A 12-week ultrasound allows your healthcare provider to check how your baby is developing and to look for conditions like Down syndrome . With this scan, your doctor can also determine your due date and the number of babies you are pregnant. Your baby's external genitalia are well developed, so your doctor can also determine the sex of your baby.
Week 12 is the end of the first trimester of your pregnancy, when all of your baby's major organs and systems are forming. By 12 weeks, the baby's organs and body systems are fully formed. In most cases, a 12-week ultrasound may be the first time you see your baby.
What is ultrasound?
Ultrasound, or ultrasound , is an imaging technique that uses the energy generated by sound waves to create images of the inside of your body. During an ultrasound exam, a transducer sends sound waves to your body, which are reflected to take readings. These waves then hit tissues, fluids, or bones within the body. The signals are returned and create images that can help diagnose conditions or take action within the body.
A 12-week ultrasound allows your healthcare provider to see your baby in the womb. However, the ultrasound may not go away after exactly 12 weeks. Ultrasound at 12 weeks is common, but not standard because there hasn't been enough development at this stage for your healthcare provider to be able to visualize your baby's limbs and organs in detail.
In many cases, an ultrasound is done in the first trimester to confirm the pregnancy and the fetal count (as the baby is called up to eight weeks) and to get an idea of the overall development of the baby.
Although your healthcare provider will be limited in what you can see during this early stage of pregnancy, a 12-week ultrasound can be used to:
- Calculate your gestational age and due date
- Detection of specific disorders such as Down syndrome
- Count the number of fruits
- Check your child's heart rate
- Exclude ectopic pregnancy (when a fertilized egg implants outside the uterus)
Although most women generally have two ultrasounds, one around 12 weeks and the other around 20 weeks, your healthcare provider can only do one. If only one ultrasound is done, around the 20th week of pregnancy, to:
- Check the position, movement and heart rate of the fetus.
- Calculate the size and weight of your child
- Check the amount of amniotic fluid in the uterus.
- Find the location of the placenta
- Confirm the amount of fruits
- Evaluate birth defects or abnormalities
Ultrasound screening of occipital transparency
The screening test for Down syndrome and two chromosomal abnormalities, trisomy 13 and trisomy 18, used during this stage of pregnancy is called a combined test. It includes a blood test and measurement of the fluid on the back of the baby's neck (occipital transparency) using an ultrasound.
However, the combined screening test is not a diagnostic test, which means that it cannot tell you if your child has Down syndrome, trisomy 13, or trisomy 18. Instead, the screening test gives the possibility that the child have one of these genetic disorders …
Probability or probability is based on three criteria: your age, information from the ultrasound, and a blood test. Screening test results can alert you and your healthcare provider that your child is at increased risk for one of these chromosome abnormalities, or they can confirm that your child is at lower risk for these conditions.
A positive result, which indicates an increased risk, does not mean that your child has problems, and a negative or normal result (which shows a reduced risk) does not mean that the child will not have a chromosome abnormality.
The detection rate at screening in the first trimester is approximately 96% for pregnancies in which the baby has Down syndrome and slightly higher for pregnancies with trisomy 13 or trisomy 18. An occipital translucency ultrasound can be done without a blood test, but the detection rate drops to about 70%.
What happens during a 12 week ultrasound?
Your healthcare provider will most likely perform a transabdominal ultrasound , which transmits waves through your abdomen. In some cases, a transvaginal ultrasound may be done to obtain more direct or detailed images. The scan usually takes 20 to 30 minutes.
During a transabdominal ultrasound, you will be asked to lie on the exam table, either in the treatment room or at your healthcare provider's office, so that the abdomen is exposed from the ribs to the thighs. You may be asked to come to your appointment with a full bladder, which will create a window into the uterus.
When the test is ready to begin, your healthcare professional will apply an ultrasound gel to help guide the sound waves to your skin. This will help improve the quality of ultrasound images. Then your doctor will move the portable ultrasound probe back and forth across your abdomen with a slight amount of force. It shouldn't be painful, although you may experience some discomfort associated with positioning.
They may stop at specific areas of your abdomen to take specific photographs or measurements. Measurements will be taken on different parts of your baby's body and your uterus. You can make a short record of your child's heart movement.
During a transvaginal ultrasound, you may be asked to undress below the waist or even remove your clothing and change into a medical gown. Unlike a transabdominal ultrasound, you will be asked to empty your bladder before the exam begins.
When you are ready to begin the test, you will be asked to lie on the exam table with your feet resting on the stirrups, as if you were doing a pelvic exam. A rod-shaped tube covered with a protective sheath will be inserted through the vagina for an internal view of the uterus. It doesn't have to be painful, but you may feel discomfort like a pelvic exam.
You may receive initial information about your baby during an ultrasound, but you will likely receive a detailed report later when seen by a radiologist. Then your healthcare provider will discuss the results with you.
Although the above describes a standard 12-week ultrasound or a first trimester ultrasound, your healthcare provider may have reasons to request additional tests. If you experience bleeding or other worrisome symptoms, your healthcare provider may order a limited ultrasound to quickly identify the specific problem. This can happen at any stage of pregnancy.
You may also be asked to have a specialized ultrasound or more regular scans. This ultrasound is done in the same way as a 12-week ultrasound, but it can examine the fetus in more detail, using 3D images, or more frequently throughout the pregnancy.
Get the word of drug information
Many expectant parents are looking forward to their first ultrasound. It can give you a first impression of your baby and strengthen your bond with your unborn baby. Most pregnancies have two ultrasounds, but don't be surprised if you only get one, or more in high-risk pregnancies. Resist the urge to have a non-medical ultrasound as a reminder of your pregnancy.