Sonographers should be aware of the prevalence, etiology, prenatal sonographic features, management and prognosis for both common and rare fetal abnormalities.The 18-23 weeks scan aims to assess the fetal anatomy and growth, the amount of amniotic fluid and the position of the placenta. Better visualization of the fetal anatomy is achieved at 21-23 weeks, rather than at 18-19 weeks.
There is good evidence that in this scan the cervical length (for assessment of risk for preterm birth) and uterine artery pulsatility index (for assessment of risk for preeclampsia and fetal growth restriction) should also be measured.
Requirements for certification
The requirements for obtaining the FMF certificate of competence in the 18-23 weeks scan are:
- Attendance of a World Congress in Fetal Medicine and a FMF Advanced Course in Fetal Medicine.
- Submission of a log-book of a series of images from one normal fetus.
- Demonstration to a FMF approved examiner of competence in carrying out a 18-23 weeks scan and good knowledge of the diagnosis and management of a wide spectrum of fetal abnormalities.
You will find useful to read the book The 18-23 weeks scan, which you can download free of charge here.
Logbook of images
The images should demonstrate the following views:
- Transverse view of the head at the level of the septum cavum pellucidum for measurement of biparietal diameter, head circumference, hemisphere and cerebral ventricles
- Suboccipital-bregmatic view of the head for measurement of cerebellum and cisterna magna
- Transverse views of the face through the orbits and the upper lip and maxilla
- Sagital view of the face (profile) demonstrating the nasal bone
- Four-chamber view of the heart
- Views demonstrating the outflow tracks of the heart
- Transverse view of the abdomen at the level of the stomach and umbilical vein for measurement of the abdominal circumference
- Transverse views of the abdomen to demonstrate the kidneys
- Transverse or longitudinal view to demonstrate the umbilicus
- Transverse or longitudinal view to demonstrate the bladder
- Longitudinal view to demonstrate measurement of the femur
- Longitudinal view to demonstrate the leg and foot
- View of the open hand
- One or two longitudinal views demonstrating the whole spine
- Transverse view of the sacral spine
- Longitudinal view demonstrating the relation between the lower end of the placenta and the cervix
Please send your completed logbook to:
The 18-23 weeks scan
The Fetal Medicine Foundation
137 Harley Street
London, W1G 6BG