testing can be a multi-edged sword. Usually, test results are reassuring, which puts expectant
parents’ minds at ease. But some people argue that because birth defects are
rare, these tests in most cases cause undue stress;
others argue that they allow people to create “designer” children. Then there
are the parents who discover very real, sometimes dire, problems with their
babies and face the decision of whether to keep or terminate a pregnancy. Testing
is a difficult and confusing issue, and what’s right for one family may be
entirely wrong for another.
opt out altogether, claiming that even if a problem were detected, they would
never terminate a pregnancy. Others choose to undergo blood screening tests but
nothing invasive, such as amniocentesis. Still others say yes to every
procedure offered to them, wanting to gather as much information as possible
about the fetus’s health—and, hopefully, reduce their anxiety along the way.
a very sensitive issue, and a very personal one,” says Barbara M. O’Brien,
M.D., a geneticist and maternal-fetal medicine specialist at Women &
Infants Hospital in Providence, R.I. “Patients can feel pressured to opt into
screening, but they shouldn’t be. It’s a personal decision.”
can be so delicate that prospective parents should start considering it very
early, even when they begin planning a pregnancy. “The clock is ticking once
you conceive,” explains certified nurse-midwife Barbara L. McFarlin, Ph.D.,
C.N.M., of the department of women, children and family health science at the
University of Illinois at Chicago College of Nursing. “There are certain
windows when tests have to be completed.” Following are the most common
screening and diagnostic tests currently being given, along with a few other
types most moms-to-be have. But which you are offered, and which you choose to
undergo, may vary according to your age, where you live, your personal or
family history, and many other factors.
are offered a screening test in both the first and second trimesters. Your
results will come back as either “screen positive” or “screen negative,” along
with a specific risk. “A screening test will never give you a ‘yes’ or ‘no’
answer,” says genetic counselor Cathy Wicklund, M.S., C.G.C., director of the
graduate program in genetic counseling at Northwestern University in Chicago.
“All they can do is quantify risk.”
interprets risk differently based on her personality, her education level, even
the way information is presented to her. But perhaps most influential is her
life experience. “If you’re the one person who got struck by lightning, you’re
going to think that in a 1-in-100 risk scenario, you’re going to be that one,”
screening tests, diagnostic tests can confirm a birth defect exists by studying
tiny samples of a fetus’s genetic material. Approximately 5 percent of women
are referred for diagnostic tests following screening; O’Brien says the
incidence of diagnostic tests is decreasing because of improved screening
to the tests described here, you’ll likely undergo a urine test at each
prenatal visit to check for bacteria, which could signal a urinary-tract
infection, and protein, a potential preeclampsia symptom.
usually done at your first prenatal appointment to screen for certain diseases,
including STDs, and determine your blood type.
villus sampling (CVS)
will be older than 35 at delivery; those who have an abnormal first-trimester
screening test result.
OFFERED: At 10 to 12
syndrome and some other chromosomal defects.
WORKS: A small piece
of tissue is taken from the placenta via a tube inserted through the cervix or
a needle inserted through the uterine wall.
EFFECTIVE IT IS: Almost
100 percent. It poses a miscarriage risk of approximately 1 percent.
…? If a defect is
diagnosed, you’ll need to decide whether to continue the pregnancy.
OFFERED TO: All women.
OFFERED: At 10 to 13
SCREENS FOR: Chromosomal
defects such as Down syndrome and trisomy 18 (an often lethal defect); some
WORKS: Blood is drawn
from the mother, and three fetal proteins are measured. These results are
combined with the results of a detailed ultrasound (nuchal translucency) that
measures the thickness at the back of the fetus’s neck.
EFFECTIVE IT IS: It
has an 80 percent to 85 percent detection rate for Down syndrome, with a 4
percent to 6 percent false-positive rate.
WHAT IF …? If you have a positive screen and are
not comfortable with the odds, you may opt for a diagnostic test to determine
if your baby has a defect. Another option is to do an additional screen in the
second trimester—but this will not give you a definitive answer, either.
