Employ the protocol used for a single gestation pregnancy, but measure each baby separately. Select the multiple gestation package in order to record the findings for each baby in the report package.

  
     
 
 


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, uterus, gestational sacs 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 at a ninety-degree angle counter-clockwise 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 both gestational sacs and babies.

  
 
     
 
 


The need to identify landmarks is essential in a twin pregnancy in order not to confuse one baby with the other.

For accuracy in dating gestational age, a crown-rump length measurement is required. It is important to identify each fetus in relation to the maternal cervix as the baby closest to the cervix is considered 'Baby A'. Once the relationships have been established the first CRL can be taken.

 
 
     
 
 


When obtaining an accurate crown-rump length, visualize the longest axis of the baby, then adjust the depth in order to maximize the region of interest. Adjust the TGC’s and overall gain as necessary. Freeze the image, then zoom up on the region of interest - allowing for the best resolution. 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.

 
 
     
 
 


To record the fetal heart rate, zoom in on the baby’s heart. Choose the mid-line key. Then, press the M-mode key which will allow for an area of the baby’s heart to be sampled. The monitor will display 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.

  
 
     
   
     
 
 


'Baby B' is farthest from the cervix. Visualize the longest axis of the baby, then adjust the depth in order to maximize the region of interest. Adjust the TGC’s and overall gain as necessary. Freeze the image, then zoom up on the region of interest - allowing for the best resolution. 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.

 
 
     
 
 


The need to identify landmarks is essential in a twin pregnancy in order not to confuse one baby with the other.

For accuracy in dating the gestational age, a second crown-rump length measurement is required. It is important to identify each fetus in relation to the maternal cervix and to note whether one sac is present or two.

 
 
     
 
 


To record the fetal heart rate, zoom in on the baby’s heart. Choose the mid-line key. Then, press the M-mode key which will allow for 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. Print report.

  
 
 
  There are two types of twins, identical and fraternal.  

 

Identical twins come from one egg (monozygotic) and have identical genes.

 

 

Identical twins are the result of one egg joining with one sperm to form a zygote. The zygote then completely splits.

 

 

Fraternal twins come from two eggs (dizygotic) and two sperm, they have the same genetic similarities and differences as singleton brothers and sisters share.

 

 

Half of all fraternal twins are male-female, one quarter are male-male and one quarter are female-female.

  

 

Identical twins are the result of one egg joining with one sperm to form a zygote. The zygote then completely splits.

 

 

If the zygote splits early, one to three days after fertilization, each embryo will have a separate chorion and amnion.

 

 

The chorion produces the chorionic villi, which combined with tissue, called the decidua basalis, forms the placenta.

 

 

The later the zygote splits after fertilization, 4-8 days the greater the likelihood they will share one chorion.

 

 

If the zygote splits after 6 days the chorion and amnion might be shared.

  

  If the zygote splits after 14 days they may be conjoined.