Whole embryo culture: interpretation of abnormal development in vitro

An overview will be given of a number of problems that arise when we attempt an interpretation of data obtained with the whole embryo culture method (WEC). The following aspects will be considered: 1) Types of deviation from normal development in the whole-embryo culture system: (a) problem of "artifacts" (for example, due to preparation mistakes and suboptimal culture conditions), (b) types and frequency of abnormal development in controls, retardation as an abnormal outcome, and the difficulty of assessing its significance, (c) gross-structural defects and, specifically, attempts to answer the following questions: (i) What are the limitations for an assessment of abnormal development with the WEC? (ii) Is a specific abnormality pattern recognizable under specific pathologic conditions? (iii) Is the rate of induced abnormal development concentration-dependent? (2) Problems encountered when interpreting concentration-effect relationships (for example, statistical and pharmacokinetic aspects). (3) Necessity of verifying in vitro effects with in vivo studies.