain, chest pain, shortness of breath, coughing blood
- Severe allergic reaction: trouble breathing, swelling of face/lips/tongue, severe dizziness or hives
- Severe or persistent abdominal pain, severe headache with vision changes or confusion
- Jaundice (yellowing of skin or eyes), dark urine, pale stools
- Severe or unusual vaginal bleeding or foul-smelling discharge (infections or other issues)
- For IUD users: fever with abdominal tenderness, concerning vaginal discharge, or inability to feel the string
Who should be cautious or avoid LNG-levonorgestrel products
- Pregnant or suspected pregnancy
- Undiagnosed vaginal bleeding or a history of certain liver or breast cancers
- History of thromboembolic disease (blood clots), stroke, heart attack, severe hypertension, or certain heart/liver conditions
- Smokers over about 35 years old (higher risk with some hormone methods)
- Known allergy to levonorgestrel or other components
Drug interactions (brief)
- Some anticonvulsants, certain antibiotics (e.g., rifampin), St. John’s wort, and other drugs can reduce effectiveness of LNG-containing methods
- If you take other long-term medications, check with a clinician or pharmacist to be sure there’s no interaction
What to do if you experience side effects
- Mild side effects: often improve in a few days to a couple of cycles; taking with food or at a consistent time may help
- Persistent or bothersome side effects: talk with your healthcare provider about possibly changing methods or adjusting management
- If you suspect a serious side effect or signs of a blood clot or severe allergy, seek urgent medical care
If you’d like, tell me which levonorgestrel product you’re using (emergency contraception, mini-pill, a combined pill, or a LNG IUD). I can tailor the information to that method and your situation.