Posts Tagged ‘CVS’

Is it a boy or a girl?

Friday, August 26th, 2016

its-a-girl-storkFinding out the sex of your baby is such an exciting part of pregnancy. While some people choose to be surprised at the time of delivery, many couples want to know the sex of the baby before they give birth. its-a-boy-stork

XX or XY

Your baby’s sex is determined at the moment of conception.  Of the 46 chromosomes that make up your baby’s genetic material, two chromosomes–one from the egg and one from the sperm–determine your baby’s gender.  A woman’s egg contains only X sex chromosomes.  A man’s sperm, however, may contain either an X or Y sex chromosome.  If, at the instant of fertilization, a sperm with an X sex chromosome meets the egg (another X chromosome), your baby will be a girl (XX).  If a sperm containing a Y sex chromosome meets the egg, your baby will be a boy (XY).  It is always the father’s genetic contribution that determines the sex of the baby.

How can I find out the sex of my baby?

Most women find out their baby’s sex during a routine ultrasound in the second trimester—usually between 18-20 weeks.  Traditional ultrasound is approximately 93% to 100% accurate at detecting the baby’s sex. But, just remember that sometimes the sex is not clearly identifiable from an ultrasound. This is usually due to the position of the baby.

While ultrasound is accurate, if you want to be absolutely certain of your baby’s sex, you would need a diagnostic test, such as a CVS (done between 10-12 weeks of pregnancy) or amniocentesis (done between 15-20 weeks of pregnancy). It is important to keep in mind that these prenatal tests are invasive and are done primarily to diagnose certain genetic conditions, such as Down syndrome.

Another way you may find out if you are having a boy or a girl is through cell-free fetal DNA testing (also called noninvasive prenatal testing or NIPT). NIPT tests your blood for your baby’s DNA to see if he may have certain genetic conditions, like Down syndrome. While this test is not used specifically to determine the baby’s sex, it can provide that information. It can be done after 10 weeks of pregnancy.

Did you find out if you were having a boy or a girl? Did you reveal it in a special way? Let us know—we’d love to hear your stories!

Have questions? Email us at AskUs@marchofdimes.org.

Screening vs. diagnostic testing—what’s the difference?

Friday, June 26th, 2015

DoctorPregnant_zps3ac96800If you are pregnant, you know that every visit to your prenatal care provider involves a number of tests. At each prenatal checkup, your provider checks your weight, blood and urine. But in addition to these routine tests, you will also be offered prenatal tests that can assess your risk to have a baby with certain birth defects.

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women, regardless of age, be offered prenatal testing for Down syndrome and some other birth defects. There are two different types of tests that you can have: a screening test or a diagnostic test. It’s important to understand the difference between a screening test and a diagnostic test. Screening tests help evaluate the risk for certain birth defects, but they cannot diagnose a birth defect. Screening tests pose no risk to mother or baby. Diagnostic tests are highly accurate at diagnosing or ruling out specific birth defects. However, these tests may pose a very small risk of miscarriage.

Screening tests offered during pregnancy include:

  • Cell-free fetal DNA testing (also called noninvasive prenatal screening or testing): Some of your baby’s cells can be found in your blood. This test uses a sample of your blood to look at your baby’s DNA to check for certain genetic conditions. You can have this test after 10 weeks of pregnancy. This test is not recommended for women who aren’t likely to have a baby with a birth defect or who are pregnant with multiples.
  • First-trimester screening: Using a blood sample and ultrasound measurements, first-trimester screening can tell you if your baby is at risk for some birth defects, like Down syndrome. It is usually done between 11 to 13 weeks of pregnancy.
  • Maternal blood screening: This test measures four substances in your blood to determine the chance that a woman has a baby with certain birth defects like Down syndrome and neural tube defects. The test is done between 15 to 20 weeks of pregnancy.

Diagnostic tests are done by obtaining samples of your baby’s actual cells and therefore are more invasive. Diagnostic testing can detect most birth defects caused by a change in the number or shape of chromosomes. And testing for many inherited disorders can be done as well. However, not all birth defects can be detected.

Some women may choose to have diagnostic testing done instead of screening tests based on their age or family history. Other women may choose to start with a screening test and then, depending on the results, decide whether to have a diagnostic test. Prenatal diagnostic tests do carry a small risk of miscarriage (about 1 in 300-500).

  • Chorionic villus sampling (also called CVS): During this procedure, the doctor removes a small sample of tissue from the placenta. This can either be done transvaginally or transabdominally. You can get CVS at 10 to 12 weeks of pregnancy.
  • Amniocentesis (also called amnio): Your health care provider will use a needle to remove a small amount of amniotic fluid. Amnio is done between 15 to20 weeks of pregnancy.

Remember, all of these tests are optional. Make sure that you discuss your questions and concerns with your health care provider.

Questions? Send them to AskUs@marchofdimes.org.

 

Chat on genetic counseling

Monday, March 4th, 2013

Susan Klugman, MDEver wonder if genetic counseling is for you? Join us for a #pregnancychat on genetic counseling and why it’s important. Dr. Susan Klugman, Director of Reproductive Genetics at Montefiore Medical Center, will be our guest to answer your questions, such as: What ethnic groups are more at risk for a genetic disorder? What does a family health history entail? Which prenatal tests are right for you? and more.

Dr. Klugman is a “medical detective” who works to identify the possible genetic risk factors for many inherited diseases. She encourages couples to consider genetic testing even before they get married so they can be as informed as possible when planning their families. She serves on the Board of Directors of the New York State Genetics Task Force. 

