When an oral contraceptive pill is swallowed, the hormones must be absorbed through the digestive system into the bloodstream to maintain their protective effect. Vomiting shortly after taking the pill interrupts this process, meaning the body may not have absorbed enough hormones to prevent ovulation. This loss compromises the pill’s effectiveness, requiring immediate action to restore contraceptive protection.
The Critical Absorption Window
The factor determining whether the pill’s protection is lost is the time between swallowing the tablet and the episode of vomiting. For most combined oral contraceptive pills, which contain both estrogen and progestin, the hormones are absorbed within a two to three-hour period after ingestion. This timeframe reflects how quickly the tablet breaks down and its active ingredients are taken up by the small intestine.
If vomiting occurs more than three hours after taking an active pill, the body has likely absorbed enough hormones, and the pill’s efficacy is maintained. No immediate action is necessary, and the user can take the next pill at the regularly scheduled time. Conversely, if vomiting occurs within the two-to-three-hour window, the episode must be treated as a missed pill, requiring immediate attention to prevent a lapse in protection.
Immediate Steps for Re-Dosing
If vomiting happens within the three-hour absorption window, the user should assume the pill was not absorbed and take a replacement pill immediately. This replacement pill must be an active hormone tablet taken from the current pack, not a placebo. Taking this extra pill restores the necessary hormone levels, replacing the lost dose.
After taking the replacement dose, the user should continue the rest of the pill pack as scheduled, taking the next pill at the usual time. This may mean taking two active pills on the same day, which is a safe protocol for managing a missed dose. If vomiting is persistent and the user cannot keep the replacement pill down, they should wait until nausea subsides or consult a healthcare provider. If prolonged illness causes vomiting for more than 24 hours, the user must follow the protocol for multiple missed pills.
When to Use Backup Contraception
Even after taking a replacement pill, the user must implement a backup method of contraception, such as condoms, to ensure protection is fully restored. The effectiveness of the pill may be temporarily reduced following the disruption of hormone levels. The standard protocol requires using a barrier method or abstinence for the subsequent seven consecutive days of taking active hormone pills.
The seven-day rule ensures that the steady level of hormones necessary to suppress ovulation is re-established. If vomiting occurred during the first week of a pill pack and unprotected sexual intercourse happened in the five days preceding the vomiting, there is an increased risk of pregnancy. In this situation, the user should consider taking emergency contraception (EC) in addition to re-dosing the pill and using a barrier method for seven days.
A healthcare professional should be contacted if the vomiting is severe or lasts for two or more days, as this prolonged illness could affect the absorption of multiple pills and necessitate a change in contraceptive strategy. Seeking professional advice is also important if EC is considered, as some types of emergency contraception, such as ulipristal acetate, may interact with the hormones in the regular birth control pill.