What is the first step in the workup for elevated maternal serum alpha-fetoprotein (MSAFP)?

The initial step in the workup for elevated maternal serum alpha-fetoprotein (MSAFP) is to verify gestational age. This is crucial because MSAFP levels vary significantly with gestational age. An accurate determination of the gestational age helps in interpreting the MSAFP levels appropriately. For instance, a higher MSAFP could be considered normal in a later gestational age compared to an earlier gestational age. If the gestational age is miscalculated, it may lead to unnecessary anxiety or invasive testing without adequate justification. Therefore, establishing an accurate gestational age is the foundation that guides further evaluation and management decisions.