To describe the natural history of a condition or disease. To describe the natural history of a condition or disease. To determine effectiveness or cost effectiveness of treatments/services and/or health care products. To measure or monitor safety and harm. To measure quality of care.
According to the NMSS, attacks or flare-ups of symptoms only qualify as exacerbations if: 1  they occur at least 30 days from an earlier flare-up. 2  symptoms last for 24 hours or longer.
âImplantation bleeding (also known as spotting) usually lasts for a couple of days but every woman is different, so how long it lasts can vary. Sometimes itâs less than a day, occasionally itâs longer than a couple of days,â says Dr Rob Hicks.