Prenatal testing is a complex, 'intensely personal' decision

 
 

By Robyn Monaghan

Contributor
 

When Sheila Quirke woke up that morning, she knew July 18 could be her best day, a bad day or the absolute worst day of her life.

The Quirkes were expecting results from two sets of medical tests that would foretell the fate of their 2-year-old daughter, Donna, and their unborn son. An MRI would tell if Donna's cancerous brain tumor was growing back and amniocentesis would predict if the tiny embryo growing inside Sheila would be born with Down syndrome.

Who should have prenatal testing?

  • Women 35 or older who are pregnant or are planning to become pregnant
  • Abnormal ultrasound findings
  • Couples who are close blood relatives, such as first cousins
  • Women who have a condition, such as diabetes, that can be associated with an increased risk of fetal problems
  • Unexplained or multiple miscarriages
  • Family history of an inherited condition or birth defects
  • Positive maternal serum screening, such as AFP Tetra

Source: March of Dimes

"Having the information that the baby was healthy in the womb helped us cope with our daughter's relapse," says Quirke, 39, a social worker and city ombudsman for West Ridge.

Quirke and her husband, Jeremy Hornik, had no doubt that, for them, the advantages of prenatal testing far outweighed the dangers.

"Most parents don't confront their worst fear-that something could be wrong with their baby," Quirke says. "But once you have a child with cancer, you realize that things can and do go wrong."

Window of time

That doesn't mean it was an easy call. To test or not to test is a complex equation of morals, medical terms, mom's age and miscarriage risk factors. Often, it's a life-or-death decision parents have to make on the guidance of an hour's counseling and a narrow window of time to make up their minds.

"Time is an issue," says Katherine Kim, a genetic counselor at Children's Memorial Hospital in Chicago. "There's a very limited time to consider the options, weigh the risks and decide what you'll do either way in just a matter of days."

In her role as genetics counselor, Kim is the person who helps parents sort out the pros and cons of prenatal testing. Among the overwhelming amount of information she needs to impart to parents is that they can terminate a pregnancy under 24 weeks in Illinois and test results can take as long as a month to be processed.

There's little lead time to resolve a long list of issues, local genetics and prenatal counselors say. What are the risks? How much do you trust the results? What will you do if you find out there is a problem? Will knowing the baby may have a disability make it easier to plan for infant care once it is born?

Questions to consider

  • Is the information I'm likely to get from prenatal testing worth taking the risk?
  • Would test results affect my decision to continue the pregnancy?
  • Will I be able to enjoy my pregnancy without the prenatal test results?
  • Do I need the information from prenatal testing to prepare in advance and educate myself about my baby's condition?

Source: Katherine Kim, genetics counselor at Children's Memorial Hospital

Do the math

In some cases, the conclusion can boil down to simply doing the math, finding a bottom line by comparing the risks of birth complications with the risk of the tests, Kim says. The two most definitive prenatal tests-amniocentesis and chorionic villus testing-come with a risk.

In Sheila Quirke's, case, for example, a blood test put her chance of delivering a baby with Down syndrome at about one in 50. The risk of the test causing a miscarriage was about 1 in 800 to 1,000.

If only it were that simple to make a decision.

"Once you have one child with a genetic condition, numbers lose meaning," Kim says. "Parents just feel either it will happen or it won't."

Beyond figures and fractions

But lurking among objective factors like figures and fractions are subjective qualifiers like ethics, family history and even finances.

"It's not just about a medical diagnosis," says Dr. Barbara Burton, a professor of pediatrics in the division of genetics, birth defects and metabolism at Children's Memorial Hospital.

Of course, the most grueling choices hinge on whether parents will continue a pregnancy when tests show the embryo has a health problem.

"If parents feel like they're not going to gain any benefit from the test, knowing that they're never going to change their decision to continue the pregnancy anyway, why take the risk that comes with some tests?" Burton asks.

But there are reasons to assume that risk. Some conditions considered fatal can be successfully treated with stem cell therapy in the first weeks of life, Burton says. Knowing about a genetic condition before birth also gives families time to educate themselves, gather resources and put a support system in place before the baby arrives.

For parents who already have one child with a medical problem or disability, knowing the one they are carrying now is healthy can be an advantage in promoting a positive pregnancy. That's how it worked for Quirke.

"Once I found out the baby in my womb was able to take care of itself, I could use my energy to take care of myself and to take care of Donna," she says.

No wrong answers

Quirke got a lot of unsolicited feedback from friends and family members about her decision to go for the amniocentesis. Why did she want to know? What was the point? Was she considering not going through with the pregnancy if the results weren't good?

"I don't confess to know if the amniocentesis came back positive for Down's how we would have responded. We didn't touch that question. We just took it one day at a time," she says. "But I know that for a lot of couples this is a wrenching decision."

As experts in prenatal testing, both Burton and Kim stress their job is to educate and get people thinking. No one can tell parents whether prenatal testing is for them, they say.

"It's an intensely individual and personal decision," Burton says.

Kim adds: "But there are no right or wrong answers to this kind of question."

Types of genetic prenatal tests


Screening tests

Cannot diagnose a birth defect, but only determine if the fetus has a high or low risk for a particular problem. One example is a maternal blood test that identifies pregnancies at increased risk for open neural tube defects, Down syndrome and trisomy 18.

Diagnostic tests

Can diagnose certain fetal problems with a high degree of accuracy. Amniocentesis, a prenatal diagnostic test performed on amniotic fluid, identifies fetal chromosome abnormalities. If, for example, an extra chromosome 21 is seen, a diagnosis of Down syndrome is made.

Chorionic villus sampling

What: Used to diagnose chromosome abnormalities, some inherited disorders and certain birth defects in a fetus.

Who: Mostly for women over 35 or who may have an inherited genetic problem that can be diagnosed.

How: A thin needle is either inserted through the abdomen or a specially designed catheter is passed through the vagina and a piece of placenta, about the size of a few grains of rice, is removed.

Risk: The risk of miscarriage or serious complication is 1/200 to 1/100.

Amniocentesis

What: Used to diagnose fetal chromosome problems such as open spina bifida, abdominal wall defects and some inherited problems.

Who: Women in their second trimester.

How: A thin needle is inserted through the mother's abdomen into the amniotic sac and a small amount of amniotic fluid is removed.

Risk: Increases the risk of miscarriage by about 1/200.


Source: March of Dimes

 
 







 
 
 
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