Prenatal Testing: Facts, Types, Pros & Cons

Prenatal tests can be confusing and scary, so why should you opt to do them?

Prenatal tests can provide valuable information about the baby and mother’s health. There are two types of prenatal tests: genetic screening and genetic testing. Administered between the 10th and 13th week of pregnancy, prenatal tests can help a physician decide what advice to give the pregnant mother, medication to prescribe or prohibit, and other treatments to administer.

Genetic screening involves measuring a level of risk for a genetic condition in the fetus. Screening tests assess the degree of risk, or chance, that the fetus may potentially have common birth defects. However, they cannot tell with certainty if the baby actually has the condition, according to The American College of Obstetricians and Gynecologists.

Diagnostic or genetic testing can actually detect many genetic conditions caused by chromosome abnormalities. They usually can tell prospective parents whether or not their baby has a particular genetic condition.

The basic prenatal tests are:

Blood Tests: These tests are used to find out the blood type, rhesus factor, glucose level, iron, and hemoglobin levels. Blood tests are also used to check for STIs, rubella (German measles) and chickenpox immunity, and toxoplasmosis.

Pelvic Exam: This involves taking a pap smear to screen for cervical cancer. Samples are taken to detect STDs. A bimanual internal exam will also be performed to check the size of the uterus and pelvis, and check for abnormalities in the uterus, ovaries, and fallopian tubes

Physical Examination: The mother’s breasts, heart, lungs, and blood pressure will be checked.

Glucose Tolerance Test: This is used to diagnose gestational diabetes in pregnant women. A Glucose Challenge Screening is first performed, and, if the woman tests positive for it, the Glucose Tolerance Test is then performed.

Alpha Fetoprotein Test: This screening test is used to tell whether there is risk of baby having spina bifida, anencephaly, and other congenital defects. It’s usually done between the 15th and 20th week.

Ultrasound: Using high-frequency sound waves, the ultrasound captures an image (sonogram) of the baby and placenta and scans the woman’s pelvic cavity and abdomen. There are different kinds of ultrasounds performed at different stages of the pregnancy. Some are standard ultrasound, advanced ultrasound, transvaginal scan, Doppler ultrasound, 3d ultrasound, and fetal echocardiography.

Nuchal Translucency Ultrasound: It’s used to determine a  baby’s risk or potential for having Down’s Syndrome or other chromosomal abnormalities and is performed sometime between the 11th to 14th week.

Chorionic Villus Sampling: This is a diagnostic test used to determine chromosomal or genetic defects in the fetus. It is done by collecting material from the placenta using a thin catheter or needle that’s passed through the cervix to draw out the sample of tissue. It is performed 10-13th weeks from the last menstrual period. It’s important to know that there is a risk of a miscarriage and of the baby developing a limb or digit deficiency after CVS is performed.

Cystic Fibrosis Screen: This is one of the early prenatal tests done. It’s usually performed on both the mother and her partner to determine if either of them are CF gene carriers. If both partners test positive for the gene, further testing will be done to find out the risk of the baby having cystic fibrosis.

Triple Screen Test: This test is used to check for the levels of three specific substances— alpha fetoprotein, hCG (human chorionic gonadotropin), and estriol. It is a non-invasive procedure performed through a blood test. It’s also used to discover if the pregnancy carries multiple babies and if it is more or less advanced than was originally thought.

Quad Screen Test: This is very similar to the Triple Screen Test, except that it looks for a fourth substance called Inhibin-A.

Urinalysis: Urine tests are performed regularly throughout pregnancy. They are used to assess possible bladder or kidney infections, preeclampsia, dehydration, and diabetes.

Amniocentesis: This test is used to check for genetic, chromosomal, and neural tube defects in the fetus and is 98%-99% accurate. It’s performed 15-18 weeks into the pregnancy. Miscarriage is a risk associated with undergoing amniocentesis.

The most obvious benefit for undergoing genetic screening is that the family obtains the information about the possibility of any predispositions for genetic conditions. Because of this the family can determine what is the best way to proceed with this information. This can include anything from taking precautions with specialist doctors to taking different prenatal vitamins. If a genetic screening gives information on chromosomal abnormalities in the fetus, a genetic diagnostic test is recommended to ensure that the genetic screening did not give a false positive. Genetic screenings can give false positive results and can lead parents to believe that their unborn child has genetic abnormalities that they actually do not.

The benefits to partaking in the genetic testing or diagnostic testing is that knowing the information in advance can help parents prepare themselves for a baby that may have special needs. However, these tests do slightly increase the risk of miscarriage and other pregnancy complications.

Genetic screening can predict the likelihood that your child will be develop a genetic condition. If you already know your child is predisposed or may suspect it, you should look into umbilical cord blood banking. Many of these genetic conditions can be treated now or are undergoing research for treatment with umbilical cord blood and tissue. If your child is predisposed to have a certain genetic condition that can be treated with umbilical cord blood, you may be able to use your Flexible Spending Account to use nontaxable funds to pay for private umbilical cord blood banking. For more information on if you qualify for an FSA compensation of private cord blood banking, please speak to your doctor and insurance company.

If you are interested in cord blood banking, we would be happy to help you learn more and find the right options for your growing family. Schedule your free cord blood consultation now.

Sources:

•  “Prenatal Genetic Screening Tests: Benefits & Risks”. LiveScience.  
•  “Benefits of prenatal testing”. American Pregnancy Association. 
•  “Your Guide to Prenatal Testing”. WebMD. 
•  CDC: Chorionic Villus Sampling and Amniocentesis: Recommendations for Prenatal Counseling
• Cystic fibrosis: prenatal screening and diagnosis. (n.d.). ACOG.

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