Hereditary and Environmental Influences on Childbearing

Hereditary and environmental factors influence a person’s development, even before conception. Hereditary factors refer to the genetic determination of traits, like eye color or the inheritance of disorders, like cystic fibrosis.

On the other hand, environmental factors refer to external influences found where people live, work, and play that can impact how genes are expressed.

Often, the impact on a person’s development is multifactorial, meaning it results from a combination of hereditary and environmental factors.The hereditary material that determines a person’s development is contained in their chromosomes.

Tightly packed into each chromosome is DNA, which is organized into genes that carry a person’s unique genetic code.During fertilization, each parent donates half their chromosomes to create a fertilized ovum, called a zygote, which contains a total of 46 chromosomes organized into 23 pairs.

These chromosome pairs are numbered from 1 to 22, with the 23rd pair, the sex chromosomes, labeled as X or Y.Now, if chromosomes are altered, the person’s development can be negatively affected.

These chromosomal alterations can involve changes in the structure of a chromosome, and can involve deletions, duplications, translocations, and inversions.

A deletion is when part of the DNA is missing, like with cri-du-chat syndrome, where the short arm of chromosome 5 is missing.

If there’s extra genetic material in a chromosome, it’s called duplication, like when there’s an extra copy of some of the genes found in the long arm of chromosome 7, resulting in developmental delay, behavioral problems, and other anomalies.

Another structural alteration is translocation, where part of a chromosome moves to another chromosome. An example is the Philadelphia chromosome, which is chromosome 22 with a bit of chromosome 9 on it, resulting in a type of leukemia.

Lastly, an inversion, which is where part of a chromosome is rearranged in reverse order. Inversions often result in spontaneous abortions or infertility.There are also chromosomal alterations that involve changes in the number of chromosomes.

Monosomy can happen if one of the chromosomes in a pair is missing, trisomy is when an extra chromosome is added to a pair.

An example is trisomy 21, where there are three copies of the 21st chromosome, resulting in Down syndrome. A trisomy can happen with sex chromosomes, too.

So, in Klinefelter syndrome, there’s an extra X chromosome, or XXY, where the affected person is genetically male, but hypogonadism, or underdeveloped genitals, testosterone deficiency, and infertility are also present.As far as environmental influences go, these can involve teratogens, which are harmful agents that can alter the environment in such a way that a defect occurs.

Teratogens can be infectious, like rubella, varicella, and toxoplasmosis; medications, like folic acid antagonists, lithium, and antihyperlipidemic agents; substances, like alcohol, tobacco, and illicit drugs; as well as herbicides, lead, or mercury.Now, genetic counseling can provide parents with support through information, advocacy, and referrals for specialty services.

The counseling can occur before, during, or after pregnancy. Before pregnancy, preconception screening involves an evaluation of family history by evaluating medical records, using photographs, or by constructing a genogram, which can help identify inheritance patterns in family members.

After conception, prenatal testing typically involves identifying fetal abnormalities through diagnostics, like maternal blood tests, ultrasonography, amniocentesis, or chorionic villus sampling.

If a baby is born with a defect, then postnatal testing can include physical examination and imaging, and blood tests can detect inherited disorders like sickle cell disease or cystic fibrosis.

Chromosomal analysis can also be done, where the number of chromosomes can be counted and examined for structural abnormalities.As the nurse, your interventions will focus on identifying factors that indicate the need for genetic counseling.

While gathering your patient’s medical history, you can note if their occupation increases the risk of exposure to teratogenic agents, or if they're being treated with medications that are teratogenic.

You'll also check if they’re at risk of contracting an infection that can be harmful during pregnancy, and ensure they are up to date on their immunizations.

In addition, you can provide counseling about lifestyle modifications that can impact inheritance like diet, smoking, or alcohol use.Other interventions include taking a detailed family history and constructing a three-generation genogram to identify any genetic risk factors that would warrant professional genetic counseling.

Finally, if your patient’s genetic testing reveals abnormal results, you can support them by providing education, resources, and emotional support, as needed.Alright, as a quick recap...Hereditary and environmental influences can affect a person’s development, even before conception.

Development can be negatively affected by changes in the structure or number of chromosomes or exposure to teratogens. Nursing considerations are focused on identifying factors that indicate the need for genetic counseling.