Ultrasound in-office procedure
During an ultrasound, your doctor or a skilled technician uses a plastic transducer to transmit high-frequency sound waves through your uterus. These sound waves send signals back to a machine that converts them into images of your baby. The test doesn’t hurt, although gel (used to guide the transducer on the stomach) may feel cold and be messy. You should wear two-piece clothing to allow easy access to your tummy. Note that it will be hard to see much during the first few weeks of pregnancy, but a clearer photo will come around 13 weeks, which is the ideal time to share your exciting news.
How do ultrasound scans work?
An ultrasound scan uses high-frequency sound waves to create images of the inside of the body. It is suitable for use during pregnancy. Ultrasound scans, or sonography, are safe because they use sound waves or echoes to make an image, instead of radiation.
Ultrasound scans are used to evaluate fetal development, and they can detect problems in the liver, heart, kidney, or abdomen. They may also assist in performing certain types of biopsy. The image produced is called a sonogram.
Higher frequencies provide better quality images but are more readily absorbed by the skin and other tissue, so they cannot penetrate as deeply as lower frequencies. Lower frequencies penetrate deeper, but the image quality is inferior.
How many ultrasounds do you need?
This varies based on the woman and her pregnancy. Here are some ultrasound exams you might have while expecting. Early Pregnancy Ultrasound (6-8 Weeks) Your first ultrasound, also known as a sonogram, may take place when you’re around 6 to 8 weeks pregnant. However, some doctors only conduct this exam if you have certain high-risk pregnancy conditions. These include bleeding, abdominal pain, and history of birth defects or miscarriage.
Early Pregnancy Ultrasound (6-8 Weeks)
This first exam may be conducted trans-vaginally so doctors get a clearer picture of your baby. In this case, your OBGYN will place a thin wand-like transducer probe—which transmits high-frequency sound waves through your uterus—in your vagina. The sound waves bounce off the fetus and send signals back to a machine that converts these reflections into a black and white image of your baby.
At 6 weeks’ gestation, it’s possible to see the baby’s heartbeat. Your practitioner will also predict your baby’s due date, track milestones, determine the number of babies in the womb, and see whether you have an ectopic pregnancy.
Ultrasound (10-13 Weeks)
Those who forgo the 6-8 week ultrasound might have a”dating ultrasound” around weeks 10-13. This gives parents the same type of information: due date, your baby’s “crown-rump length” (measurement from head to bottom), the number of babies in the womb, and fetal heartbeat.
Nuchal Translucency Ultrasound (14-20 Weeks)
Between 14 and 20 weeks, you may also have a nuchal translucency (NT) test to check for Down syndrome and other chromosomal abnormalities,.Women whose screening test revealed a potential problem, who are 35 or older, or who have a family history of certain birth defects should consider it. Doctors will measure hormones and proteins with a blood test, and they’ll also gauge the thickness at the back of the baby’s neck with an ultrasound. A thicker neck may indicate an increased risk for birth defects like Down syndrome and trisomy 18.
Anatomical Survey (18-20 Weeks)
This detailed ultrasound, generally between weeks 18 to 20 of pregnancy, lasts 20 to 45 minutes if you’re having one baby and longer if you’re having multiples. This is the most thorough checkup your baby will have before she is born.
The doctor will check your baby’s heart rate and look for abnormalities in her brain, heart, kidneys, and liver, She’ll count your baby’s fingers and toes, check for birth defects, examine the placenta, and measure the amniotic fluid level. And she’ll probably be able to determine your baby’s sex, although it’s not a slam dunk; an experienced tech gets it right more than 95 percent of the time. (If you don’t want to know your baby’s sex, let her know ahead of time.)
Fast facts on ultrasound scans
- Ultrasound scans are safe and widely used.
- They are often used to check the progress of a pregnancy.
- They are used for diagnosis or treatment.
- No special preparation is normally necessary before an ultrasound scan.
The transducer, or wand, is normally placed on the surface of the patient’s body, but some kinds are placed internally. These can provide clearer, more informative images. Examples are: an endovaginal transducer, for use in the vagina an endorectal transducer, for use in the rectum a transesophageal transducer, passed down the patient’s throat for use in the esophagus Some very small transducers can be placed onto the end of a catheter and inserted into blood vessels to examine the walls of blood vessels.