Posts Tagged ‘ultrasound’

Ultrasound options

Monday, February 28th, 2011

Over the next couple of days, I’m going to write about ultrasound.  There are different types that are used for different purposes and I’ll review them.

Ultrasonography is the most commonly used tool for viewing a developing fetus. Ultrasound has been safely utilized for over 40 years, but only specially trained technicians and providers should perform an ultrasound, and only for medically necessary reasons.

Using sound waves to bounce off curves and shapes within your body, technicians are able to translate light and dark patterns into images of internal organs or a developing fetus. Standard ultrasound creates a 2-D image of a developing baby in mom’s womb. A woman may have a standard ultrasound during the first trimester to confirm and date the pregnancy (or to find out if she’s having twins like her mother did!)  But not all providers offer it that early in pregnancy, so don’t be upset if yours doesn’t. It also can be used to check the positioning of the placenta or level of amniotic fluid later on.

Most providers request an ultrasound between 18 and 20 weeks. The procedure lasts about 20 minutes and can be performed abdominally (by moving a transducer over the belly) or vaginally (using a slender wand-like device that is placed inside the vagina). A full bladder acts like a mirror and helps the technician get a clearer view, hence the recommendation of drinking a few glasses of water before the procedure.  This is great for the tech, but might get slightly squirmy for mom after a while.

Tomorrow’s post – What’s Doppler imaging (nope, not part of the weather report) and fetal echocardiography?

Choroid plexus cysts

Friday, December 3rd, 2010

Sometimes technology can be a double-edged sword.  For instance, we all love seeing those first ultrasound pictures of our babies—it is so exciting and amazing!  But ultrasound can also show us things that may or may not have consequences.  Choroid plexus cysts are an example.

The choroid plexus is the area of the brain that produces the fluid that surrounds the brain and spinal cord. This is not an area of the brain that involves learning or thinking. Occasionally, one or more cysts can form in the choroid plexus. These cysts are made of blood vessels and tissue. They aren’t a problem by themselves and they do not cause mental retardation or learning problems.

Using ultrasound, a health care provider can see these cysts in about 1 in 120 pregnancies at 15 to 20 weeks gestation. Most disappear during pregnancy or within several months after birth and are no risk to the baby.

However, if choroid plexus cysts are present and maternal blood testing (such as the quad screen) and/or the ultrasound itself shows other signs of risk, together it may all indicate a possible genetic defect. In this case, testing with higher-level ultrasound and amniocentesis may be offered to confirm or rule out serious problems.

Hearing your baby has choroid plexus cysts can be scary but don’t panic!  Just remember that most of the time this is a benign finding and does not mean that there is a problem.

Do those blood tests confuse you?

Monday, August 9th, 2010

For those of you who are pregnant, sometime between 15-20 weeks of pregnancy, you will be offered maternal serum screening.  What is this?  And more importantly, what do the results mean?  I think maternal blood screening is one of the most misunderstood tests in pregnancy.  And for some women it can be a very nerve-wracking experience.

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women regardless of age be offered a screening test for Down syndrome and certain other birth defects.  This is a blood test that looks at the levels of either 3 or 4 (depending on the test) chemicals that are present in a pregnant woman’s blood.  The chemicals are AFP (alpha fetoprotein), hCG (human chorionic gonadotropin—the same chemical that a home pregnancy test measures), estriol, and recently most labs have added a fourth substance, inhibin A.  These chemicals are present in every pregnant woman’s blood.  Some of them are produced by the fetus while others are hormones produced by the placenta.

Maternal serum tests such as the triple screen or the quad screen as they are commonly called, look at the levels of these 3 or 4 chemicals in the mother’s blood and the woman’s age, weight, race, number of fetuses (e.g. twins) and whether she has diabetes that requires insulin treatment.  Then given all of those factors and the levels of the 3 or 4 chemicals the laboratory can determine the chance that a woman has a baby with Down syndrome, a neural tube defect (spina bifida), trisomy 18, or abdominal wall defects.

There are two different ways that the results may be reported.  A woman may receive her test result as a ratio. For example, her baby has a 1 in 500 chance for Down syndrome. Or, in some cases, a woman’s test results are reported as normal (screen negative) or abnormal (screen positive), depending on whether her results fall below or above a cut-off point (usually about 1 in 270).

The test is NOT a diagnosis of any of these conditions though.  This is where there is a lot of confusion.  By definition, screening tests do not diagnose a condition.  They only determine whether there is an increased risk for the condition.  The good news is that of all of the women who screen positive, only a small percentage will actually have a baby with one of these disorders.  Many times women have an abnormal result simply because their fetus is a few weeks older or younger than previously thought.

