What Is Ultrasound?
Ultrasound is a non-invasive imaging method that uses high-frequency sound waves to produce images of structures within the body. The high-frequency sound waves are concentrated into a thin beam and directed into the body with a small hand-held device called a transducer. The sound waves reflect off internal structures. The returning echoes are received by the transducer and then processed by a computer to produce real-time images. Ultrasound is commonly used to evaluate the abdominal and pelvic organs, breasts, thyroid gland, testes, as well as blood flow in arteries and veins.
One of the most common uses for an ultrasound is during pregnancy. The procedure is similar and instead of looking at internal organs, we’ll be looking specifically at the uterus. There are generally two instances to get an ultrasound during pregnancy, in the first and third trimester, however pending complications and doctor’s instructions a vaginal ultrasound can be performed as early as 6 weeks into pregnancy.
During the first trimester scan we’re looking for the fetus’s heartbeat, checking for twins and measuring the fetus’s development to anticipate a delivery date. During the third trimester ultrasound more organs are starting to become visible and we’re looking at the baby’s sex and checking for healthy growth.
There are 2 common types of ultrasounds used during pregnancy:
Transvaginal Ultrasound – This is an internal exam. An ultrasound probe is placed inside the vagina, this allows it to create clearer images of the pelvic area. This scan can be performed early on in the pregnancy and is used to identify pregnancy complications. It can last between 30 – 60 minutes. This is a very low risk exam, but you may feel some minor discomfort during the procedure.
Abdominal Ultrasound – Conductive ultrasound gel will be spread on your lower abdomen to help decrease static in the sonogram image. An ultrasound probe will be used to see through the gel into your uterus and and live image will be shown on the screen. An abdominal ultrasound can take around 30 minutes.
PREGNANCY ULTRASOUND FAQS:
Q: How many ultrasounds during pregnancy are recommended?
A: Generally there are two ultrasounds during pregnancy, however a doctor may recommend more for a higher risk pregnancy. It is not suggested to get ultrasounds recreationally, since long term effects of frequent ultrasounds have not been studied.
Q: When is the first ultrasound / sonography during pregnancy?
A: A transvaginal ultrasound can be performed early on before the 6 week mark, it’s generally used for special circumstances recommended by your doctor. However, a regular abdominal ultrasound is performed around the 8 – 12 week mark.
What Should I Expect During an Ultrasound Procedure?
During the ultrasound, you will be positioned on an exam table and a clear gel will be applied to your skin. The gel is used to eliminate air bubbles between the transducer and your body, since sound waves travel very poorly through air. The transducer is pressed against the skin and moved back and forth to visualize the area of interest. It is usually painless, although you may experience some discomfort from the pressure applied by the transducer. The examination usually takes 15 to 45 minutes depending on the exam. You may return to your normal activities after the exam.
Preparing for an Ultrasound
For most ultrasound exams no preparation is needed. However, if the organs in your abdomen are being evaluated, you may be instructed not to eat or drink after midnight or 8 hours prior to your exam. You may also be asked to drink several glasses of water 1 hour before your test and to avoid urinating, so that your bladder is full for part of the exam. You should wear loose comfortable clothing. You may be asked to change into a hospital gown.
Please visit or call any of our New Mexico locations to schedule a consultation.
How Do I Get My Ultrasound Results?
After your ultrasound is over, the images will be evaluated by one of our board-certified Radiologists with expertise in ultrasound imaging. A final report will be sent to your doctor, who can then discuss the results with you in detail. Should you have any questions regarding your Ultrasound exam, we will be happy to discuss them with you.
Learn More About Different Types of Ultrasound We Offer
Pregnancy Ultrasound – a women’s imaging procedure to identify the sex of their child, and track fetus development.
Vascular Ultrasound – we use high frequency, non-invasive sound waves to evaluate organs, arteries and the abdomen.
Diagnostic Mammography – a diagnostic procedure for women showing significant breast cancer symptoms.
Breast Ultrasound – produces a sonogram to diagnose symptoms found on a physical exam. Often done alongside a mammogram.
Ultrasound Core Biopsy – a minimally invasive procedure to obtain internal tissue for diagnosis.
What Is the Difference Between an Ultrasound & a Sonogram?
These terms, sonogram and ultrasound, are often used interchangeably which can create some confusion. But there are slight technical differences between the two. An ultrasound is the procedure that creates a sonogram, which is the actual image of your fetus or body tissue.
A sonogram is usually a grainy, black and white image. It is generated by the high frequency sound waves produced from the ultrasound equipment.
Where Can I Get A Pregnancy Ultrasound in New Mexico?
- Alamogordo Ultrasound Locations
- Albuquerque Ultrasound Locations
- Farmington Ultrasound Locations
- Santa Fe Ultrasound Locations
How Does Ultrasound Work?
Certain crystals in the probe known as piezoelectric crystals convert electrical energy into sound energy. These sound waves produced by a probe are transmitted and reflected back from the tissue and fluid interfaces of the fetus, amniotic fluid and placenta.
Two different transducers are used to visualize superficial and deep organs. Higher frequency transducers yield high resolution images whereas low frequency transducers penetrate tissues more effectively. In early frequency 5 to 10 megahertz vaginal transducer is used because the early fetus is close to the transducer. In the second trimester a 4 to 6 megahertz abdominal transducer is used to produce precise images while by the third trimester a lower frequency 2 to 5 megahertz transducer maybe needed for sound waves to penetrate tissue, but the obtained resolution maybe low.
