Pre natal development can be defined as the development of a baby from the fertilzation upto the delivery(life span in womb or uterus of mother)
Its divided into three stages,
1.germinal stage, from fertilization to the implantation of the zygote.
2.Embryonic stage,from 2nd week to 8th week of development.
3.Fetal stage,3rd week to the delivery of baby.
Study different developmental changes in each stage.
Environmental effect on baby.
Its considerd the enviroment of mother during this period of development(pre natal development)
1.health state of mother
2.nutrition of mother
3.Alcoholism(if a mother drinks)
etc.
This question is meticulously addressed in feldman.