OFFERED TO: All women
(if it’s available in the area where she lives).
OFFERED: The first
part is conducted at weeks 10 to 13; the second part, at weeks 14 to 20.
SCREENS FOR: Down
WORKS: Results from
the first-trimester ultrasound and blood work are combined with the results
from second-trimester blood work.
EFFECTIVE IT IS: “It
has a very high detection rate for Down syndrome—85 percent to 90 percent—with
a very low false-positive rate: 1 percent to 2 percent,” O’Brien says.
…? If you do have a
positive screen, you’ll need to decide if you’ll have amniocentesis to confirm
the diagnosis (it’s too late for CVS).
OFFERED TO: All women.
OFFERED: At 14 to 20
SCREENS FOR: Down
syndrome, trisomy 18 and neural-tube defects (NTDs) such as spina bifida.
WORKS: Consists of a
blood test that typically looks at four different proteins in the mother’s
blood; often referred to as the “quad screen” or “multiple marker screening.”
Unlike first-trimester screening, second-trimester tests can screen for NTDs in
addition to chromosomal defects such as Down syndrome.
EFFECTIVE IT IS: It
has an 80 percent to 85 percent detection rate for Down syndrome, with a 7
percent false-positive rate.
…? If you have a
positive screen for any defect, you may choose to have an amniocentesis; a
level II ultrasound may also be offered.
OFFERED TO: Women who
will be older than 35 at delivery; those who have an abnormal first- or second-trimester
screening test result.
OFFERED: At 15 to 20
SCREENS FOR: Chromosomal defects such as Down syndrome; developmental defects such as NTDs.
WORKS: A small amount
of amniotic fluid is extracted via a needle inserted through the abdomen and
EFFECTIVE IT IS: Almost 100 percent. The risk of miscarriage from the procedure is approximately
1 in 200 to 1 in 600, depending on the skill and experience of the person
performing the procedure.
…? If a defect is
diagnosed, you’ll need to decide whether to continue the pregnancy or terminate
in-depth look at the screening and diagnostic tests you might undergo, and how
some real couples dealt with the decisions and emotional issues involved.
OFFERED TO: All women.
OFFERED: At about 20
weeks (also offered as part of the first-trimester screening).
SCREENS FOR: A wide
variety of problems. “An anatomical survey of the entire fetus is typically
conducted,” explains midwife Barbara McFarlin.
WORKS: Using a
transducer placed over the abdomen, sound waves create pictures of the fetus.
EFFECTIVE IT IS: McFarlin says it detects approximately 50 percent of heart defects; O’Brien
says it’s excellent at detecting NTDs. However, O’Brien adds: “Fifty percent of
babies born with Down syndrome had normal ultrasound results.”
…? If ultrasound does
detect a potential problem, you’ll need to decide if you want an amnio to
determine whether it could be part of a chromosomal or genetic syndrome.
This test is
done at weeks 26 to 28 to check for gestational diabetes (high blood sugar
during pregnancy), which increases the risk of having a too-large baby and
needing a C-section.
At 36 weeks
or so, you’ll be tested for the presence of potentially dangerous bacteria that
could be passed to the baby during delivery. It involves a painless swab of
your rectum and vagina.
consider Perhaps the
biggest issue surrounding prenatal testing is what you would do if a problem
were detected. “Women think they have to terminate, but that’s not true,”
McFarlin says. “You can continue the pregnancy and use that time to educate
yourself about the baby’s condition, talk to other families dealing with the
same issue, maybe even prepare for the delivery.” For instance, if the baby
will need surgery for a heart malformation at birth, you can find a hospital
with that capability and deliver there.
