Lo Loestrin Fe is a 28-day birth control pill pack containing three types of pills taken in a specific order: 24 blue active pills, 2 white pills, and 2 brown iron pills. You take one pill every day at the same time, with no breaks between packs.
What Each Pill Color Means
The blue pills are your main contraceptive tablets, containing both a progestin and a low-dose estrogen. You take these for the first 24 days of your pack. Days 25 and 26 are white pills, which contain only estrogen. Days 27 and 28 are brown pills, which contain only iron (ferrous fumarate) and no hormones at all.
The brown pills exist to keep you in the habit of taking a pill daily and to provide a small iron supplement. They have no contraceptive effect. If your period arrives, it will typically come during the brown pill days, though many people on Lo Loestrin Fe have very light periods or skip them entirely.
When to Start Your First Pack
The simplest approach is a Day 1 start: take your first blue pill on the first day of your period (the day bleeding or spotting begins, even if it starts late at night). When you start on Day 1, no backup contraception is needed because the hormones align with your natural cycle timing.
If you start on any other day, use a non-hormonal backup method, like condoms, for the first 7 days. Your pack comes with a day label strip. Peel the strip that starts with the day of the week your period begins and place it over the printed days on your dispenser so you can easily track where you are in the pack.
Daily Timing and Consistency
Pick a time of day and stick with it. Taking your pill at the same time every day is the single most important habit for effectiveness. Many people pair it with a daily routine: brushing teeth at night, a morning alarm, or a meal. The prescribing information does not specify whether to take it with food, so choose whatever helps you stay consistent.
What to Do If You Miss a Pill
If you miss one blue pill, take it as soon as you remember, even if that means taking two blue pills in one day. Then continue the rest of the pack on your normal schedule. Use backup contraception for the next 7 days to be safe.
If you miss two or more blue pills, the risk of unintended pregnancy increases. Take the most recently missed pill as soon as you remember (skip any earlier missed pills), continue the pack on schedule, and use backup contraception for at least 7 days. If you had unprotected sex during the days you missed pills, emergency contraception is worth considering.
Missing a white or brown pill is less critical. The white pills contain a small amount of estrogen, and the brown pills contain only iron. If you miss either, simply discard the missed pill and continue with the next one on schedule. You do not need backup contraception for missed brown pills.
Vomiting or Diarrhea After Taking a Pill
If you vomit or have diarrhea within 3 to 4 hours of taking a blue or white pill, your body may not have absorbed the hormones. Treat this the same as a missed pill: follow the missed dose instructions above. If the stomach illness lasts several days, use backup contraception until you’ve taken active pills consistently for a full week after recovering.
How Effective It Is in Practice
In the clinical trial used for FDA approval, the pregnancy rate was about 2.9 per 100 women per year. Notably, at least 25 of the 28 pregnancies in that trial occurred among women who reported taking the pill correctly. This is a reminder that even with consistent use, no hormonal contraceptive is 100% effective, and real-world effectiveness depends heavily on daily timing.
Medications That Can Reduce Effectiveness
Several common medications speed up how quickly your liver processes hormones, which can lower the amount of contraceptive in your bloodstream. The most significant include:
- Seizure medications: carbamazepine, oxcarbazepine, phenytoin, felbamate, topiramate
- Antibiotics and antifungals: rifampin, griseofulvin
- Barbiturates
- St. John’s wort, a widely available herbal supplement for mood
- Bosentan, used for pulmonary arterial hypertension
If you take any of these, you may need an additional or alternative contraceptive method. St. John’s wort is the one that catches people off guard because it’s sold over the counter and rarely mentioned during pharmacy consultations.
Switching From Another Birth Control
If you’re switching from a different combination pill, start Lo Loestrin Fe the day after you take the last active pill in your old pack (skip any placebo pills from the previous brand). If you’re switching from a progestin-only pill, start Lo Loestrin Fe the next day and use backup contraception for the first 7 days. When switching from an implant or IUD, start Lo Loestrin Fe on the day of removal and use backup for 7 days.
Keeping Track of Your Pack
Each pack runs exactly 28 days. When you finish the last brown pill on day 28, start a new pack the very next day. There is no pill-free gap between packs. If you find yourself confused about where you are in the pack, the day label strip on the dispenser is your best reference. Setting a daily phone alarm with a label like “blue pill” or “brown pill” can also help you stay oriented through each phase of the cycle.