If you've recently found out you are pregnant, you may be waiting on pins and needles for your first ultrasound to get a glimpse of your growing baby. Commonly known as a dating scan, the 7-week ultrasound is used to confirm your pregnancy, measure the size of your baby, and provide an estimated due date for your pregnancy. Knowing what to expect on this special day can help you prepare for the appointment and give you something to look forward to.
Preparing for Your 7-Week Ultrasound
In the first trimester, ultrasounds are generally performed between weeks 6 to 8. The ultrasound is performed by an ultrasound technician (sonographer), or your obstetrician.
Because your baby is tiny at this stage of pregnancy, your healthcare provider may ask that you have a full bladder for the ultrasound. If your provider has asked you to arrive with a full bladder, empty your bladder two hours before the exam. Then, consume two to three 8-ounce glasses of water an hour before the test.
You can bring a support person to the ultrasound, such as your partner, a family member, or a friend. Consider if you'd like them to take notes during your appointment so you can remember everything the doctor says, or hold your hand during the scan. Many facilities discourage children from attending ultrasound appointments, so you may want to arrange childcare for any children you have at home.
What to Expect at Your 7-Week Ultrasound
Depending on the type of ultrasound you are having (e.g., transvaginal, abdominal), you may be asked to change into a hospital gown. This usually isn't necessary for abdominal ultrasounds, but it can be helpful to wear two-piece, loose-fitting clothing so the ultrasound technician can easily access your abdomen.
After the ultrasound, your healthcare provider will meet with you to check in on your health and ask about any pregnancy symptoms you are experiencing, such as nausea or fatigue. It's a good idea to prepare a list of questions you may have for your provider ahead of time.
Different Types of Ultrasound
At 7 weeks gestation, your baby is about the size of a blueberry, at 0.5 inches long. Seeing your little one on the black and white screen for the first time can be an unforgettable experience, but at this stage your baby is so small that it can be difficult to see much besides their beating heart.
There are two types of ultrasounds performed at this stage in pregnancy:
- Transvaginal ultrasound. Because your baby is so tiny at this stage, a transvaginal ultrasound may be the best way to get a clear picture. A small wand (transducer) will be inserted into your vagina, similar to the way you insert a tampon. Sound waves are sent through the transducer to produce pictures of your internal organs and growing baby.
- Abdominal ultrasound. Some practitioners and ultrasound facilities perform abdominal ultrasounds at 7 weeks. The doctor or ultrasound technician will place a small amount of gel on your abdomen, which helps the transducer produce clear images of your baby. A small amount of pressure may need to be applied to your belly in order to get the best views, but this should not be painful.
What You Will Learn During the Ultrasound
During your ultrasound, you should be able to see your baby, which may look like a small blob with a rapidly beating heart, on the ultrasound screen. The yolk sac, which at this stage in the pregnancy provides your baby with nourishment and produces cells that later become the umbilical cord, reproductive organs, and blood cells, may be visible. The 7-week ultrasound helps your healthcare provider:
- Assess the baby's growth
- Check the baby's position in the uterus
- Check the health of your uterus, fallopian tubes, and ovaries
- Confirm the presence of your baby's heartbeat
- Determine if there is one baby or multiple babies
- Ensure the baby is in your uterus and is not an ectopic pregnancy (e.g., in fallopian tubes)
- Examine the amount of amniotic fluid you have
- Provide an estimated due date
The ultrasound technician or doctor will probably print out an ultrasound picture for you to take home as a keepsake to share with family and friends or add it to your baby book.
Baby's Heartbeat at 7 Weeks
By about 6 weeks gestation, a transvaginal ultrasound should be able to detect a baby's heartbeat. The average fetal heart rate at 7 weeks is between 90 to 110 beats per minute. Hearing your baby's heartbeat for the first time is an unforgettable pregnancy milestone, and you may be able to hear it at your 7-week ultrasound.
If you can't hear the heartbeat at this ultrasound, don't worry. Though a baby's heartbeat begins at the end of the 4th week of gestation, you may not be able to hear it until 8 weeks or later. You should, however, see a rapid fluttering movement on the ultrasound screen. That's your baby's heart beating.
Fetal Development at 7 Weeks
At 7 weeks gestation, your baby is growing rapidly. This week, your baby's physical development includes:
- Face: Your baby's nose, eyes and ears are beginning to grow and take shape.
- Head and brain: At this stage, your baby's head is large (comparatively to the rest of them) and their brain is growing an astonishing 250,000 neurons a minute.
- Umbilical cord: The tube that joins your baby and the placenta to provide the baby with oxygen and nutrients, and help eliminate waste, begins to form.
- Webbed hands and feet: Your baby's hands and feet at this stage look like little webbed paddles.
It is too early to detect a baby's sex via ultrasound at 7 weeks pregnant. Most expectant parents can expect to confirm the baby's sex during the anatomy scan that takes place in the second trimester around 18 to 20 weeks. If you want to know your baby's sex sooner, talk to your healthcare provider about the non-invasive prenatal test (NIPT). Done at about 10 weeks, the NIPT analyzes small fragments of DNA circulating in the pregnant parent's blood to screen for potential genetic abnormalities in a growing baby.
Diagnostic Screening
Major diagnostic tests are performed later in the first trimester and second trimester. At 7 weeks, your healthcare provider will use the ultrasound to detect your baby's heartbeat and measure them from crown to rump to provide an estimated due date. If you have specific diagnostic concerns, talk to your healthcare provider about diagnostic tests and when you can expect to have them.
Understanding Your Ultrasound
Ultrasounds can be an exciting time in pregnancy, especially the first time you see your growing baby. By 7 weeks, you should be able to get the first glimpse of your baby's heart and have a confirmation of your expected due date. Talk to your healthcare provider about any questions you have about what you saw on the ultrasound, and any other questions you may have about how to best support your health and your growing baby throughout your pregnancy.
