In search of the true inception cohort

Prognostic studies hinge on the assembly of a proper inception cohort. The stepwise assembly of a "true" inception cohort of hypertension complicating pregnancy is reported. Standard assembly procedures would have resulted in the preferential reporting of the severest cases of the prognostically worst categories of disease. The less severe cases would have been missed. Prognostic studies should utilize and report a method for assessing potential missed cases, such as a random selection of records for independent review.