The 9-week ultrasound often serves as the first official opportunity to look inside the uterus after a positive pregnancy test, confirming early development. The primary goals of this early appointment are to confirm the pregnancy is located correctly within the uterus, assess viability, and accurately determine the gestational age. Understanding the images and measurements obtained during this scan provides reassurance about the progression of the pregnancy.
Visual Landmarks: What You Will See
The ultrasound image at nine weeks will show a small, curved structure, often described as having a “gummy bear” or “bean” appearance. This structure is the embryo, which is transitioning into a fetus during this week of development. The head is noticeably larger than the rest of the body at this stage, and the body has a distinct curvature that makes the crown-to-rump measurement possible.
The developing arms and legs are visible as small limb buds, and an early form of the skeletal structure is present. Small movements of the torso or limbs may be seen, though they are too subtle to be felt by the parent at this time. Surrounding the embryo is the dark, fluid-filled circle of the gestational sac, which houses the developing pregnancy.
Within the gestational sac, a separate circular structure called the yolk sac is visible. The yolk sac provides temporary nourishment to the embryo until the placenta is fully functional. The umbilical cord, which connects the embryo to the placenta, is also forming and visible at this point.
Defining Fetal Growth: Measurements and Heartbeat
Two measurements are important during the 9-week ultrasound, as they offer key data points for dating the pregnancy and assessing development. The first is the Crown-Rump Length (CRL), which is the measurement from the top of the embryo’s head to the bottom of its torso. At nine weeks, the CRL typically falls within the range of approximately 22 to 30 millimeters, roughly the size of a large olive.
This measurement is the most accurate way to calculate the Estimated Due Date (EDD) during the first trimester. The CRL is precise because the growth rate of embryos is highly consistent at this stage, making it a more reliable indicator of gestational age than the date of the last menstrual period. The embryo’s length is expected to increase by about one millimeter per day around this time.
The second measurement is the Fetal Heart Rate (FHR), which is the primary sign of viability. At nine weeks, a healthy heart rate is typically found in the range of 150 to 180 beats per minute (bpm). The embryonic heart, which has developed four chambers, beats at a rapid rate, often twice as fast as an adult’s heart.
A strong, visible, and appropriately fast heart rate provides reassurance about the pregnancy’s progression. Once the heart rate is detected and the size is within the expected range, the chances of a successful pregnancy increase.
Interpreting the Results and Next Steps
The 9-week scan is often performed using a transvaginal approach, especially since the small structures require high resolution. This method involves inserting a specialized transducer into the vagina, allowing for closer proximity to the uterus and better visualization of the embryo. The transvaginal method is routinely used in the early weeks to ensure accurate measurements.
During the scan, parents may hear various terms used by the healthcare provider or see them on the final report. Terms like “GS” (Gestational Sac) and “FHR” (Fetal Heart Rate) refer to the main structures and viability metrics assessed. The term “EDD” (Estimated Due Date) is the expected date of delivery calculated primarily from the CRL measurement.
It is not uncommon for the embryo to measure a few days ahead or behind the gestational age calculated from the last menstrual period, but the CRL provides the definitive dating. Following the scan, the results are reviewed with the healthcare provider to ensure all measurements are within normal ranges. The findings from this scan set the reference point for all subsequent growth and dating assessments throughout the pregnancy.