Fetal testing and treatment

Prenatal screening services in North Texas

Fetal testing is a choice a woman and her partner must make. North Texas Perinatal Associates provides support and guidance for patients and their families.

Your doctor may have referred you to our practice because of our experience in maternal conditions that can complicate pregnancy, including:

  • Autoimmune disorders
  • Cervical incompetence
  • Diabetes
  • High blood pressure
  • Prior pregnancy complications

When and why should I have fetal testing and treatment?

If a prenatal screening that shows the baby may have a birth defect, additional fetal tests may be performed. While screening only reveals the possibility of having a child with a birth defect, follow-up fetal testing can confirm a diagnosis.

If you are 35 or older or have already given birth to a child with a birth defect or have a family history of birth defects, your gynecologist will recommend fetal testing. It’s also an option for women who have prenatal screening results that indicate you could have a child with a birth defect.

If a fetal test has shown your child will have a birth defect and you decide to have your baby, your gynecologist can make plans for you to give birth at a hospital that is prepared to care for your newborn's special needs. The doctor may also refer you to a pediatric or surgical specialist to discuss more details about your baby’s health and preparations for his or her arrival.

These questions may be helpful to you:

  • Do you live in a rural or isolated area? If so, you may want to consider fetal testing. If an abnormality is found, you can give birth at a hospital that can offer the care you need.
  • If your ultrasound screen has shown a possible birth defect, do you want to know if there may be other abnormalities associated with it? If you need more information to continue the pregnancy, fetal testing could provide those answers.
  • Are you unsure what to do? Although it can be hard to think about, it can be helpful to compare worst-case scenarios. Which would be harder for you: to raise a baby with a birth defect or to lose a normal pregnancy.

Amniocentesis

Amniocentesis, usually done between 16 and 18 weeks of pregnancy, is a procedure in which a doctor draws fluid from the amniotic sac to test for genetic birth defects and other conditions. Since the cells in the fluid have the same genetic makeup as the fetus, they can be tested for abnormalities.

One woman out of every 200 who has an amniocentesis will have an issue or develop an infection and lose the pregnancy. Therefore, it can be one of the most difficult decisions women make during pregnancy.

During the procedure

Ultrasound is used to help the gynecologist determine where the baby and placenta are located. Next, a needle is inserted through the abdomen and into the uterus to extract amniotic fluid. Although it may be stressful and you may feel some pressure, you will not feel pain during the procedure.

After the procedure

Results of the amniocentesis generally arrive within two to three weeks. If an abnormality is identified, this information can be used to help you decide to continue or terminate your pregnancy.

Chorionic villus sampling

Chorionic villus sampling (CVS) is a test in which cells are taken from tiny fingerlike projections, called chorionic villi, on your placenta during weeks 10 to 13 of pregnancy. It is highly accurate and can detect chromosomal abnormalities 98 percent of the time. CVS is usually done in a hospital but also can be performed in a gynecologist’s office.

During the procedure

Depending on where your placenta is located, your gynecologist will perform a transcervical or transabdominal CVS. Most women experience some type of discomfort, such as mild or moderate cramps.

  • Transcervical procedure: Your gynecologist will insert a long, thin tube into your vagina then into your uterus, using ultrasound imaging to guide the tube. Next, the tube is placed between the uterine lining and the chorion, which is the fetal membrane that will eventually form the fetal side of the placenta. A sample of the chorionic villi will then be removed for study.
  • Transabdominal procedure: Ultrasound will be used to locate the placenta and to view the uterine walls. Then, a needle will be inserted through the abdomen and uterine wall to the edge of the placenta, where cells will be drawn up through the needle.

After the procedure

The gynecologist will send the samples to a lab for genetic analysis. Test results are usually available in one or two weeks.

Fetal assessment

Additional testing is often used during the third trimester of a high-risk pregnancy to evaluate your baby’s health. Fetal well-being can be assessed in several ways, including:

  • Maternal perception of fetal movement, or “kick counts”
  • Studying the baby’s heart rate tracing
  • Using ultrasound to observe the baby’s movements and amniotic fluid levels
  • Viewing blood flow in the umbilical cord blood and/or the baby’s brain with ultrasound Doppler studies

The clinical situation will determine when testing should begin and how often it should occur.

Genetic screening

Through genetic screening, parents can discover the likelihood of having a child with a genetic birth defect, such as Down syndrome. Ultrasound is also used during pregnancy to screen for birth defects; however, neither procedure provides a formal diagnosis. If genetic screening or ultrasound indicates a baby could have a birth defect, parents may choose to have a prenatal diagnostic test performed to determine whether the baby in fact has a birth defect.

In addition to understanding genetic screening, ultrasound and prenatal diagnosis testing options, it may be helpful to learn more about the different types of birth defects, how they can be treated or managed and how they may impact children and their families.

Your gynecologist will likely offer first trimester screening for Down syndrome. This screening is recommended by the American College of Obstetricians and Gynecologists for all pregnant women. Beyond the first trimester, genetic testing is usually only offered to families who are considered high-risk for a particular genetic condition.

Additional screenings include:

  • Carrier screening: Even before you become pregnant, you and your partner can be screened to find out whether either of you carries a gene for certain inherited disorders. During the test, a blood sample or tissue sample will be swabbed from inside your cheek and tested. Carrier screening can be done before or during pregnancy.
  • First trimester screening: This non-invasive evaluation, done between weeks 11 and 13, includes a blood test and ultrasound of the fetus. The purpose of first trimester screening is to check for genetic birth defects related to your baby’s heart or other genetic disorders.
  • Second trimester screening: Also known as Triple or Quad screens, these are performed between 15 and 20 weeks. They include blood tests that measure two pregnancy-related hormones and an ultrasound to check for genetic birth defects. Second trimester screenings are considered less accurate than first trimester screens.
  • Third trimester screening: These are routine checks conducted at every prenatal visit, such as a urine test, blood pressure check, measurement of the uterus and fetal heartbeat. You will also be tested to determine whether you have a type of bacteria that can be passed to your baby during birth. If you test positive, you will take antibiotics during labor to prevent transmission to your baby.

