"class I: uterine agenesis/uterine hypoplasia"
"a: vaginal (uterus: normal/variety of abnormal forms)"
"b: cervical"
"c: fundal"
"d: tubal"
"e: combined"
"class II: unicornuate uterus/unicornis unicollis, ~15% (range 6-25%)"
"a: communicating contralateral rudimentary horn contains endometrium"
"b: non-communicating contralateral rudimentary horn contains endometrium"
"c: contralateral horn has no uterine cavity"
"d: no horn"
"class III: uterus didelphys, ~7.5% (range 5-11%)"
"class IV: bicornuate uterus: 2nd most common type ~25% (range 10-39%)"
"a: complete division, all the way down to the external os (bicornuate bicollis)"
"b: partial division, not extending to the internal os (bicornuate unicollis)"
"class V: septate uterus: commonest anomaly, ~45% (range 34-55%)"
"a: complete division, all the way down to the internal or external os"
"b: incomplete division, involving the uterine cavity but not the cervix"
"class VI: arcuate uterus, ~7%"
"class VII: in utero diethylstilboestrol (DES) exposure (T-shaped uterus)"
"Müllerian duct"