Fetal akinesia may occur as a result of deformation caused by external
factors. Potter's syndrome due to renal agenesis causes profound
oligohydramnios and akinesia due to the decreased fetal movement in the
restricted environment. This may occur from any cause of oligohydramnios
including premature rupture of membranes.
Distinguishing features between the oligohydramnios sequence and fetal
akinesia deformation sequence include:
- Positional abnormalities
occur in both, however in FADS these are usually symmetrical whereas in
extrinsically derived fetal akinesia they are often asymmetrical.
- In the oligohydramnios
sequence, the immobilization occurs after muscle development is complete,
so bone mass and muscle size is usually normal. In FADS, bone mass is
usually decreased.
- Micrognathia may be present
in both, however, there is better bone growth of the face and mandible in
the oligohydramnios sequence.
- Sherer DM, Jaffee R, Metlay
LA et.al. Absent fetal swallowing: A possible role in the pathogenesis of
micrognathia. Am J Obstet Gynecol 1994;170:348.
- Palacois J, Rodriguez J.
Extrinsic fetal akinesia and skeletal development: A study in
oligohydramnios sequence. Teratology 1990;42:1.