6 week ultrasound: Understanding early pregnancy scans

A 6 week ultrasound isn’t considered too early. In fact, many pregnant women have their first screenings around this time. This is done to confirm pregnancy, identify the gestational age, see if it’s a single or multiple pregnancy, and rule out ectopic pregnancy or other complications.

Although it’s not considered too early to have an ultrasound, it’s important to understand that your baby is still tiny and needs time to develop. In an ultrasound 6 week fetus is often not seen as a clear shape but rather as a dark area inside the uterus with several thickened structures (yolk sac and fetal pole). So it’s important to set realistic expectations for your first screenings.

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6 weeks is an important milestone in early pregnancy. At this time, your baby is growing fast and continues developing its major systems and organs. Also, at 6 weeks, the embryo starts forming limbs.

Although it’s still very early, often, 6-9 weeks is the time when you will have your first ultrasound scans. And while this can feel incredibly exciting to see your baby for the first time, it’s also natural to experience anxiety and have lots of questions about your early checks.

In this article, we’ll walk you through the key aspects of a 6 week ultrasound to help you shape realistic expectations and reduce anxiety.

What Does Your Baby Look Like at 6 Weeks?

At 6 weeks, the embryo is still very small. The average size is around 6 mm long. It’s growing fast, but is the size and shape of a pea. The limbs are only starting to develop and are not visible. Some people compare the appearance of the baby at this stage to a tadpole with a little tail.

Why Is a 6 Weeks Pregnant Ultrasound Done?

Given the small size of the embryo, you can easily guess that a 6 week ultrasound still doesn’t show as much as you’d wish. Still, this is often around the time when first pregnancy scans are scheduled.

The main reasons to have an early scan include:

• Pregnancy confirmation – Most often, the first scans are done to confirm pregnancy. Of course, you’ve probably already done a few pregnancy tests at 15 DPO or 16 DPO. Still, it’s important to schedule a doctor visit to confirm positive test results and receive essential prenatal care.
• Gestational age confirmation – During the first scans, a doctor will assess the size of an embryo to establish or confirm the assumed gestational age. Determining gestational age early and accurately is crucial to receiving the best medical care for you and your baby through the entire pregnancy. And it’s also important for estimating the due date.
• Single or multiple pregnancy confirmation – During an ultrasound check, a doctor will locate the gestational sac and yolk sac. The number of sacs can help you detect if there is a multiple pregnancy, for example, twins or more. This is crucial to prepare an optimal medical care plan. And it’s also important for pregnancy confirmation, especially if you’ve missed your period but had a false negative or faint line test.
• Exclusion of ectopic pregnancy (or other complications) – If there is a suspicion of ectopic pregnancy or other complications, it’s also possible to have an early ultrasound scan. In fact, in this case, it can be done as early as 5 weeks.
• High-risk pregnancy monitoring – Lastly, early scans are also typical in high-risk pregnancies. For example, if there are adverse symptoms like pain or bleeding, a history of complications, or if it’s an IVF pregnancy, scanning early is crucial to detect complications early and provide proper care.

What Happens During the 6 Week Ultrasound?

Now that you know more about the reasons for having an ultrasound at 6 weeks, let’s delve into the specs of such screening.

Firstly, what kind of ultrasound can you expect to face? Normally, there are two types of scanning used in pregnancy:

Transvaginal Ultrasound

This is an imaging procedure that leverages high-frequency sound waves to create detailed images of female internal pelvic organs, such as the uterus, cervix, and ovaries. In this procedure, doctors use a wand-like transducer that’s inserted into the vagina. The procedure itself is quick and painless.

Transvaginal ultrasound tends to produce a clearer image compared to abdominal scanning, which is why it’s more commonly used in early scans when the embryo is still small and hard to see.

Abdominal Ultrasound

This is a non-invasive imaging procedure. It also leverages high-frequency sound waves to generate a picture of the internal organs, in particular, those located in the abdominal area, but it doesn’t imply an internal probe. During the abdominal ultrasound, a doctor applies a special gel to your belly and uses a transducer that moves over the abdomen to receive an image.

