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Genetic Screening Options

Prenatal and Preconception Screening, Testing, and Counseling

Whether before or after conception, we offer options for screening and testing that can help in preparing for a healthy baby. Your decisions about screening and testing options are very personal ones. This document gives some basics, however your provider will also refer you for a genetic consultation. The genetic counselor will review your personal and family history and provide you with more detailed information about your screening and testing choices.

Genetic Carrier Screening involves a blood sample and can be performed prior to or during a pregnancy. It can identify those at increased risk of having a child with certain genetic conditions. Screening most often includes common disorders such as Cystic Fibrosis, Spinal Muscular Atrophy and Sickle Cell Anemia. Doing the screening before or early in pregnancy can increase your options. Expanded carrier screening panels are also available. Please speak with your provider for more information or review our Genetic Carrier Screening fact sheet.

Genetic Counseling is a routine part of the prenatal screening process for all pregnant people. It is an in person or telehealth visit, in which the genetic counselor will discuss your screening and testing options and work with you to arrange the tests you choose. This will include a discussion of risks and options for those who will be over 35 years at the time of delivery. They will also communicate results to you when completed. If results raise concerns, they will explain them and help you pursue additional screening or testing, if desired, or arrange consultations and referrals when appropriate.

Genetic counseling appointments can also be scheduled for a variety of other reasons. This includes pregnancies in which ultrasound findings have raised concern, or families who have a child or other close relative with a birth defect, physical or cognitive disabilities, or genetic disorder. Genetic counseling is also available for carriers for a genetic condition, such as Tay-Sachs, Sickle Cell Anemia, Spinal Muscular Atrophy or Cystic Fibrosis. Pregnant people who have been exposed to agents, such as medications, that may be harmful to the baby may seek genetic counseling.

Prenatal Screening includes options that can identify whether your baby is more or less likely to have certain conditions. A genetic counseling visit is typically scheduled in combination with these screens. Prenatal screening is non-invasive, uses a blood sample and ultrasound, and can start in the early stages of your pregnancy through the second trimester. Screening can't make a definitive diagnosis but will find most pregnancies with a higher risk. They carry no risk to the baby and are most often reassuring. If results indicate an increased risk for a condition, your genetic counselor or health care provider will discuss them with you, offer further testing and make a plan for further care.

Screening Options

FIRST TRIMESTER

  • First Trimester Screen
    • A blood sample is obtained by a finger stick combined with ultrasound to estimate the risk of Down syndrome, trisomy 13 and trisomy 18
    • This screening is done between 11 weeks and 13 weeks, 6 days
    • Results are typically available in about 5 days
  • Cell free DNA Screening: cfDNA or Noninvasive Prenatal Testing (NIPT)
    • A blood draw used to assess the risk of Down syndrome, trisomy 18, trisomy 13, and sex chromosome abnormalities
    • This is more commonly used for those at increased risk for having a baby with birth defects. These risks include advanced maternal age, history of chromosomal abnormalities, or previous abnormal screening results
    • It can be considered by a patient with a low risk pregnancy, however may not be covered by insurance
    • The test can be done after 10 weeks of pregnancy
    • Results are usually available in about 7 days

SECOND TRIMESTER

  • Maternal Serum Alpha-Fetoprotein (MSAFP)
    • MSAFP is a blood draw to screen for open neural tube defects such as spina bifida and other more rare conditions
    • Typically the MSFAP is done between weeks 15 and 24 of pregnancy
  • Tetra Screen (Includes MSAFP Screen)
    • Uses a blood sample to estimate the risk of Down syndrome and trisomy 18
    • This would routinely be offered to those who have not had a first trimester screen
    • Typically this screening is done between weeks 15 and 20 of pregnancy
    • Results are usually available in about 7 days
  • Ultrasound or Sonogram
    • Uses sound waves to create computer images that can evaluate the growth and development of the baby
    • An anatomy ultrasound is routinely performed at approximately 20 weeks of pregnancy
    • Any differences or abnormalities that are found are discussed with a Maternal Fetal Medicine physician after the ultrasound. Our physician will explain the finding and discuss options for further screening, prenatal diagnosis, or special care. They may offer a visit with the genetic counselor for additional information and support.

Prenatal Diagnostic Options

Diagnostic testing is most often offered to patients who will be over 35 years at delivery, who have a positive screening results, or who have a child or other family member with a birth defect or genetic condition. Genetic counseling is provided to review these tests if they are being considered. These tests provide definitive answers about chromosome abnormalities and certain genetic disorders. Both tests obtain cells from the pregnancy without touching the baby, but each carry a small risk for complications. They are usually considered to be uncomfortable, not painful, and are short procedures. Other specialized tests can be added and will be discussed as an option with either procedure.

