Introvale is a prescription birth control pill designed to give you only four periods per year instead of the usual twelve. It’s the generic equivalent of Seasonale, manufactured by Sandoz, and contains the same two hormones found in many combination birth control pills: a progestin and an estrogen. What makes Introvale different from a standard pill pack is the schedule. Instead of 21 active pills followed by 7 inactive ones each month, Introvale comes in a 91-day cycle.
How the 91-Day Cycle Works
Each Introvale pack contains 91 pills arranged in 12 rows of 7 tablets. The first 84 pills are peach-colored active tablets, each containing 0.15 mg of levonorgestrel and 0.03 mg of ethinyl estradiol. The final 7 pills are white and inactive, containing no hormones at all.
You take one active pill at the same time every day for 84 consecutive days (12 weeks). Then you switch to the 7 white pills for week 13. Your period arrives during that final week. Once you finish the pack, you start a new one the next day. The result is roughly four scheduled periods per year, each lasting about a week, with three months of continuous hormone coverage in between.
How Introvale Prevents Pregnancy
Introvale works the same way other combination birth control pills do. The two hormones prevent your egg from fully developing each month, so fertilization can’t occur. They also thicken cervical mucus, making it harder for sperm to reach an egg in the first place.
With typical, real-world use, combination birth control pills have a failure rate of about 9% per year. With perfect use (taking the pill at the same time every day, never missing a dose), that drops to 0.3%. The extended cycle doesn’t change these numbers. Introvale’s effectiveness depends on how consistently you take it, just like any other combination pill.
Benefits Beyond Pregnancy Prevention
Having fewer periods isn’t just a convenience. Extended-cycle pills like Introvale can help manage several conditions that flare around menstruation. They’re used to prevent and treat heavy bleeding related to uterine fibroids, relieve pain from endometriosis, reduce menstrual migraines, and lessen the worsening effect that periods can have on seizure disorders. For people whose symptoms are tied to their menstrual cycle, going from twelve periods a year to four can make a meaningful difference in quality of life.
Breakthrough Bleeding and Spotting
The most common side effect specific to extended-cycle pills is spotting or light bleeding between your scheduled periods. This is more likely with Introvale than with traditional monthly pill packs, especially during the first few months of use. It’s not a sign that the pill isn’t working, and it typically becomes less frequent over time as your body adjusts to the longer hormone cycle. Many people find it resolves significantly after the first one or two 91-day packs.
What to Do If You Miss a Pill
Missing one active pill is straightforward: take it as soon as you remember, then take the next pill at your regular time. You may end up taking two pills in one day, but no backup contraception is needed.
If you miss two consecutive active pills, take two pills the day you remember and two the next day, then resume your normal one-per-day schedule. Use a backup method like condoms for the next 7 days.
If you miss three or more active pills in a row, don’t try to catch up on the missed ones. Just continue taking one pill per day going forward and use backup contraception for the next 7 days.
Who Should Not Take Introvale
Introvale carries the same contraindications as other combination birth control pills, and the most prominent risk involves blood clots. Cigarette smoking significantly increases the risk of serious cardiovascular events, and that risk climbs with age and the number of cigarettes smoked. If you’re over 35 and smoke, combination pills including Introvale are not an option.
Introvale is also contraindicated for people with:
- A history of blood clots in the legs or lungs
- Coronary artery disease or stroke
- Certain heart valve or rhythm conditions
- Uncontrolled high blood pressure, or high blood pressure with vascular disease
- Migraines with aura at any age, or any migraines if over 35
- Diabetes with vascular complications, or diabetes if over 35
- Current or past breast cancer
- Liver tumors, acute hepatitis, or severe cirrhosis
- Undiagnosed abnormal uterine bleeding
Medications That Can Reduce Effectiveness
Certain drugs speed up how quickly your body breaks down the hormones in Introvale, potentially making it less effective. The list includes several anti-seizure medications (carbamazepine, phenytoin, topiramate, oxcarbazepine, felbamate, rufinamide), the antibiotic rifampin, the antifungal griseofulvin, and the herbal supplement St. John’s wort. Some HIV and hepatitis C medications also interfere with hormone levels.
A cholesterol-lowering medication called colesevelam can reduce how much estrogen your body absorbs from the pill, which may lower its effectiveness or trigger breakthrough bleeding. If you’re taking any of these medications, backup contraception or an alternative birth control method is recommended.
Introvale vs. Seasonale
Introvale is the FDA-approved generic equivalent of Seasonale. Both contain the same hormones at the same doses (0.15 mg levonorgestrel, 0.03 mg ethinyl estradiol), follow the same 91-day schedule, and have the same 84 active pills plus 7 inactive pills. The difference is cost. As a generic, Introvale is typically less expensive than the brand-name version while delivering identical contraceptive protection.