In the past, a first trimester ultrasound has not been routinely performed. Pregnancy resource centers are reversing this trend by converting to medical clinics in order to offer first trimester ultrasounds to their patients. These centers check to confirm a viable intrauterine pregnancy (IUP) and allow patients to see their developing babies.

  
     
 
 


Taken at the mid-line of the uterus and in the longitudinal plane, show the proper landmarks in the image, including the maternal bladder, vaginal canal, cervix, uterus, gestational sac and posterior cul-de-sac. Be sure to annotate MLL for mid-line longitudinal or SAG for sagittal.

Next, scan completely out of the uterus to the right adnexa - then to the left adnexa.

  
 
     
 
 


Next, the probe is turned 90 degrees counter-clockwise toward the scanner in order to image in a transverse plane. Scan inferiorly to visualize the maternal vaginal canal, then the cervix, then scan superiorly through the uterus and the maternal bladder.

The second image is taken at the widest portion of the uterus and ideally, reveals the gestational sac.

  
 
     
 
 


When obtaining an accurate crown-rump length, be sure to visualize the longest axis of the baby. Adjust the depth in order to maximize the region of interest. Adjust the TGC’s and overall gain as necessary. Freeze the image. Zoom in on the region of interest. Select the measurement package, then choose the CRL option and use the calipers to measure the baby from the top of the head (crown) to the baby’s rump.

 
 
     
 
 


It is important to measure the CRL twice in order to show consistency. For the fourth image, repeat the steps in order to obtain the longest axis of the baby and measure the crown-rump length again. If the second measurement is consistent with the first (within a day or two) then the dating is considered accurate.

 
 
     
 
 


Record the fetal heart rate. Zoom in on the baby’s heart. Choose the mid-line key. Press the M-mode key for the motion of an area of the baby’s heart to be sampled. The monitor will reveal a duplex image. When a distinct waveform is evident, freeze the image, place calipers from the beginning of one beat to the beginning of the next beat to measure the beats per minute.

Make sure you print a report page, which records the measurements and patient data.