CHORIONIC VILLUS SAMPLING (CVS)

  • In CVS testing, a small sample of cells is taken from the placenta, either with a vaginal or abdominal approach, under ultrasound guidance
  • The CVS is typically performed between 11 and 14 weeks of pregnancy
  • The risk for a complication that may lead to miscarriage is less than 1 in 500 (less than 0.2 of 1%)
  • Final results are typically available in about 10-14 days
  • Follow-up screening for neural tube defects will be offered with MSAFP (see page 9)

AMNIOCENTESIS

  • In amniocentesis, under ultrasound-guidance, a thin needle is used to withdraw a small amount of amniotic fluid or ‘birth’ fluid around the baby
  • The amniocentesis will not only diagnose chromosomal abnormalities, but can also diagnose neural tube defects
  • The procedure is typically performed between 15 and 20 weeks of pregnancy
  • The risk for complications that may lead to miscarriage is less than 1 in 1,000 (less than 0.1 of 1%)
  • Final results are typically available in about 10-14 days

WILL MY HEALTH INSURANCE COVER TESTING?

Most insurance plans will cover prenatal screening with first trimester screening or tetra screening. The cell free DNA screening and prenatal diagnosis are usually covered for patients at increased risk including those over 35 years old, pregnancies with abnormal screening or ultrasound, or known risk for a genetic disorder. It may be covered for low risk patients, however you would be advised to check with your insurance regarding coverage. You can be provided with codes to use in discussing this with insurance. Additionally, you may have deductibles and copays that will apply.

ADDITIONAL QUESTIONS TO CONSIDER:

All of the referenced screening and testing is optional and there are some things you can think about as you make decisions on proceeding:

  • Whether the results will impact your choices in pregnancy
  • The accuracy of the screening or testing
  • Any risks that may be associated with the testing

Please remember that your health care provider and genetic counselor are trained to focus on your particular situation and help you make the best decision for you.

WHERE CAN I LEARN MORE?

Cancer Genetic Counseling:
Individuals with a family history of cancer or related questions are encouraged to contact the Ruth Paul Cancer Genetics and Prevention Center at 202.677.6903 or gwdocs.com/cancer-genetic-counseling.

You will learn more and have the opportunity to ask individual questions at your genetic counseling visit. However, these websites may be helpful:

Conveniently Located

Clinical Trials

  • This study is looking at the relationship between sleep and perinatal mood disorders such as depression and anxiety. Participants will wear a wrist monitor like a fit bit for 10 days to help researchers gain information into sleep patterns during pregnancy and postpartum and will answer questionnaires about their mood.
  • Preterm birth is one of the leading causes of neonatal morbidity and mortality. One of the most significant risk factors is a history of a prior spontaneous preterm birth. Intramuscular progesterone is the only FDA approved medication for the prevention of recurrent preterm birth. Vaginal progesterone is not FDA approved for the prevention of recurrent preterm birth, but has been found to beneficial. Given the presence of trials demonstrating efficacy for both intramuscular and vaginal progesterone in the prevention of recurrent preterm birth, but limited information one being more superior to the other, we are performing a trial comparing vaginal progesterone and intramuscular progesterone for the prevention of recurrent spontaneous preterm birth in women with a history of prior spontaneous preterm birth.
  • [This study is no longer recruiting.] The SONATA Study is an FDA-approved clinical study designed to establish the safety and effectiveness of a new, investigational device to reduce heavy menstrual bleeding caused by uterine fibroids. The device, called the SONATA System, targets fibroids rather than treatment or removing the entire uterus. If effective, this device will provide an alternative to hysterectomy that is: incision-free, preserves the uterus, does not require general anesthesia and is an outpatient procedure.
  • Women with twin pregnancy who have a dilated (open) cervix detected on physical exam before 24 weeks are at increased risk for delivering their babies preterm (before 37 weeks gestation). Prematurity is associated with many complications for the babies including respiratory (breathing) problems, bleeding inside of the brain (a form of stroke), increased risk of infection, kidney, temperature and feeding problems. The primary objective of this study is to determine if physical exam indicated cerclage use reduces the incidence of spontaneous PTB in asymptomatic women with twin gestations with cervical dilation diagnosed on pelvic exam before 24 weeks of gestation.
  • Tranexamic acid was shown to significantly reduce risk of mortality when given to women with diagnosed postpartum hemorrhage in the recent Lancet WOMAN Trial.* The purpose of this study is to determine the optimal dose for using tranexamic acid to prevent postpartum hemorrhage during routine cesarean section. Women undergoing cesarean section will be eligible and must not have a history of blood clots or a known clotting condition. *http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)31111-X/fulltext
  • In this study, we are developing non-invasive tools to identify early signs of abnormalities of the placental function using arterial spin labeling (ASL) based on fetal MRI. ASL is a particularly attractive method for early and safe monitoring during pregnancy given that ASL is completely non-invasive and does not require contrast agents or exposure to ionizing radiation. Our specific aim is to develop and validate placental perfusion imaging with substantially improved image quality and sensitivity to abnormalities.
  • This study is being performed at Children's National Health System. We are trying to understand how the normal fetus controls blood flow to the different parts of the body such as the lungs and brain. We will measure your baby's blood flow using the same ultrasound approach used by your obstetrician. We will test your baby's control of blood flow by measuring the responses to changes in your (the mom's), levels of oxygen and carbon dioxide. We will make these changes by asking you to breathe extra oxygen for short periods of time. If your obstetrician determines that your pregnancy is uncomplicated, you and your baby are eligible for this study.