Pregnancy Sickness as Adaptation: A Deterrent to Maternal Ingestion of Teratogens

Abstract

The adaptationist approach to the phenomena of life, which entails recognizing certain features of organisms as specialized problem-solving mechanisms (Williams, 1985), is the basis for physiological research (Mayr, 1983). Even physiological phenomena that are commonly assumed to be anomalies or pathologies, such as human pregnancy sickness, can sometimes be illuminated by asking the adaptationist questions: Has the phenomenon been designed by natural selection to serve some function? If so, what is that function? Whether a physiological process like pregnancy sickness is an adaptation or merely a by-product of other physiological processes can be assessed by determining whether it achieves an adaptive end with sufficient precision, economy, efficiency, and complexity to indicate functional design (Williams, 1966).