In the research cases not every child had a real (amniotic) strand. It could be that there has to be another explanation for the development of these anomalies. Diagnosis
The diagnosis of constriction ring syndrome can be confirmed with an ultrasonography. The clinical manifestations can be extremely variable. It could be a single or multiple manifestation. This can be confirmed at the end of the first trimester or at the beginning of the second trimester. But not every patient will be diagnosed at that moment, most will get this diagnosis at birth.Individual strands are small and hard to see on ultrasound, so bands are detected indirectly because of the constrictions and swelling upon limbs or digits. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus. Decreased fetal movement could be a sign of a serious problem which may include ABS. It is rare but possible for the membrane to become wrapped around the placenta or the neck of the baby in the womb causing strangulation and death. There is a strong relationship between ABS and clubfoot (also called "talipes"). 31.5% of clubfoot cases can be correlated with ABS, with 20% occurring bilaterally. Other abnormalities found with ABS include: clubhands, cleft lip, and/or cleft palate, and hemangioma.
Because of these other anomalies the names "Constriction Ring Syndrome", "Constriction Band Syndrome", and "Streeter Bands" are given to this defect/disease. This is sometimes attributed to vascular disruption shared between cleft palate and other forms of cleft defects occurring together with ABS; this co-occurrence suggests an "intrinsic" defect of the blood circulation.The second theory postulates the involvement of an intrauterine disruption during pregnancy followed by a cascade of events involving amniotic rupture. When spontaneous rupture of the amnion occurs early in the second trimester, the separation of amnion from chorion produces many small, thin strands that can become entangled within digits and toes. Later, as the fetus grows but the bands do not, the bands become constricting. This constriction reduces blood circulation, hence causes congenital abnormalities. In some cases a complete "natural" amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth. The names "Amniotic Band Syndrome" (ABS), "Amniotic Disruption Complex", and "Amniochorionic Mesoblastic Fibrous Strings" are based on this theory. The third theory postulates the involvement of intrauterine trauma. Intrauterine trauma could be something like amniocentesis, or something like a fetal surgery. An intrauterine trauma could result in hemorrhage leading to acrosyndactyly. One study also showed the presence of bands as confirmed by sonography after fetal surgery.Because of these different theories, there are many names for this syndrome. For a long time people believed the second theory about the amniotic rupture and strands.