Dr. Klugman has appeared on many broadcast media outlets including ABC World News Tonight with Diane Sawyer. Take this unique opportunity to learn from her and ask questions. Join us on Twitter Wednesday, March 6th at 1 PM. Don’t forget to use #pregnancychat to make sure we see your questions.

New prenatal blood test

Thursday, December 13th, 2012

New prenatal tests can give some parents piece of mind that the baby they’re expecting doesn’t have a disorder.  The tests are given sooner and with greater accuracy and less risk of miscarriage than current tests.

The new tests, which use fetal DNA suspended in the mother’s blood, can test for chromosomal disorders such as Down syndrome (trisomy 21) and trisomy 18, and Rh blood incompatibility. They also can determine the baby’s gender, which allows health care providers to screen for disorders such as hemophilia.

During pregnancy, fetal cells and cell-free fetal genetic material circulate in the mother’s bloodstream.  This DNA can be used to screen for certain genetic disorders without having to perform invasive procedures such as amniocentesis or CVS (chorionic villus sampling).

At present four widely used procedures assist health care providers in prenatal diagnosis. They are:
Amniocentesis: a procedure that collects some of the amniotic fluid that surrounds the fetus for analysis. This is a diagnostic test.
Chorionic villus sampling (CVS): a procedure that obtains tissue from around the placenta. This is a diagnostic test.
• Maternal blood tests: screening tests that use mother’s blood to help identify problems with the fetal brain, spinal cord, intestines or chromosomes. These tests include alpha-fetoprotein (AFP), hCG and other hormones. As with all forms of screening, abnormal results require follow-up testing to make a diagnosis.
Ultrasound: a scan using sound waves to visualize the fetus.

Cell-free DNA methods of screening are a new option. “Prenatal diagnosis gives parents important information about the health of their baby and the status of their pregnancy. More often than not, prenatal screening reassures parents that their baby is healthy and that these disorders are not present,” says Joe Leigh Simpson, MD, March of Dimes senior vice president for Research and Global Programs.  “For a high-risk infant, prenatal diagnosis gives parents and health care providers options that may include planning for a health problem or arranging for delivery in a medically appropriate setting. The first step toward treating these problems is diagnosing them, and cell-free DNA methods, without the need for invasive measures, are welcomed.”

Dr. Lee P. Shulman of Northwestern University says, “while this represents a profound improvement in our ability to identify women at increased risk for carrying fetuses with the most common chromosome abnormalities, still, this technology represents a limited screening protocol and should not serve as a substitute for diagnostic tests such as chorionic villus sampling and amniocentesis, which provide the most accurate and comprehensive assessment by the direct analysis of fetal tissue.”

The American College of Obstetricians and Gynecologists and the American College of Medical Genetics recommend that information on prenatal genetic screening and diagnosis should be made available to all pregnant women and those considering pregnancy.

With all the above options for testing available, it’s important to discuss what is best for you and your pregnancy with your health care provider.

To know or not to know

Thursday, March 29th, 2012

its-a-boy-storkits-a-girl-storkA while ago, someone wrote in to the March of Dimes with a wonderful idea. She was pregnant, and was on her way to the doctor’s office for an ultrasound where the sex of her baby would most likely be revealed. However, she and her husband were not yet ready to know if it was going to be a girl or boy.  But, they would want to know sometime before the baby was born…just not that day. Also, they had envisioned that the day they learned the sex of their baby would be somewhat more special, and not something that would occur in a doctor’s office. So, they came up with this novel idea that I thought was worth sharing.

They suggest you have the ultrasound tech or doctor write the gender of the baby on a piece of paper, and seal it in an envelope.  Then, on a special occasion (Christmas morning, Valentine’s Day, anniversary, birthday, etc.), you would open the envelope together or with the family or friends of your choice, and celebrate.  You control when, where and how you learn the momentous news. This gives you the ability to make an occasion out of learning the sex of your baby, but still gives you time to paint the baby’s room pink or blue before the baby’s arrival.

It seems like such a simple, obvious idea, yet I had never heard it before.  Hopefully, it is something worth passing on to anyone who is pregnant and is wondering if they should ask to know the sex at the ultrasound visit.

But, just remember that sometimes the sex is not clearly identifiable from an ultrasound due to the baby’s positioning or the ultrasound technician’s skill.  To be absolutely certain of the sex, you would need a diagnostic test, such as a CVS or amniocentesis.  With these tests you might be able to let your doctor know in advance not to reveal the sex to you at the time he/she receives the test results.

But, then again, if you are particularly stressed about knowing the baby’s sex, or you simply want to hear the words “it’s a girl!”  or “it’s a boy! “ after your hours of labor and delivery, there is always purple or yellow paint.

Blood test vs. amniocentesis

Thursday, January 13th, 2011

blood-testsResearchers are working on a new blood test that has the potential to diagnose Down syndrome in women who are at high risk for having a baby with this condition. If proven successful, this test might eliminate the need for the more invasive and risk-related tests of amniocentesis and chorionic villus sampling (CVS).  Both amniocentesis and CVS carry a risk of miscarriage.

A study conducted at the Chinese University of Hong Kong and recently published in the British Medical Journal (BMJ), included 753 pregnant women. Of these, 86 women were carrying a fetus with Down syndrome. There were no false-negative results with the new test. All babies with Down syndrome were detected. The study authors state that “If referrals for amniocentesis or chorionic villus sampling were based on the sequencing test results, about 98% of the invasive diagnostic procedures could be avoided. “

Further evaluation of this technology needs to be conducted before it is offered to the public, but this is exciting and hopeful science.  While the test won’t be available for at least another year, and the cost may be high, and currently it tests only for Down syndrome and not other conditions, it holds promise for the future.  It will be a new and safe screening tool to help us gather information about our developing babies.