How Accurate Is an Ultrasound at Six Weeks?

If you think you might be pregnant—especially if the pregnancy was unplanned—you may be feeling a mixture of emotions and questions. Whether you’re seeking confirmation or simply need clarity, an early ultrasound can be a helpful next step. At Open Arms Real Choices Clinic, we offer free, limited obstetric ultrasounds to support you with accurate information in a compassionate and confidential setting.

Understanding Early Ultrasounds

Ultrasounds are a safe and effective tool commonly used in prenatal care. A limited obstetric ultrasound can confirm a pregnancy, estimate how far along you are, and ensure that the pregnancy is developing as expected.

While ultrasounds can be performed as early as six weeks, it’s important to understand what can—and can’t—be seen at this stage. At six weeks of gestation, the baby is very small (about the size of a pea), so visualizing and measuring the baby can be more challenging than in later weeks. Even so, a six-week ultrasound can often detect:

✔ A developing gestational sac
✔ A fetal pole (early development of the embryo)
✔ A heartbeat (in many cases)
✔ Whether the pregnancy is located in the uterus (not ectopic)

How Accurate Is a Six-Week Ultrasound?

Ultrasound is one of the most accurate ways to estimate gestational age and determine a due date, especially when done early in the pregnancy. The earlier the ultrasound, the more reliable it is for dating the pregnancy. This is because every baby grows at about the same rate in the early stages of development.

That said, due dates are always estimates. At six weeks, small differences in measurements—just a millimeter or two—can shift the estimated due date by several days. If your cycle is irregular or you’re unsure about when your last period started, the ultrasound will likely provide a more accurate gestational estimate.

Why Would My Due Date Change?

Due dates are typically calculated based on the first day of your last menstrual period (LMP), assuming a regular 28-day cycle with ovulation occurring around day 14. However, many women do not have a predictable cycle, which can make dating less reliable. An early ultrasound helps bridge that gap, giving you and your care team a clearer picture of your pregnancy’s timeline.

Why Are Early Ultrasounds Performed?

A limited obstetric ultrasound performed at or around six weeks is typically used to:

• Confirm a pregnancy

• Ensure the pregnancy is located in the uterus (not ectopic)

• Measure the baby’s growth

• Estimate gestational age and calculate a due date

• Identify if there is more than one baby

What to Expect at Your Ultrasound Appointment

Ultrasounds are safe and non-invasive. Depending on how far along you are, the scan may be performed abdominally or transvaginally (especially in early pregnancy).

Here’s how the process works:

✔ A technician will apply a special gel to the ultrasound device (transducer).
✔ Sound waves are sent into the uterus and reflected back to create images.
✔ These real-time images help our medical team assess your pregnancy’s progress.

If you are eligible for an ultrasound at Open Arms Real Choices Clinic, our licensed professionals will guide you through every step and explain what the images show. You’ll also receive a copy of your results and support for next steps.

Compassionate Support Every Step of the Way

If you suspect you are pregnant or have taken a test and want confirmation, we’re here to help. At Open Arms Real Choices Clinic, our caring team provides:

• Free lab-quality pregnancy testing

• Limited obstetric ultrasounds (if medically appropriate)

• Pregnancy options counseling

• STI testing and treatment

• Ongoing support, classes, and referrals

You don’t have to figure everything out on your own. Whether you’re looking for answers, considering your options, or just need someone to talk to, we’re here for you.

📅 Schedule an appointment today: realchoicesclinic.com/make-an-appointment
📍 Visit us at: 8056 N. Wayne Drive, Hayden, ID 83835
📞 Call us at: 208.667.5433