Table 2.

Developmental endpoints vulnerable to environmental disruption

Category	Description and comment
Growth	Growth in all its manifestations (body size, birth weight and rate of growth) is sensitive to environmental insults (60, 61). While growth is sensitive, it is not specific to environmental exposures, because many factors influence growth, including; genetic, nutrition, maternal disease, tobacco smoke, alcohol, maternal education and socioeconomic status. In characterizing fetal and neonatal growth special attention needs to be given to gestational and postnatal age (62-67).
Functional abnormality	Functional abnormalities, typically identified after birth, may be a consequence of environmental exposure prior to or during pregnancy. Neurodevelopmental impairment resulting from prenatal lead exposures represents an example (33, 68-73). Either paternal or maternal lead exposure increases the risk of spontaneous abortion and impairs fetal growth and postnatal neurodevelopment. Because maternal bone lead is mobilized during pregnancy, exposures producing abnormal fetal development may have occurred many years prior to the pregnancy (73). Other functional abnormalities are included in the emerging literature on developmental origins of health and disease (41, 44, 74, 75).
Structural abnormality	Traditional concern about exposures in pregnancy has focused on birth defects or structural abnormalities. There are ∼50 chemicals, ∼15 infectious agents and several physical agents known to produce human structural malformations (1, 7, 9, 76, 77).
Death	A common developmental consequence of a chromosomal or genetic abnormality is embryonic, fetal or neonatal death (10). There are data suggesting an association between certain paternal occupations and increased risk of mortality (11, 78). Additionally, there are data linking a variety of environmental exposures with embryonic, fetal and neonatal mortality (8, 79).
Gestational length	Prematurity has not been a traditional developmental endpoint, however, given the increasing evidence that it is susceptible to environmental exposures (3), the life-long consequences of prematurity, and the persistence of prematurity as a public health problem it will also be considered as an endpoint of abnormal development in this review (80, 81).