Genetic Testing Before & During Pregnancy: Guide For Parent

Have you ever wondered if there’s a way to know about your baby’s health before they’re even born? Expecting parents often carry this concern, especially when they have a family history of genetic disorders.

Unfortunately, many genetic conditions can remain undetected until it’s too late to take preventive steps. In India, over 1.7 million 1 children are born each year with birth defects, many of which are linked to genetic factors. Thankfully, advances in genetic testing before and during pregnancy help parents with the tools to assess the risk of inherited conditions early on.

Why Genetic Testing Matters for Pregnancy

Genetic testing during pregnancy is essential because it allows you to detect potential health risks in your unborn child. It can also uncover if you or your partner carry genetic mutations that might cause disorders in your baby. This information can help you take early steps to either manage or, in some cases, prevent certain conditions.

From disorders like Down syndrome to cystic fibrosis, early detection enables timely medical interventions, personalised treatment plans, or decisions about further testing. The testing is not only beneficial for those with a family history of genetic conditions but also for every expecting parent who wants to ensure the healthiest start for their child.

Genetic Testing Before Pregnancy (Preconception Testing)

Some genetic testing before pregnancy can help you understand whether you or your partner carry any genetic disorders that might affect your future child. Standard preconception tests include:

Carrier Screening: This test looks for genetic mutations that you can possibly pass to your child. Conditions like cystic fibrosis, sickle cell anaemia, and thalassemia can be detected through carrier screening. For most conditions to affect the child, both parents must be carriers of the same mutation.
Expanded Carrier Screening: This is a more comprehensive form of carrier screening that checks for hundreds of genetic conditions. It’s particularly helpful for people from populations with a higher prevalence of certain conditions, like beta thalassemia.
Genetic Counseling: Genetic counselling accompanies preconception testing, where a genetic counsellor helps you understand the risks and implications of the test results. It provides a clearer perspective on your chances of passing on a hereditary disorder to your future child and helps you make an informed choice about pregnancy.

Benefits of Preconception Testing

Preconception testing offers several advantages for those planning a family:

Better Family Planning: By knowing your carrier status in advance, you have the chance to explore different options like IVF with preimplantation genetic testing or adoption.
Reduce Risk of Inherited Disorders: If both parents are carriers of a genetic condition, specific IVF methods or prenatal tests can help reduce the chances of the disorder affecting your child and reduce the risk of genetic disorders.

Limitations of Preconception Testing

While preconception screening is undoubtedly beneficial, it comes with a few limitations:

Limited Scope: These tests usually cover common genetic disorders, so rare conditions might not be detected during routine screening.
Emotional Impact: Finding out that both partners carry a genetic mutation can be stressful while planning future pregnancies.

Genetic Testing During Pregnancy (Prenatal Testing)

Once a pregnancy is confirmed, prenatal genetic testing can provide more exhaustive information about the baby’s health. Some of the most common types of genetic screening tests done during pregnancy are as follows:

Non-Invasive Prenatal Testing (NIPT): NIPT blood test analyses small amounts of fetal DNA circulating in the mother’s blood. This non-invasive prenatal test screens for chromosomal disorders like Down syndrome, Edwards syndrome, and Patau syndrome as early as the 10th week of pregnancy.
Ultrasound: Along with NIPT, an ultrasound can provide clues to possible genetic disorders by detecting physical anomalies or abnormalities in the baby’s development.

The following diagnostic tests provide more detailed genetic information when needed:

Quantitative Fluorescence Polymerase Chain Reaction (QF-PCR): This rapid test identifies specific chromosomal abnormalities, including Down syndrome, Edwards syndrome, and Patau syndrome. It’s commonly recommended for women with high-risk pregnancies to screen for common aneuploidies.
Fluorescence In Situ Hybridization (FISH): FISH is a prenatal screening method that uses fluorescent probes to detect and locate specific DNA sequences on chromosomes. This test is often used when there’s an increased risk of chromosomal abnormalities and provides faster results for conditions like trisomies.
Multiplex Ligation-dependent Probe Amplification (MLPA): MLPA helps identify various genetic disorders by detecting changes in DNA, such as duplications or deletions of specific chromosome regions. This test can be beneficial in cases where there’s a history of genetic conditions.
Chromosomal Microarray Analysis (CMA): This advanced test can detect small chromosomal changes that may not appear in traditional karyotyping. It’s especially useful for identifying genetic abnormalities in cases where other tests have been inconclusive.
Low Pass Whole Genome Sequencing (LPWGS): LPWGS is a cost-effective method that provides a comprehensive view of the genome, helping identify copy number variations (CNVs) and structural variants that could indicate genetic disorders. It offers broad coverage and can be useful when other tests do not provide adequate information.
Exome Sequencing: This sequencing approach analyses all protein-coding regions of the genes, helping detect rare genetic mutations. It’s recommended for cases where standard prenatal screening may not provide adequate information.
Sanger Sequencing: Known for its accuracy, Sanger sequencing is used to confirm specific gene mutations identified by other screening tests. It’s often recommended when there’s a known familial genetic mutation that could be passed to the baby.

Benefits of Genetic Testing During Pregnancy

Genetic screening during pregnancy comes with several advantages, which are as follows:

Early Detection helps identify potential health issues in the baby early on, allowing parents to be better prepared emotionally and medically.
Better Medical Planning: Adequate information about the baby’s genetic condition enables your healthcare team to plan for any special care required at birth.
Improved Support Services: Identifying genetic conditions early can help parents access support services and resources, such as early intervention programs, counselling, and educational resources tailored to their child’s needs.

Limitations of Genetic Testing During Pregnancy

Despite its benefits, genetic screening tests during pregnancy also have certain limitations:

Risk of Invasive Testing: Some screening tests, like amniocentesis and CVS, may have a small risk of miscarriage.
Emotional Strain: Abnormal results can be overwhelming and may lead to difficult decisions regarding the pregnancy.
Possibility of False Results: No test is perfect; sometimes, false positives or negatives can occur, leading to unnecessary anxiety.

Conclusion

Genetic testing, whether before or during pregnancy, offers valuable insights into the health of your future child. From helping with family planning to detecting inherited conditions early, these tests empower you with knowledge that can guide important decisions. While these tests are beneficial, it’s essential to consult a healthcare professional to understand the limitations and choose the right tests based on your individual needs and family history. While genetic testing can provide clarity, it’s one of the many tools to ensure a healthy pregnancy and baby.

Take the next step for a healthy future with MedGenome’s reliable genetic testing services. Contact us today!