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Took plan b. Light period came today. Lot of blood, less than usual. When can I take pregnancy test? Are light periods a side effect of plan b?

1 doctor weighed in
Dr. Robert Kwok
Pediatrics

In brief: 3 weeks after sex

A urine pregnancy test done correctly will give a reliable result 3 weeks after sex (or when conception might have happened) or 1 week after missing a period.
If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test. If a woman has her normal regular period, then she is not pregnant, and the test is not needed yet.

In brief: 3 weeks after sex

A urine pregnancy test done correctly will give a reliable result 3 weeks after sex (or when conception might have happened) or 1 week after missing a period.
If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test. If a woman has her normal regular period, then she is not pregnant, and the test is not needed yet.
Dr. Robert Kwok
Dr. Robert Kwok
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