Is Ultrasound Safe to the baby?
American Institute of Ultrasound in Medicine, 2010 has concluded that no causal relationship could be demonstrated between diagnostic ultrasound and recognized adverse effects, so it is usually recognized as safe. In addition to that, all ultrasound machines have thermal index and mechanical index that detects the temperature and pressure. However, sonography should be performed only for a valid medical indication and only by those trained to recognize medically important conditions such as fetal anomalies.
The use of sonography for non-medical purpose such as “keepsake” is not recommended by the Food and Drug Administration (FDA).
Why is ultrasound done in the first trimester?
- To confirm intrauterine pregnancy
- To evaluate ectopic pregnancy (Fetus is present outside of uterus)
- To find out the cause of vaginal bleeding
- To evaluate lower abdominal pain
- To estimate gestational age
When performed with quality and precision, ultrasound alone is more accurate than a “certain” menstrual date for determining gestational age in the first and second trimesters (≤ 23 weeks), and it is the best method for estimating the delivery date.
- To check for twins
- To check heartbeat (cardiac activity) of the baby
- To assist in taking a sample of tissue surrounding the baby inside the uterus which may help to check for certain types of cancer and to remove intrauterine device if present.
- To assess fetal anomalies such as anencephaly (absence of brain in baby) in high risk patients.
- To evaluate masses or abnormalities in the uterus of the mother.
- To test for genetic diseases in the fetus.
- To evaluate a type of disease known as Gestational Trophoblastic disease in the mother.
What Information Is Gleaned From First Trimester Ultrasound?
- Gestational sac size, location and number
- Embryo and/or yolk sac identification
These structures develop to form the future baby and the tissue surrounding it, so the absence of these structures despite a positive urine dipstick test for pregnancy suggests a abnormal condition such as Gestational Trophoblastic Disease.
- Crown-rump length
This is the length of the baby from head to the buttocks and is used to calculate the age of the fetus (gestational age).
- Fetal number (to check if there are twins)
- Embryonic/fetal cardiac activity
- Assessment of embryonic/fetal anatomy appropriate for the first trimester
To check if the baby’s heart, brain, limbs, head and to detect any abnormalities.
- Evaluation of the maternal uterus, adnexa and cul-de-sac, to check mother’s uterus and surrounding structures to ensure a safe environment for both mother and the child.
- Evaluation of fetal nuchal region, to check the transparency of the baby’s skull. It can be used to detect conditions such as Down’s syndrome in the baby.
Why Is Ultrasound Done In The Second And Third Trimester?
In addition to the above points, the indications for second and third trimester are the following:
- To estimate the fetal weight. Abnormally large babies, a condition known as Macrosomia can cause problems during the delivery and may put the mother at risk. On the other hand, a small baby signifies growth restriction, both of these conditions should be appropriately checked for and intervened on time to avoid any consequences.
- To check fetal presentation (to see the position of the baby in the uterus )
- Suspected placenta previa (Placenta grows in the opening of the uterus (cervix) and may cause severe bleeding and causes risk to both the mother and baby)
- Premature rupture of membranes
Cases where water breaks before the date of delivery:
- Preterm labor
Cases where labor starts early before the baby is matured fully (before 37 weeks of pregnancy):
- During amniocentesis: a procedure to check for cells in the amniotic fluid in order to check for genetic defects in the baby such as Down’s Syndrome.
- While performing cephalic version
Baby is supposed to be upside down in the uterus, if it lies transversely or lies with legs downwards, either surgery has to be done, normally delivery is either impossible/difficult or baby has to be manually turned downwards with baby’s head facing the opening of uterus which is called cephalic version.
- To check for amount of fluid present around the baby (Amniotic fluid) and to determine the Amniotic Fluid Index(AFI)
Excess or deficient fluid is not normal and is known as polyhydramnios and oligohydramnios respectively. Too much fluid signifies abnormalities within the fetus while too little fluid may cause clubfoot in fetus, growth restriction or abnormalities in the baby’s lungs.
Doppler Ultrasound aka Vascular Ultrasonography
When sound waves strike a moving target, the waves are reflected back in accordance to speed and direction (velocity) of that moving target, this phenomenon is known as Doppler shift. We can use this principle to evaluate flow within blood vessels.
Use of Vascular Ultrasonography (Doppler) in Pregnancy
- To check blood flow to the baby from the mother – A blood vessel which is known as Umbilical artery carriers blood from mother to the baby in order to supply oxygen and nutrients to the baby. The waveform of blood flowing in it is calculated and determined if it is normal or abnormal.
- To check the blood flow in the heart of the baby – Fetuses exposed to certain medications are at risk for closure of a blood vessel known as Ductus arteriosus, therefore close monitoring is required
- To check the blood flow in the Uterus of the Mother – Early in pregnancy blood flow is around 50ml/min and rises to 500 to 750ml/min later in pregnancy. Certain Doppler waveforms can be used to identify risk of development of conditions such as high blood pressure in the mother which can lead to life threatening condition known as Eclampsia and growth restriction in the baby.
- To check blood flow to the head of the baby
Blood vessels in the skull of the baby can be investigated using Doppler to identify fetal anemia and to evaluate growth-restriction.
Why is ultrasound used in non-pregnant women?
- To check for the diseases of the ovaries
- To investigate bleeding in post-menopausal women
- To investigate excessive bleeding during menses
- To monitor precursors of ovum (female egg) known as follicles, their number and growth to prepare for IVF (In-vitro Fertilization)
- To screen for ovarian Cancer