The uterus is formed from the paired mullerian ducts during embryogenesis. Uterine anomalies result from their defective migration, fusion, or absorption during embryonic life. The incidence of anomalies is difficult to estimate because many congenital anomalies do not result in clinical manifestations (Rock and Jones, 1977). Patients with symptomatic mullerian anomalies usually have signs of menstrual outflow obstruction or reproductive dysfunction. Diagnostic methods for determining the exact nature of a mullerian anomaly have evolved from bimanual examination, postpartum manual exploration, and D & C, to the more sophisticated techniques of hysterography, laparoscopy, hysteroscopy, ultrasonography, and MRI. Increased capacity of the latter techniques to yield complete information will undoubtedly be reflected in a higher reported incidence of the more subtle anomalies.
Retrospective studies reveal that approximately 25% of women with congenital uterine anomalies encounter re- productive difficulties, although conception rates are not different than they are among women in control groups (Abramovici et al, 1983; Harger, 1983). Spontaneous abortions, premature births, and fetal malpresentations are common in women with congenital uterine anomalies.
Anomalies can be classified as problems with hypoplasia or agenesis (American Fertility Society [AFS] class I) or as fusion defects (AFS classes II-V). Class I anomalies, also referred to as mullerian anomalies, usually are diagnosed in women who seek treatment for primary amenorrhea or for an inability to have vaginal intercourse. These defects are thought to occur developmentally when the mullerian structures fail to join with the structures arising from the vaginal bulb. There is a wide spectrum of defects ranging from isolated vaginal agenesis to hypoplasia of the vagina, cervix, ileus, and tubes.
Clinically important points of these anomalies include:
- In patients with complete mullerian agenesis, the possibility of complete androgen insensitivity (testicular feminization syndrome) should be considered because these women have Y chromosomes and must have their gonads removed because there is a high risk for neoplasia.
- The patient with an absent vagina can have one that is adequate for intercourse created through the use of progressive dilators or surgery.