Second trimester ultrasound scan
Updates to Synonym Attributes
Updates to Article Attributes
The second trimester scan is a routine ultrasound examination (in many countries) that is primarily used to assess fetal anatomy and detect the presence of any fetal anomalies.
The second trimester extends from 13 weeks and 0 days to 27 weeks and 6 days of gestation although the majority of these studies are performed between 18 and 23 weeks.
Alternate names for the study include second trimester anatomy scan, fetal anomaly scan or TIFFA (targeted imaging for fetal anomalies).
Biometry
The following measurements are routinely obtained to calculate fetal size and estimated delivery date (EDD).
Second trimester calculation of EDD based on these parameters has a generally accepted error margin of +/- 7 days.
Morphologic assessment
The following structures should be visualised at a routine second trimester morphology ultrasound.
Fetal head
- fetal skull: integrity and shape
- fetal brain:
- ventricles and choroid plexus
- cavum septum pellucidum
- posterior fossa, including measurements of trans-cerebellar diameter and cisterna magna
. - nuchal thickness
Fetal face
- profile and nasal bone
- orbits and lenses
- upper lip and palate
- mandible
Fetal heart and chest
- fetal heart rate and rhythm
- cardiac situs
- four chamber view
- outflow tract views
- aortic and ductal arches
- diaphragm and lungs
Fetal abdomen
- liver
- stomach (including situs)
- kidneys and renal arteries
- abdominal wall
- umbilical cord insertion
- bladder and umbilical arteries
-
pre sacralpresacral space - fetal gender
Fetal musculoskeletal system
- spine
- transverse, longitudinal +/- coronal views and skin line
- upper limb
- humera, including humeral length (HL)
- radius
-ulna - both/ulna: both sides - fingers and thumbs, including hand opening
- lower limb
- both femora, including femoral length (FL) as part of biometric assessment
- both
tib-fibtibia/fibula: saggital views to demonstrate orientation of the ankles to screen for talipes. - both feet
Ancilliary findings
- fetal lie
- cervical length
-
placenta
- site
- distance to cervix
- liquor volume
- umbilical cord including the number of cord vessels and evaluation of knots
-<li>posterior fossa, including measurements of <a href="/articles/transverse-cerebellar-diameter">trans-cerebellar diameter </a>and <a href="/articles/cisterna-magna">cisterna magna</a>.</li>- +<li>posterior fossa, including measurements of <a href="/articles/transverse-cerebellar-diameter">trans-cerebellar diameter </a>and <a href="/articles/cisterna-magna">cisterna magna</a>
- +</li>
-<li>pre sacral space</li>- +<li>presacral space</li>
-<li>humera, including humeral length (HL)</li>-<li>radius-ulna - both sides</li>- +<li>humera, including <a title="humeral length" href="/articles/humeral-length">humeral length</a> (HL)</li>
- +<li>radius/ulna: both sides</li>
-<li>both tib-fib: saggital views to demonstrate orientation of the ankles to screen for <a href="/articles/congenital-talipes-equinovarus">talipes</a>.</li>- +<li>both tibia/fibula: saggital views to demonstrate orientation of the ankles to screen for <a href="/articles/congenital-talipes-equinovarus">talipes</a>.</li>
-<a title="placenta" href="/articles/placenta">placenta</a><ul>- +<a href="/articles/placenta">placenta</a><ul>
References changed:
- 4. Bethune M, Alibrahim E, Davies B, Yong E. A pictorial guide for the second trimester ultrasound. (2013) Australasian journal of ultrasound in medicine. 16 (3): 98-113. <a href="https://doi.org/10.1002/j.2205-0140.2013.tb00106.x">doi:10.1002/j.2205-0140.2013.tb00106.x</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28191183">Pubmed</a> <span class="ref_v4"></span>
- 4. A pictorial guide for the second trimester ultrasound Bethune M et al, AJUM August 2013; 16 (3):98-113
Sections changed:
- Approach