DART studies are long, complex and expensive, so you need to plan them carefully
DART studies often need multiple groups of adults and off-spring and a large range of varied endpoints. More complex studies, like OECD 443, have additional breeding phases that can be triggered by effects observed during the conduct of the study which adds to the already complicated nature of the study. You will be investing a lot in DART studies, so you need to be confident of reliable outcomes that will satisfy regulatory requirements.
Some endpoints are difficult to measure reliably, and lack of historic datasets makes interpretation difficult
Behavioral, histopathological, anatomical and chemical endpoints can be required for DART studies. You need a validated team with the necessary expertise, facilities and equipment to conduct these assessments. Analytics in offspring and fetuses can be difficult as chemical assays must detect the low concentrations that occur in young animals. This is especially problematic for thyroid hormone testing for endocrine disruptor endpoints. In addition, it is important to ensure Historical Control is available for newer tests like endocrine disruptor endpoints.
DART studies can give you logistical headaches
DART studies are complex because they involve the mating of animals and management of multiple groups of adults and offspring. As the day of mating during the pairing period varies, DART study logistics can be unpredictable. The study start may span several days and involve peaks in test requirements related to peaks in mating and littering. This can cause you serious resource challenges over the course of a study.