For women with abnormal results, the next step is usually an ultrasound. This test can check the gestational age of the fetus and show if a woman is carrying multiples. If either of these factors accounts for the abnormal test result, no further testing is needed. If ultrasound does not explain the abnormal test result, amniocentesis will be offered.  An amniocentesis is an invasive test where the doctor uses a needle to remove some of the amniotic fluid around the baby.  Although amnio does pose a very slight risk of miscarriage (1/4 of one percent or 1/500), it is extremely accurate and usually can give a pregnant woman a definitive answer.  Should a problem exist, arrangements can be made in advance for special care of the newborn at delivery.

Does a retroverted (tipped) uterus pose pregnancy risks?

Tuesday, August 3rd, 2010

Almost never. About 20 percent of women have a uterus that tips slightly backward. This is considered a normal variant of uterine positioning in most women.  It’s possible that some women may develop a retroverted uterus due to fibroids or scar tissue in the pelvis. Generally, the uterus straightens by early in the second trimester and does not contribute to pregnancy complications.

At about 12 weeks of pregnancy, the top of the uterus normally extends past the pelvic cavity. Rarely, a retroverted uterus may become trapped in the pelvis. This is called uterine incarceration and can cause pain and difficulty passing urine. An ultrasound can diagnose retroverted uterus in women with these symptoms. Simple treatments, including bladder drainage, positioning exercises the woman can do at home, or gentle manipulation by the health care provider, usually can restore the uterus to its normal position. Occasionally, an untreated incarcerated uterus may contribute to second-trimester miscarriage.

The placenta and fetal circulation

Thursday, January 14th, 2010

insideThe placenta is a remarkable organ that connects the mother’s blood supply with that of the developing fetus through the umbilical cord.  It transports oxygen and nutrients to the baby’s blood and returns the baby’s waste to the mom’s blood for disposal through her kidneys.

The placenta, formed from the same cells as the embryo, attaches to the wall of the uterus and to the umbilical cord. Oxygen-rich, nutritious blood travels from Mom to the fetus by the umbilical vein in the umbilical cord.  The umbilical vein delivers the blood to the liver and then much of it travels on to the right side of the heart. Here it mixes with blood of the fetus and is sent on through two special openings, bypassing the nonfunctioning lungs, into the left side of the heart for distribution to the entire body.  After completing the circuit, the blood that has delivered oxygen and nutrients to the fetus now flows via major vessels back to the umbilical cord where the two umbilical cord arteries carry it back to the placenta.

While the placenta allows oxygen and nutrients to pass through it, it also filters out many potentially harmful substances and infections. Near term, the placenta produces hormones that play a role in triggering labor and delivery.  After the baby is born, the placenta’s job is done and the placenta is delivered as the afterbirth.

In some cases the placenta may not develop correctly or function as well as it should. It may be too thin, too thick or have an extra lobe, or the membranes may be improperly attached.  Most of these issues are detected via ultrasound.  Signs of a problem include vaginal bleeding and/or continuous abdominal pain.  If you’re pregnant and have questions about your placenta, ask your doctor about it during an ultrasound.

Fifth disease and pregnancy

Thursday, June 4th, 2009

sick-child-21Fifth disease is a childhood illness that about half of us come down with when we’re kids, making us immune to it as adults.  It’s caused by parvovirus B19.  It got its odd name many years ago when it appeared fifth in a list of what were considered the common causes of childhood rash and fever.  Most often, it’s not a big deal in childhood, but it might be to a developing fetus if the mother contracts it during pregnancy.

Fifth disease  is a common, usually mild illness spread through the air from an infected person’s cough or sneeze. In children, it causes a distinctive “slapped cheek” rash and, less commonly, a low-grade fever, headache, sore throat and joint pain. Infected adults are less likely to develop a rash, but often experience joint pain and swelling, sometimes with mild flu-like symptoms. Symptoms generally appear between 4 and 14 days after exposure. 

Fetal infection is rare. However, when a fetus does become infected, the virus can disrupt its ability to produce red blood cells, sometimes leading to a dangerous form of anemia and heart problems.  Serious consequences are more likely when a pregnant woman contracts the infection in the first 20 weeks of pregnancy.

To reduce the risk of infection, pregnant women should wash their hands thoroughly after touching tissues used by infected children and dispose of these tissues promptly. They also should avoid sharing drinking glasses or utensils with anyone who has or was exposed to the illness.

A pregnant woman who has been exposed to fifth disease should consult her provider promptly.  Blood tests can determine susceptibility or help diagnose the illness. If she is infected, her provider monitors the pregnancy carefully for signs of fetal problems.  There is no drug to treat the disease. The provider will most likely recommend repeated ultrasound examinations (weekly or every other week) for 8-12 weeks after the mother was infected. If ultrasound does not show any problems during this time, no further treatment is needed.

You can read questions and answers about this in the fact sheet written by the Organization of Teratology Information Specialists (OTIS).

