7 Week Ultrasound

The ultrasound at the 7th week of pregnancy shows us an insight of the growth and the development of the embryo. All of the organs start to develop. Followed by the embryo measures, we can figure out the growth progress over the past period. At the 7th week of pregnancy, you can choose if you want trans-abdominal or trans-vaginal ultrasound examination. It is proven that the trans-vaginal ultrasound examination is more accurate during the 7th week of pregnancy, but both ways are in use at this stage. Your sonographer will give you an advice on which method you should choose.

Reasons for Doing 7 Week Pregnancy Ultrasound

  • If you recently have had a miscarriage and have conceived again. During an ultrasound examination, your doctor will determine the condition of the embryo and its location. It will help with making a conclusion about the risk of miscarriage.
  • If you want to confirm the gestational age of the embryo, you can calculate the number of weeks of pregnancy using ultrasound.
  • If you want to check if the gestational sac is located within the uterus and to exclude the ectopic pregnancy. Ectopic pregnancy can be a very dangerous condition for a woman’s life, so it is important to determine if the sac is at the proper place.
  • To determine if the embryo’s heart is beating. If the fetal heartbeat is present at this time, the risk of miscarriage at this stage is reduced to approximately 5%.
  • To confirm the viability of the pregnancy.
  • To determine whether it is one or two embryos together with the gestational sacs.
  • If you are bleeding or having any unusual pain. The bleeding and pain may be a sign of possible miscarriage, so we should be very careful about that.
  • To determine the cause and the source of any bleeding, because the pregnant mother may lose blood and get anemia. Pregnant women are prone to anemia and therefore we should prevent any risk factors for getting one.
  • To make sure that the size of the embryo is appropriate for its gestational age.
  • To check the conditions of the uterus, ovaries, and the fallopian tubes.
  • If you were having irregular menstrual cycle history, you can check if the embryo’s development is in relation to your menstrual history.

How Will My 7 Weeks Pregnant Ultrasound Be Done?

Your ultrasound scan will be done by highly qualified professional. During your scan, the doctor will explain the findings and, following your scan, will give you scan images and detailed report. An ultrasound scan typically takes approximately 10 minutes. The procedure is painless, regardless of whether it is a trans-abdominal or trans-vaginal examination. It can be a little bit unpleasant, due to the gel used during the examination which can be a little cold. When the ultrasound probe goes on your stomach, you can feel uncomfortable if your bladder is fully filled.

As we mentioned above, there are two methods of the examination, the trans-abdominal and the trans-vaginal. During the trans-abdominal examination, a sonographer uses a transducer which is bigger than the transducer for trans-vaginal examination. He will slide the apparatus over your tummy. Your bladder should be full, so the uterus could lift up and show the embryo which will be seen more clearly.  During the pregnancy, the uterus will rise together with the amount of amniotic fluid, therefore, at the later stages of the pregnancy, your bladder will not have to be fully filled for an examination.

During the trans-vaginal examination, a sonographer will insert a transducer into your vagina and   slowly move the transducer. In this case, there are no obstacles such as abdominal muscle layer and pictures are clearer. Most sonographers agree on the state that the trans-vaginal ultrasound examination allows more accurate data at the 7th week of a pregnancy.


Trans-vaginal ultrasound examination.

What Can I See and Hear On 7 Week Ultrasound?

At this stage, we can see the early separation of the embryo from the yolk sac and measure the Crown Rump Length (CRL). This means that the measurements are taken from the top of the embryo’s head to its bottom.  Using this measurement, we can calculate how many weeks and days you are pregnant. This measurement gives us an insight into the growth and development of the embryo, as well. CRL and the gestational age are closely linked with each other until the end of the first trimester. The embryo’s length is approximately 5-12 mm long and the weight is less than 1 gram. The length of the embryo depends on individual factors.

At this stage, using trans-vaginal ultrasound can clearly show the heartbeats of the embryo’s heart. Between the 6th and 7th week of gestation, the average number of the heart beats per minute was 90-110 beats per minute (BPM), but during the 7th week, this rate increases to 150-160 BPM. The reason for this is intensive growing of the embryo’s body and brain. The larger body and brain needs more oxygenated blood, so the heart pumps more blood at a faster rate.

This is also the week when the liver begins with the development and starts producing red blood cells. The appendix and pancreas begin to form, as well. A part of the growing intestine connects to the umbilical cord for carrying oxygen and nutrients. It is still too early to determine the gender of the fetus. We can see if the kidneys are in a proper place.

The cartilages are forming into limb buds and the hands, foot, fingers and toes are preparing for growth.

The inner ears continue with their development as eyes do as well. The parts of the face are forming, and we can identify the jaw, mouth, nose and eyes.


Trans-vaginal sonogram


Trans-abdominal sonogram

What Is the Accuracy Of 7 Week Ultrasound?

The accuracy of a 7th-week ultrasound isn’t absolute. It doesn’t give us an absolute proof of the dates, gender, size or the unborn baby’s status. Even if the sonographer is very experienced, the embryo may be stretched out, curled up, or it can take a position that makes it difficult for the sonographer to fully estimate their size. The best time to do ultrasound examination is usually between 8 to 11 weeks of gestation as compared to a 12th week, since we can get more accurate results from the earlier scans.


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