Ultrasound screening

Ultrasound can be used along with genetic screening to assess a developing baby’s risk of Down syndrome and other birth defects, including heart problems.

When ultrasound is used in this way, it is called a nuchal translucency scan, or NT scan. It is performed when you are between 11 and 14 weeks pregnant because at this stage of development, your baby’s neck is still transparent. Therefore, the scan can measure the clear space in the tissue behind your baby’s neck. If the scan is abnormal, there will likely be more fluid accumulated at the back of the neck during the first trimester.

About the procedure

During an NT scan, a small, handheld device that emits sound waves is rubbed across your abdomen by the clinician. These waves bounce off the fetus and create an on-screen image of the fetus and your uterus.

After the procedure

Your gynecologist will discuss the screening results. It is important to know that babies with a normal ultrasound screen may end up having birth defects or genetic disorders that cannot be detected.

Prenatal diagnostic testing

If you have a positive result during any of these screenings, it does not confirm that your baby has an abnormality, but it does mean that you should discuss prenatal diagnostic testing with your gynecologist.

Percutaneous umbilical blood sampling and intrauterine transfusion

Percutaneous umbilical blood sampling (PUBS) and intrauterine transfusion (IUT) are used to sample the baby’s blood to evaluate and to treat specific fetal problems. PUBS involves using ultrasound to direct a needle through the mother’s abdomen and uterus and into the vein in the baby’s umbilical cord to obtain a sample of the baby’s blood. IUT is done when the PUBS shows that the baby has anemia (low blood count) and it involves transfusing blood through the needle in the baby’s umbilical cord to treat the anemia while the baby is still in the uterus.

Fortunately, the need for either of these procedures is rare now as medical breakthroughs such as Rhogam for preventing RH disease and middle cerebral artery Doppler to assess for fetal anemia have been introduced. Because these procedures are required less often, it is important to find providers who have experience in these procedures. Our physicians have years of experience with PUBS/IUT and work diligently to maintain their skill level to make the procedure as safe as possible for the mothers and babies who require it.

Preconception counseling and treatment

Counseling for pregnancy risks and complications in North Texas

North Texas Perinatal Associates helps couples who are starting the pregnancy journey with treatments and procedures.

Some families will benefit from counseling about pregnancy risks and management options prior to trying to conceive. Our maternal-fetal medicine specialists combine expertise and empathy to equip couples with valuable knowledge prior to conceiving.

Our experienced physicians listen to each patient and address their specific needs based on a variety of considerations including:

  • A previously complicated pregnancy due to preterm labor, preterm delivery and/or other conditions
  • Genetic disorders
  • Fetal anomalies
  • Maternal medical conditions, such as diabetes or high blood pressure
  • Recurrent pregnancy loss

Preconception counseling can help clarify specific pregnancy risks and evaluate possible means to minimize risks to both mother and baby. Counseling may also involve meeting with one of our genetic counselors to discuss ways to screen parents-to-be for genetic diseases as well as provide screening options during pregnancy to evaluate chromosomal abnormalities.

Beyond their individual training and collective years of experience, our physicians provide an extensive array of diagnostic tests and services tailored to meet the specific needs of your pregnancy.

In addition to a well-balanced diet, essential lifestyle habits should include:

  • Taking a prenatal (daily) vitamin with folic acid prior to conception
  • Being physically active
  • Elimination of tobacco, alcohol and illicit drugs
  • Avoiding environmental exposures like second-hand smoke, lead, radiation and litter boxes

Transabdominal cerclage

A small number of women with cervical incompetence treated with a vaginal cerclage may still suffer preterm delivery. There are also a small number of women who have too little cervical length to allow for vaginal cerclage placement. In this subset of women, a transabdominal cerclage (TAC) may provide the support they need to successfully carry a pregnancy.

TAC placement requires entering the maternal abdomen through an incision (like a cesarean section incision) or through laparoscopy. The TAC allows a suture for structural support to be placed much higher on the cervix/lower uterus to provide the needed support to carry a pregnancy. Once placed, the TAC remains in place. Patients require a Cesarean section for delivery.

Transvaginal cerclage

Women who have had prior pregnancy losses with painless premature opening of the cervix and delivery during their second trimester may be diagnosed with cervical insufficiency or cervical incompetence.

Women who have had prior cervical surgery for dysplasia and women with a history of other cervical trauma, such as multiple D&Cs or cervical laceration during a prior pregnancy, may be at increased risk for cervical incompetence. Therapy can include supplementation with progesterone and vaginal cerclage. Vaginal cerclage involves placing a suture around the upper cervix in a purse-string fashion to provide additional cervical support and to decrease the risk of preterm birth. A vaginal cerclage is generally a day surgery procedure. The cerclage can be removed in the office around 36 or 37 weeks of pregnancy, and vaginal delivery can occur after cerclage removal.

While most cervical cerclage procedures are performed at the end of the first trimester or early in the second trimester as a prophylactic cerclage in women with prior preterm delivery, some women may be referred for an emergent or rescue cervical cerclage. A patient may be considered for an exam-indicated cerclage if they are found to have a dilated cervix with protrusion of the bag of water into the cervix or if they have a history of prior preterm birth and are found to have a cervix that has shortened during the second trimester.