Stages of Prenatal Development - Research Paper Example

Through the example of cigarette smoke, however, it can be seen that long term effects can be appreciated that effect mental health throughout life. Through an examination of prenatal development in comparison to studies on the effects of environmental factors, it can be seen that brain development has the potential for long term influences from actions taken by the mother. The stages of prenatal development can be broken down into three definitive and accepted stages of development. The first stage, the germinal stage, is the period of time it takes from fertilization until the time where implantation of the fertilized egg occurs to the wall of the uterus.

For several days, perhaps three to four days, the cells within the egg will begin to multiply and move around the uterus without any attachment. Within a week, the mass of cells will attach themselves to the uterine lining. At this time, pregnancy has been initiated. The second stage is called the embryonic stage and lasts until approximately the eighth week of pregnancy. This is the time when major organ systems will begin to form and the mass of cells, or zygote, will become an embryo. During the third week, the formation of the embryo will include a fold of ridges where the nervous system will develop.

This is called the neural tube. It is in the fourth week that the beginnings of the heart will form and start to beat (Nevid 329). The position of the child is within the amniotic sac in which protection is provided as well as the containment of the embryonic fluid. There are several purposes for this sac of fluid. One is to protect the embryo from any jarring movements that the mother might make that might injure the child without the cushion. The placenta allows for the mother and child to exchange fluids, nutrients and waste moving through the umbilical cord through the placenta so that neither blood streams are interchanged.

The last stage of the pregnancy, which begins around the ninth week until the birth of the child, is defined by the fetal stage, in which the identity of the growing entity is defined as a fetus and the formation of the child, the fingers, toes, and all the major systems have formed which will be in line with the end of the first trimester (Nevid 330). According to Butterworth and Harris “Where abnormal environmental (or genetic) obtain, the embryo may be forced down abnormal pathways at choice points in the epigenetic landscape, with resulting atypical development” (39).

An example of problems of an environmental nature that can effect a child within its development was shown by Schaas et al when they determined that a mother that is exposed to lead during the third trimester of pregnancy would lead to a child who is effected with decreased intellectual development. The findings of the study show that “third trimester lead exposure is a more powerful predictor of later child IQ” (795).Therefore, what a child is exposed to will have an effect on how the brain develops, which therefore suggests that prenatal environmental factors may have a significant effect on the psychological development, as well as the intellectual development.

However, the length of time in gestation seems to have no bearing on intellectual development, thus most likely has little effect on the psychological effect. Children with retarded gestations periods have been shown to have no less intellectual