Fetal organogenesis

Treatment of rats with cypermethrin up to 8 mg/kg/day produced no malformations [140]. Maternally toxic dose level of bifenthrin did not produce adverse effects on embryonic development in rats [141], A rabbit teratology study with 30 or 90 mg/kg/day tetramethrin during fetal organogenesis demonstrated no adverse effects on skeletal or external development [137]. 

The more frequently prescribed drugs that have been reported to affect growth and function of organs when given to the mother after the period of fetal organogenesis, or to the newborn infant, are discussed below. 

Diethyl phthalate administered in the diet to rats during major organogenesis increased the incidence of fetal lumbar ribs only at 3200mg/kg/day, a maternally toxic dose. In another report, there also was an increased incidence of supernumerary ribs, but no other embryo/fetal effects, in the offspring of rats fed 5% DEP on gestational days 6-15 maternal toxicity was evident as reduced body weight gain. ... 

Fetal development promotes growth and differentiation of fetal cells and organogenesis Promotes longitudinal body growth and increased body weight Promotes enhanced functioning of the male and female reproductive tissue Promotes growth and differentiation of neuronal tissue... 

The objectives of a teratology study (see Note 2) are to evaluate the effects of the test item on embryonic and fetal development when administered during the period of organogenesis, i.e., from uterine implantation to the closure of the hard palate (see Note 3)... 

Fleeman TL, Cappon GD, Chapin RE et al (2005) Effects of feed restriction during organogenesis on embryo-fetal development in the rat. Birth Defects Res B Dev Reprod Toxicol 74 42 49... 

The embryo-fetal development study aims to detect adverse effects on pregnant females (i.e., maternal toxicity) and on the development of embryos and fetuses (i.e., embryo-fetal death, altered growth, and structural changes) consequent to exposure of the female during organogenesis. 

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