ABSTRACT
IV. Other Factors in Assessing Developmental Effects 20 A. Male-mediated effects 20 B. Developmental variations 21 C. The modifying influence of maternal toxicity and designation of ‘‘teratogen’’ 23 D. Pharmacokinetic considerations 25 E. Structure-activity relations 26
V. Use of Animal Models to Assess Human Risk 27 VI. Recent History of Teratology and Evolution of Methods of Testing for Evaluating Devel-
opment 29 A. Alternative testing methods 35
VII. Uses of Teratological Data by Governmental Agencies 37 VIII. Evaluation of Human Risk 39
References 45
I. INTRODUCTION Congenital malformations or birth defects are a major public health concern. In this country, birth defects occur in a frequency of 20:1000 to 30:1000 livebirths, and an additional 60:1000 to 70: 1000 are observed in the interval between birth and 1 year of age (Hook, 1981). In 1995, this translated into 411 babies with birth defects of almost 11,000 born every day; 18 of these die every day as a result of a birth defect.* Minor anomalies represent another 140:1000 (Hook, 1981), and minor to severe mental retardation accounts for 0.7-0.8% incidence (Rosenberg, 1984). Congenital malformations account for approximately 14% of all infant deaths (Warkany, 1957). Birth defects
* National Center for Health Statistics, 1995.
