You've probably stared at that plastic stick until your eyes crossed, and now the reality is setting in. You’re pregnant. But it’s early. Like, really early. Your doctor or a private clinic mentions a six week scan: what to expect starts with a bit of a reality check—it’s not going to look like a baby yet. Honestly, it looks like a flickering grain of rice. Maybe a bean if you’re lucky.
Waiting for this appointment feels like a lifetime. You’re checking for spots every time you go to the bathroom. You’re Googling every cramp. You want certainty, but at six weeks, certainty is a sliding scale. This scan, often called a viability scan or a dating scan, is the first real bridge between a positive test and a clinical reality. It’s a high-stakes moment for your heart, yet medically, it’s a very simple data-gathering exercise.
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The Transvaginal Reality
Let’s get the awkward part out of the way immediately. At six weeks, your uterus is still tucked deep behind your pelvic bone. An abdominal ultrasound—the kind where they rub gel on your belly like in the movies—usually won't show much of anything this early. You’re almost certainly going to get an internal scan.
The sonographer uses a lubricated probe. It’s not painful, but it is "pressury." This is how they get close enough to the gestational sac to see what’s actually happening inside. If you go to a clinic and they insist on doing it over the skin, don't be surprised if they "can't see anything" and send you into a spiral of panic. Usually, it’s just because the tech isn't right for the timing.
What is the sonographer actually looking for?
They aren't looking for fingers or toes. They’re looking for three specific things to confirm this pregnancy is moving in the right direction.
First, the gestational sac. This is the fluid-filled "house" where the embryo lives. If this is empty, it might just be too early, or it could be an "anembryonic pregnancy."
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Next is the yolk sac. This looks like a tiny white circle inside the bigger circle. It’s the primary source of nutrients for the embryo before the placenta takes over. Seeing a yolk sac is a massive milestone; it confirms the pregnancy is "true" and located in the right place, ruling out most ectopic concerns.
Finally, the fetal pole. This is the actual embryo. At six weeks, it’s about 5mm to 9mm long. Small. Tiny. But if the timing is right, this little speck will have a rhythmic flicker.
The Heartbeat: Will you hear it?
Probably not. You’ll see it.
The "heartbeat" at six weeks isn't actually a fully formed heart with valves and chambers. It’s a group of specialized cells that have started a spontaneous electrical pulse. On the screen, it looks like a tiny, fast-twitching pixel. It’s incredibly fast, usually between 100 and 120 beats per minute.
If you don't see it? Take a breath. It doesn't automatically mean bad news.
Ovulation is an imprecise science. You might think you’re 6 weeks and 2 days based on your last period, but you might have ovulated late. You could actually be 5 weeks and 4 days. At that stage, a heartbeat often hasn't started yet. Most doctors, like those at the American College of Obstetricians and Gynecologists (ACOG), will suggest waiting 7 to 10 days and scanning again before making any definitive calls. The "wait and see" period is agonizing, but it's common.
Why get a scan this early anyway?
Most standard healthcare systems, like the NHS in the UK, don't offer a scan until 12 weeks. So why do people seek out a six week scan: what to expect?
- History of loss: If you’ve had a miscarriage or an ectopic pregnancy, your doctor will want to see where that egg landed as soon as possible.
- Pain or bleeding: Spotting is terrifying. A scan can check for a subchorionic hematoma—a small pool of blood behind the pregnancy—which is often harmless but causes bleeding.
- IVF or Fertility treatments: These pregnancies are monitored from day one with extreme precision.
- Peace of mind: Let’s be real. Living in "Limbo Land" for three months is hard.
There are downsides to scanning early, though. If you go too soon and see nothing, you’ve traded your "anxious wait" for a "terrified wait." The "behind-the-scenes" development between week five and week seven is massive. A few days can be the difference between an empty-looking sac and a visible heartbeat.
Hidden details: Twins and Tilted Uteruses
Sometimes you get a surprise. If there are two gestational sacs, you’ll know right now. This is the stage where "Vanishing Twin Syndrome" is sometimes identified—where two sacs start, but only one develops. It's a heavy thing to process, and it's more common than people realize.
Also, if you have a "retroverted" or tilted uterus, the scan might be even harder to see. Your uterus just leans back toward your spine instead of forward toward your belly. It’s a normal anatomical variation, like being left-handed, but it makes the sonographer's job a bit trickier this early on.
The "Empty Sac" Scare
The most common "bad" result at a six-week scan isn't a miscarriage; it's a "pregnancy of unknown viability."
Basically, the sonographer says, "We see a sac, but no embryo yet."
This happens constantly. Because implantation can happen later than expected, your "six weeks" is just a guess based on a calendar. If the sac is under 25mm and there's no embryo, most clinics won't call it a loss. They’ll make you come back in a week. That week will be the longest week of your life. Eat well, try to sleep, and stay off the forums. Every pregnancy is different.
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Practical Next Steps
If you are heading into your appointment, here is how to actually prepare for the reality of the room:
- Drink some water, but don't overdo it. For an internal scan, an empty bladder is actually better. If they try an abdominal scan first, they might want it full. Wear layers so you can easily strip from the waist down.
- Bring a partner or friend. Even if everything is perfect, the emotional rush is a lot to handle alone. If the news is "let's wait and see," you'll want someone else to listen to the doctor's instructions because your brain will likely fog up.
- Ask for the Crown-Rump Length (CRL). This is the measurement of the embryo from top to bottom. It is the most accurate way to date a pregnancy in the first trimester. Write it down.
- Check your progesterone levels. If you’re scanning because of spotting, ask your doctor if a blood test for progesterone or hCG doubling times is appropriate alongside the ultrasound.
- Manage your expectations for the "photo." You’ll get a thermal printout. It will look like a grey blob with a crosshair on it. You won't be able to tell what's what once you get home, so ask the sonographer to point out the yolk sac and the embryo while you're looking at the big screen.
- Schedule your follow-up. Regardless of what is seen, your next major milestone is the 10-12 week mark for NIPT testing or the nuchal translucency scan. If your six-week scan was "borderline," book that follow-up for 10 days out immediately to avoid more waiting.
Early pregnancy is a lesson in losing control. The six-week scan is your first glimpse into that world. It’s a tool for safety and dating, but it’s rarely the "perfect" cinematic moment people expect. It’s technical, it’s a bit clinical, and it’s just the very beginning of the journey.