involves many such big decisions—ones that your doctor may not be able to
discuss at length. “A discussion about prenatal testing can take up to an hour,
time that many doctors just don’t have,” O’Brien says, adding that knowing all
the details of the various tests may not even be within their area of
expertise. As a result, many doctors routinely refer patients to a genetic
counselor, who specializes in this area. One important note: If a diagnostic
test indicates a problem, get a second opinion from a perinatal (high-risk)
NOT TO TEST
feel like knowing about a problem before you have the child and can do anything
is torture.” Even
though she was going to be 39 when her baby was born, Liz Lane and her husband,
Brent, decided at the outset that they wouldn’t do any prenatal testing. Not
only were they confident that they would not terminate a pregnancy under any
circumstances, but Liz felt that if they did find out about a problem, her
pregnancy would be marred by sadness and stress.
advised the San Diego-area couple to meet with a genetic counselor to discuss
their risks, but they decided against this, too. They did, however, have an
ultrasound. “We wanted to find out the gender, and the doctor wanted to check
on same basic things, such as whether the cord was wrapped around the baby’s
neck,” Liz says. “But I told him that if he found a genetic or other problem,
we didn’t want to know.”
did tell the Lanes that if he were to detect a problem that would require
special care after delivery, he would be beholden to let them know. But he
found nothing wrong, and baby Robin was born full term, in perfect health, in
was very scary, and we immediately starting having this
what-will-we-do-if-there’s-something-wrong talk.”Northern California couple Sheila and
Ethan Cooperman (not their real names) were expecting their first child, and
they decided to have an amniocentesis at 16 weeks because of Sheila’s age, 35.
“The doctor called 2 1⁄2 weeks after the test and told us there was an abnormal
test result and we needed to come in to discuss it,” Sheila says.
Coopermans were told that a genetic mutation had occurred in about 15 percent
of the baby’s cells, yet it couldn’t be determined how severe any effects would
be. “We knew something had gone wrong, but we didn’t know what,” Sheila says.
“If the cells affected were in the brain, the baby could be severely retarded.
If they were in the elbow, the baby could have a big mole.”
other diagnostic tests were available, Sheila and Ethan opted to have a
detailed ultrasound. While waiting for the appointment, they started doing some
serious soul-searching. “Those three days were hell,” Sheila recalls. “We had
to have discussions like what if the baby has one arm and two legs? No arms and
no legs? Mental retardation?” The couple eventually decided that if they
thought their child had a chance at happiness, they would continue the
ultrasound showed no obvious defects, and today their daughter Renee is 13 and
completely healthy. The couple always have a bit of fear hanging over their
heads about what might unfold in the future. “But when Renee was born, we vowed
that we would rejoice in normal,” Sheila says. “If she had tantrums, if she was
an average student, whatever: Hallelujah!”
was incredibly difficult for both of us, but we felt the only thing we could do
was terminate.” Rhonda Berg, then 32
and pregnant with her first child, had a screening test at 16 weeks, and the
results indicated that the baby had a slightly elevated risk of a neural-tube
defect. Even though he assured her that everything was probably just fine, her
doctor recommended that she get an ultrasound and an amnio.
ultrasound the next day, Rhonda and her husband, Alex, who live in
Pennsylvania, met with a genetic counselor; she also was reassuring. But the
reassurance was short-lived. “The perinatologist became very quiet as he did
the ultrasound,” Rhonda says. “Then he switched off the machine, took a deep
breath and told us that he was sorry, but the baby had a very bad defect of the
shaking and crying,” Rhonda recalls. “Alex tried to comfort me, but what could
he do?” An amniocentesis confirmed that the baby had severe spina bifida, with
significant brain involvement as well. “We felt the only thing we could do was
terminate, but it was such a terrible, heartbreaking decision,” Rhonda says.
It took two
years before the Bergs felt ready to try for another baby, and for several
months beforehand, Rhonda took very high doses of folic acid daily. “I was so
scared to have an ultrasound during that pregnancy,” she says. “But the doctor
knew our history and was grinning from ear to ear when he told us our baby was
just fine.” Happily, the Bergs had a healthy son 12 years ago, followed by
healthy twins nine years later.