Step By Step Guide On 7 Week Pregnancy Transabdominal Ultrasound Scan | Full Protocol With Reporting

Step By Step Guide On 7 Week Pregnancy Transabdominal Ultrasound Scan | Full Protocol With Reporting

*Timestamps:
Indications - 0:00
Important Considerations - 1:09
Patient Positioning - 1:54
Probe Positioning & Scanning - 2:43
Mean Sac Diameter - 4:17
Yolk Sac Measurement - 5:44
Measuring Crown-Rump Length - 6:14
Measuring Fetal Heart Rate - 7:23
Scanning The Uterus In Transverse Plan - 12:34
Scanning The Ovaries - 13:00
Report - 14:50
Next Ultrasound Scan - 18:11

Indications for 7-Week Ultrasound:
- Confirmation of Pregnancy: To confirm intrauterine pregnancy.
- Gestational Age Assessment: To estimate the gestational age based on embryo size.
- Heartbeat Detection: To check for the presence of a fetal heartbeat.
- Multiple Pregnancy Detection: To see if there’s more than one embryo.
- Health Assessment: To assess the overall health and development of the pregnancy.
- Investigate Symptoms: Such as bleeding, pain, or unusual symptoms that could indicate a potential problem with the pregnancy.

7-Week Pregnancy: Patient Positioning
- Supine Position: The patient typically lies on her back on the ultrasound table.
- Partially Reclined: A slight elevation of the head and upper body can be more comfortable for some women, especially if they feel lightheaded when lying flat.
- Bladder State: For a transabdominal ultrasound, a partially full bladder can be helpful as it pushes the intestines away and provides a clearer view of the uterus. However, it's not always necessary at this early stage.

Probe Positioning & Scanning
- Probe Selection & Frequency: Curvilinear 3-5 MHz
- Apply Gel: Apply a generous amount of ultrasound gel to the lower abdomen.
- Initial Probe Placement: Choose the widest FOV (Field Of View) setting. - Adjust the depth and focus position. Place the probe in the midline, just above the pubic bone, with the probe marker pointing towards the patient's head.
- Obtaining Initial Image: Slowly sweep the probe upward until the uterus is visualized. The gestational sac, if present, is usually seen in the uterus.
- Locating Gestational Sac: Look for a round or oval anechoic (dark) area within the uterus, which is the gestational sac. Narrow the FOV and use zoom to focus on the gestational sac.

Mean Sac Diameter
- Measuring Gestational Sac: Once the gestational sac is located, measure it in three dimensions - length, width, and height. The average of these three measurements gives the mean sac diameter (MSD).
MSD = (Length + Width + Height) / 3

Example:
Length: 20 mm
Width: 18 mm
Height: 22 mm
MSD = (20 + 18 + 22)/3 = 20mm

Yolk Sac Measurement
- Measure the Diameter: Carefully place the calipers at the inner edges of the yolk sac, measuring the largest diameter.
- Multiple Measurements: It’s advisable to take at least two measurements and use the average for the most accurate size.

Measuring Crown-Rump Length
- Visualize the Embryo: Within the gestational sac, locate the embryo. It appears as a small structure adjacent to the yolk sac.
- Optimize Image: Adjust the probe to obtain a clear, sagittal view of the entire length of the embryo.
- Activate Measurement Tool: Engage the caliper function on your ultrasound machine.
- Place Calipers for Measurement: Position one caliper at the crown (head end) and the other at the rump (bottom end) of the embryo. The measurement should be taken in a straight line, not following the curvature of the embryo.
- Record the Measurement: Document the CRL measurement. Save images showing the embryo and the measurements. Use the CRL measurement to estimate the gestational age.

Fetal Heart Rate:
Locate the Fetal Heartbeat: After identifying the gestational sac and the fetal pole, look for the flickering motion of the fetal heart. This is often seen as a small, rhythmic movement within the embryo.
Optimize the Image: Adjust the position of the probe to obtain the clearest possible image of the fetal pole and heart. The heart should be in the center of the image. Use the ultrasound machine controls to optimize image clarity, adjusting depth, gain, and focus as needed.
Look for a button labeled “M-mode” or an option on the touchscreen if your machine has one. It might also be found under a 'Mode' menu. Press the “M-mode” button to switch from B-mode to M-mode. After switching to M-mode, a line (cursor) will appear on the screen. This line needs to be positioned across the fetal heart. Use the trackball, joystick, or touchscreen (depending on the machine) to move the cursor so that it bisects the fetal heart. The ideal position is through the area where the cardiac motion is most apparent.
Capture the M-Mode Trace: Once the cursor is correctly positioned, either press the “Freeze” button to capture the M-mode trace. This button freezes the image on the screen and shows the M-mode waveform.