Typically, you shouldn’t expect to have a 6 week abdominal ultrasound. At this time, the embryo is too tiny to be clearly seen through the abdomen. Besides, transvaginal screening provides a generally clearer image that allows more accurate analysis.

Additional note: If this is your first pregnancy and you don’t know what to expect from your first screenings, learning that you need to have a transvaginal ultrasound can sound a little discomforting. However, there are no reasons for worry. This procedure is considered absolutely safe both for you and your baby. And it’s considered to be more effective for detailed views of early pregnancy.

What Can You See on a 6 Week Ultrasound?

Since 6 weeks is still rather early, it’s important that you have realistic expectations about what you can and can’t see during scanning. A normal 6 week ultrasound can show you some of the following structures:

• Gestational sac – This is a fluid-filled sac located inside the uterus that has a protective purpose. It’s one of the earliest structures formed in pregnancy and detected by an ultrasound. In the scanning image, it simply looks like a black area. Between 5 and 8 weeks, doctors locate the gestational sac to confirm an intrauterine pregnancy.
• Yolk sac – This structure is located within the gestational sac, beside the embryo. It performs two crucial functions - oxygen supply and nutrition of the fetus for its proper development. In the early scanning image, it typically looks like a small white dot inside the black area (your gestational sac).
• Fetal pole – This is the first structure of a growing embryo that can be detected in an ultrasound. It’s located next to the yolk sac and looks like a dot or a small curved shape.
• Heartbeat – At 6 weeks, your baby’s heart and cardiovascular system continue developing, forming a heartbeat. In the idealized gestational age, it’s possible to detect 6 week ultrasound heartbeat. At this time, the beating is quite fast – 90-110 beats per minute (bpm). However, it might still not be so pronounced. It’s important to remember that every pregnancy is unique and developmental milestones can fluctuate. Thus, it’s absolutely normal to detect the heartbeat later, usually after 6.5-7 weeks.
• Crown-rump length (CRL) – As you already know, at 6 weeks, it’s already possible to evaluate the gestational age based on the embryo size. This is done with the help of CRL – the measurement of the fetus’s length from the head (crown) to the bottom part of the buttocks (rump).

FAQ

Is 6 weeks pregnant ultrasound still too early?

6 weeks is still rather early in your pregnancy. At this time, the fetus is small and only starts getting its shape, which is why it might be too early to see the desired results from screening. However, a 6 week ultrasound is not considered too early. Often, you will have your first screenings scheduled around this time to confirm pregnancy and assess the gestational age.

What Does a 6 Week Ultrasound Look Like?

Most often, at 6 weeks, there is no clear shape of a baby yet. In the scanning image, you can expect to see a darker area in the uterus with two smaller, thickened areas that represent the yolk sac and fetal pole. If you have a multiple pregnancy, you can already see two or more fetuses at this point.

Should I be worried if a 6 week ultrasound heartbeat isn’t visible yet?

No. The fetal heartbeat typically forms between 5 and 6 weeks. Thus, in some cases, you may already hear the heartbeat. But it’s also okay if it’s not visible until later. The average time when the heartbeat becomes detectable is between 6.5 and 7 weeks, so it might still be too early to hear it.

Conclusion

6 weeks is an important stage in pregnancy, during which your baby is growing and developing at a rapid pace. Often, your first ultrasound screening will be scheduled around this time. It can be done if it’s medically indicated, for example, if there are any disturbing symptoms or a suspicion of an ectopic pregnancy. However, a 6 week ultrasound is also commonly done simply to confirm pregnancy, detect the gestational age, and start preparing a personalized care plan.

Despite the fact that it’s common to have the first screenings during this time, it’s important to remember that 6 weeks is still very early to see the expected screening results. That is, it’s normal if you don’t see a clear shape of your baby or don’t detect the heartbeat yet. Get patient and set realistic expectations to avoid unnecessary worries.

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