Family Health History
Kelsey McLaughlin, PhD
A visit to a new doctor or specialist usually involves questions about your family's health history, including your siblings, parents and grandparents. When preparing for pregnancy, it is important to learn more about your family's health history, if possible.
Keep reading to learn why knowing about your family's health history is important for pregnant women.
What does family health history mean, exactly?
Our genes make us who we are. If you've heard the debate 'nature vs nurture', our genetic material makes up the 'nature' half of the argument. Let's first talk about how our family history and the genetic material we inherit from previous generations can impact our health.
Scientists have estimated that our bodies are made up of over 37 trillion cells. These cells have different purposes and perform different tasks. For example, the cells on the outside of our skin look and act differently than the cells in our brains.
How do these trillions of cells make us functioning adult humans? Through our genes and genetic material.
Babies are conceived when the father's sperm fertilizes the mother's egg - the egg and sperm contain genetic material from each respective parent. The baby is therefore a combination of genetic material from the mother and father, as well as the previous generations that have passed down their genetic material.
No matter how different the cells of our body are, they all contain the exact same genetic material. Every cell contains 23 pairs of chromosomes, or 46 chromosomes in total. In each pair of chromosomes, one chromosome is inherited from the mother and one chromosome is inherited from the father; this means that we inherit 23 chromosomes from each parent. These chromosomes each contain thousands of genes.
Genes contain an unbelievable amount of information known as DNA that dictates the structure and function of all the cells in our bodies. Our DNA makes our hair, skin and eyes certain colors. It also tells the proteins and cells of our bodies how to function.
The cells in our bodies are therefore a random combination of genes from our parents. Due to the unique combination of genes from our parents, we are not a clone of either parent, but inherit traits from each parent. Slight variations and combinations in our genes and DNA make us unique individuals.
Our family history and genetics can strongly influence our health and risk of developing some diseases.
Some diseases are hereditary, meaning that they can be passed down from generation to generation through genes. For example, some families are at higher risk of having high cholesterol levels in the blood (familial hypercholesterolemia) due to changes in specific genes found on chromosome 19 that changes the body's ability to process cholesterol. This gene is then passed down through the generations, leading to more members of the family having high cholesterol than normal, with more significant health effects.
Therefore, knowing the health history of our families can provide doctors with insight into your unique genetic material and give clues into your risks for certain diseases, as well as the health of your baby.
How does family history impact your health during pregnancy?
If your family has a history of common health conditions, you could be at increased risk of pregnancy disorders.
As an example, let's focus on how our family health history can impact the development of hypertension in pregnancy, a common pregnancy disorder that impacts 10% of all pregnancies.
Women who have a parent or sibling with high blood pressure or diabetes are at increased risk of developing preeclampsia. We also know that women who develop high blood pressure in pregnancy are more likely to have a sister who also develops high blood pressure in pregnancy.
Scientists hypothesize that certain genes relating to how the placenta, blood vessels and heart functions that are inherited through your parents' genetic material may increase the risk of hypertension in pregnancy in some families.
Doctors will look for patterns of disease in your family to assess if there may be a genetic basis to some diseases. It may be helpful for your doctor to know about any significant family history of:
How does family history impact your baby's health?
In the same way that your genetic material inherited from your parents impacts your health and pregnancy health, the genetic material that your baby inherits impacts his or her health.
Screening tests can help to detect genetic abnormalities in the developing baby. These screening tests include prenatal blood tests and ultrasounds that are done early in pregnancy. Doctors can assess if the baby could have a chromosomal abnormality, such as Down syndrome, or developmental concerns. If the results from these screening tests indicates that there may be a genetic concern, women can undergo more definitive testing to make a formal diagnosis.
The most common condition caused by an abnormal level of chromosomes is Down Syndrome, also known as Trisomy 21, which impacts 1 in 800 babies. While the majority of humans have 2 copies of every chromosome (one from their mother, one from their father), those affected with Down Syndrome inherit 3 copies of Chromosome 21. Doctors can screen for Down Syndrome in pregnant women, then make the diagnosis with more thorough investigations. Other chromosomal conditions that are commonly screened for include Trisomy 18 (Edwards Syndrome) and Trisomy 13 (Patau Syndrome).
Risk factors for having a baby with a genetic disorder include:
Family history of genetic disorders
Genetic disorders in one of the parents
Parents have had a previous child with a genetic disorder
Other genetic diseases can involve the interaction of both the baby's genetic material and the environment. For example, several factors are linked to an increased risk of having a baby with neural tube defects, including a family history of this defect, low levels of folate in the mother's diet and geographic location.
Our family's health history can provide valuable information about our future pregnancy health and identify potential increased risk of fetal disease. Together with a genetic counsellor and other professionals, doctors can help to develop a plan for the healthiest pregnancy possible. Genetic counselling prior to pregnancy and screening tests during pregnancy may be useful for those who have a significant family history of health conditions, have had a child with a significant medical condition or have had difficulty conceiving.
Every woman and every pregnancy is unique. Pregnant women should speak to their healthcare provider to ensure maternal and fetal safety. This article is meant to provide readers with current information and opinions. All medical and treatment decisions should be discussed with your healthcare provider.