A Brief Introduction to Prenatal Development
Prenatal development is one of the most significant
segments of our development. It is an extraordinary process to learn and
to acknowledge, as it emphasizes the many aspects most people tend to
overlook. This information directly relates to our self-understanding,
the mother who bore us, and the various joys and difficulties associated
in the course of our nine month internal development.
The Effects of Teratogens on Prenatal Development
A human being developing in a mother's womb is an
intricate process divided up into trimesters (three, three month
periods). Throughout these nine months, prenatal development is
constantly under strong influences, largely governed by genetics and
external factors. If a baby's development were regulated mainly by their
genetic composition, prenatal development would be more orderly and
precise. External factors, on the other hand, influence pregnancy either
positively or negatively. For instances, the amount of oxygen a fetus
receives is an external factor that exerts an influence on the baby's
growth, regardless of any genes the baby inherits. Providing appropriate
levels of oxygen allows the fetus to reach its full genetic potential
(Harding & Rees, 2004), which often determines how the child will
behave, perform, and respond after birth and later on in school.
Figure 1. Periods of Fetal
There are many external factors that negatively
impact both the fetus and the mother during pregnancy; some of which
cause permanent prenatal abnormalities. These broad range of substances,
known as teratogens, are readily found in almost any environment.
Teratogens can be airborne contaminants, such as harmful gases, vapours,
and pesticides; drugs and medication, such as cocaine, anticonvulsants,
and Thalidomide; congenital infections, such as human immunodeficiency
virus and syphilis (Table 1); consumption of alcohol; cigarette smoking,
radiation, and stress. With the availability of new tools such as
3-dimensional ultrasound and magnetic resonance imaging, it has been
shown that the critical period of organ and limb development occurs
within the first trimester - more specifically, the first eight weeks of
growth (Citen & Giorgio, 2006; Figure 1). Women who are exposed to high
doses or high levels of teratogens during this sensitive stage in
prenatal development can increase the risk of causing various mental and
physical complications in the baby; in most cases, these conditions are
irreversible. Figure 2 offers a startling example of apparent
neurological effects of pesticide poisoning on children caused by high
levels of exposure during pregnancy.
Table 1. A List of teratogens and
their effects on human health.
Figure 2. Elizabeth Guillette, an
anthropologist, was interested in the effects of pesticides on children.
She chose a study site in Yaqui Valley region in Mexico. When synthetic
pesticides arrived in the area in the 1940's, some Yaqui farmers
embraced the use of pesticides for agriculture, while others continued
to follow more traditional farming practices in the foothills area.
Although differing in farming techniques, the population shared the same
culture, diet, education system, income levels, and family structures.
When asked to draw people, young children from the foothills where
pesticides were not used drew recognizable figures, while children from
the valley where pesticides were heavily used could draw only scribbles.
Adapted from (Guillette et al., 1998).
A teacher can usually identify a normal student from
a student with physical abnormalities. For instance, students who have
fetal alcohol syndrome (FAS) have similar facial features, such as a
small non-symmetrical head, short nose, widely spaced eyes, thin upper
lip, and small ears (Figure 4). In addition to these physical
characteristics, a teacher can also identify a child with FAS, or its
milder form fetal alcohol effects (FAE), by noticing learning
disabilities, attention or memory deficits, inability to manage anger,
poor judgment, or difficulties solving problems. FAS occurs when a mother overly consumes alcohol during
pregnancy. When alcohol (a teratogen) crosses the placenta, it cannot be
removed by the liver since the liver of an embryo is not fully developed
until the last trimester; consequently, it depresses the function of the
fetuses nervous system (Campbell & Farrell, 2006). A teacher who is
aware of the normal responses associated with FAS/E students will
approach the child in a different manner and accurately interpret their
classroom behaviour, rather than responding in a way that may create a
more difficult situation. For instance, if an FAS student repeatedly
makes the same mistake of forgetting to complete his/her homework, a
knowledgeable teacher would take the initiative in making a personalized
checklist that the student can take home, as opposed to getting angry
and punishing the student unjustly. Knowledge about teratogens can help
the educator recognize that it is not the student's main intent to
purposely forget or misinterpreting the situation and blaming laziness
or poor parenting. Moreover, to improve a FAS/E student's poor judgment
and social skills in the classroom, a teacher can include the student as
often as possible, or have them work on activities that encourage
decision making by giving the student choices and allowing the student
to carry through with the choices they make (Teaching Students with FAS,
2006). To improve memory skills, a teacher can modify their lessons to
include many examples, making it easier for the student to learn and
retain the concept.
Figure 3. An ad depicting the
harmful effects of alcohol on prenatal development.
Figure 4. Physical characteristics
of a child affected with fetal alcohol syndrome.
Some abnormalities caused by a teratogen may be
difficult to detect at a young age. For instance, maternal diseases like
syphilis or the use of streptomycin (a teratogen) during pregnancy can
cause various degrees of deafness in a child (Biller et al.,
2006). Deafness is not a physical defect that is readily detected by
visual inspection. In the classroom, a student's inability to hear the
teacher can become a communication barrier; this, however, should not
mean that student cannot successfully participate in the regular school
program. A teacher who encourages interaction between students who have
hearing imparities with classmates who can hear normally, promotes a
social and interactive setting. In order to ensure a learner-friendly
classroom, a teacher may also modify the physical environment by
eliminating any unnecessary distractions causing loud noises, such a fan
or air-condition; this will help to improve concentration during class.
Above all, by acknowledging the effects of teratogens on prenatal
development, a teacher will have a better understanding of their
student's learning abilities, weaknesses, and their parents' perception,
and in turn, help to keep the classroom environment learner-friendly.