The morning-after pill, also known as emergency contraception, serves as a backup method to prevent pregnancy after unprotected sex or contraceptive failure. It is for occasional, emergency use, not a regular form of birth control.
How the Morning After Pill Influences Your Cycle
The morning-after pill primarily works by temporarily altering the body’s hormonal balance. Most common types contain a high dose of levonorgestrel or ulipristal acetate. These hormones delay or prevent ovulation, the release of an egg. If ovulation does not occur, no egg is available for fertilization, preventing pregnancy.
The effectiveness of these pills depends on when they are taken relative to the menstrual cycle and unprotected sex. Levonorgestrel-based pills are most effective within 72 hours (three days), while ulipristal acetate works for up to 120 hours (five days). By disrupting hormonal signals that lead to ovulation, the pill can temporarily affect the timing and characteristics of your subsequent menstrual period.
Common Period Changes After Taking the Pill
Taking the morning-after pill can lead to temporary changes in your menstrual cycle. Your next period may arrive earlier or later than expected. A delay of up to one week is common, but periods can also come a few days early.
Beyond timing, changes in menstrual flow and duration are also possible. You may notice a heavier or lighter flow than usual, or the period might last for a different length of time. Irregular bleeding or spotting between periods is another common effect. This light, short-lived spotting results from hormonal fluctuations. These menstrual changes are generally confined to the cycle immediately following the pill’s use, and your cycle should return to its typical pattern afterward.
Other Temporary Effects You Might Experience
The morning-after pill can cause other temporary side effects. These are generally mild and resolve within a few days. Common symptoms include nausea and, less frequently, vomiting. Taking the pill with food might help reduce nausea.
Other temporary effects include headaches, dizziness, fatigue, breast tenderness, or abdominal pain and cramping. These side effects are a normal response to the high dose of hormones in the medication.
When to Consult a Healthcare Provider
Most morning-after pill effects are temporary and not a cause for concern, but contact a healthcare provider in specific situations. Seek medical advice if your period is significantly delayed, especially if it is more than a week late. A pregnancy test is recommended if your period is delayed by more than seven days or does not arrive within three to four weeks of taking the pill.
Concerns about pregnancy despite taking the pill, or new pregnancy symptoms, warrant a consultation. Additionally, contact a healthcare provider if you experience severe abdominal pain, unusually heavy vaginal bleeding, or ongoing spotting that lasts longer than a week. If vomiting occurs within a few hours of taking the pill, its effectiveness might be reduced; ask a professional if another dose is needed.