Partnering with the future dad

Tuesday, February 24th, 2009

pregnant-coupleBecoming a dad can be exciting and confusing.  Both of you will be going through new territory when you’re pregnant.  Ask your partner to go with you to your prenatal care visits when the time comes.  It will help him learn a lot and will help the two of you, and your health care provider, become a strong team.

If he seems a bit shy about this, let him know that during the prenatal visit at the end of the first trimester, he will be able to hear the baby’s heartbeat.  Way cool!  During the second trimester, you probably will have an ultrasound test to take a look at the baby.  You’ll both be able to see your baby’s head, arms, hands, legs and feet.  Hello in there!  You might even find out the sex of the baby if you want to. In the third trimester, he will be able to help formulate a plan with you and your health care provider about the best way he can help during labor and delivery.

Talk about it now.  Get him involved from the get go.

My level II sono

Tuesday, October 21st, 2008

 A couple of Fridays ago I had a level II sonogram. I had just completed my 20th week at the time. A level II is a more detailed exam which may use more sophisticated ultrasound equipment. I have an amazing new picture of my little one. My husband thinks I’m crazy, but I think the baby has my nose. And no…we did not find out the sex. I want to be surprised. 

After about an hour in the waiting room we were called back by the technician. It was a very busy day in the doctor’s office. We followed her into an exam room where she motioned for me to hop up on the exam table. I was so surprised when she explained that a level II sonogram would take about 45-60 minutes. I had no idea it would take that long otherwise I would have eaten lunch beforehand! 

I made myself comfortable on the exam table while the tech applied a blue gel all over my belly.  Then she picked up the transducer and turned the screen toward us. Hello baby! She did a full body scan measuring all of the long bones, identifying major organs, including the heart and brain, nose and mouth. The tech said that even if we wanted to know the sex it wouldn’t be easy because the little legs were too close together and crossed at the ankle.

At the end of the exam I asked the tech if everything looked OK and she said that she did not interpret results. The doctor was responsible for that and the results would be faxed to my midwife’s office in a couple of days. She printed out a ton of pictures and gave us a few to keep. Fortunately, in my situation there was no medical reason for the level II so I wasn’t overly concerned about the results. It was still nice to hear that the baby is measuring and developing well though.

Screening for birth defects

Tuesday, September 9th, 2008

At my last prenatal appointment I had a combination of tests done to screen for birth   defects such as Down syndrome and Trisomy 13 and 18. I was nervous going, but my husband was with me for support. My visit started with an ultrasound. The doctor rubbed a hand-held device (called a transducer) across my belly. The baby was face up and the doctor needed him/her to turn to the side in order to measure the thickness at the back of the neck (called nuchal translucency).  We waited and waited, but he/she wouldn’t budge. I certainly didn’t mind because I was able to admire the beautiful image on the screen longer.

After several minutes, the doctor finally called for a nurse. She brought me a very sweet orange drink and the doctor said he would be back in less than 10 minutes. I was thinking, “yeah right, this isn’t going to work.” Well, wouldn’t you know it. When he came back and put the transducer on my belly, there it was — the most perfect profile. I guess the baby just needed a little energy. Using the mouse on the ultrasound machine, he was able to measure the back of the neck.

Then I was passed off to the nurse who took a blood sample. I don’t know if this is always the case with maternal blood screening, but she pricked my finger and placed about 5 or 6 drops of blood on a card. The office sent the blood sample to a lab and I would get the results back in about four days. The lab calculated my risk of chromosomal birth defects, using the combined results of my blood test and ultrasound exam.

I received a call a few days later. I was told that based on my age, blood work and ultrasound my risk for Down syndrome was 1 in 1, 610 and my risk for Trisomy 18/13 was 1 in > 10,000. I know that no test can gaurantee the birth of a healthy baby, but I was so relieved. It’s always nice to here reassuring news. Waiting for test results can be so stressful.

It’s a boy! It’s a girl!

Thursday, July 17th, 2008

Are you planning to find out ahead of time or do you want to be surprised? During your second trimester of pregnancy you can learn the sex of your baby via ultrasound. Just keep in mind that ultrasound results are not 100% accurate — unlike amniocentesis, which determines the sex of the baby through DNA analysis. It really depends on your stage of pregnancy, position of the fetus, skill level of the technician and the equipment being used. 

My two sisters each have three children. They both agree that finding out the sex of the baby at the very moment of birth is one of the greatest feelings in the world. My sister-in-law has two children and says finding out the sex beforehand helped her to bond with her babies sooner and with planning ahead. There’s no right or wrong decision! It’s a personal one between you and your partner, so have fun with it no matter what you choose.

Reasons to find out the baby’s sex may include: you only have to pick one name, you can buy specific clothing, decorate the nursery, bond with a specific baby, and the technology exists so why not?

Reasons to wait may include: the excitement of not knowing, not knowing may help with coping during the last few weeks of pregnancy, knowing the sex is not important – you’ll love your baby either way, it’s the natural way to go

What do you plan to do?