Primary amenorrhoea: a retrospective study at Siriraj Hospital.

To determine the incidence of etiologic factors responsible for primary amenorrhoea in Siriraj Hospital on the basis of clinical examination and laboratory investigations. A retrospective study was performed from the records of patients who attended the Reproductive endocrine Clinic at Siriraj Hospital from 1 September 1992 to 31 August 1995. During the 3 years of the study period, there were 110 cases of primary amenorrhoea. One hundred and one cases were analyzed: nine cases were excluded because the patients lost follow-up before the final diagnosis could be concluded. The two most common etiologic factors were mullerian agenesis (39.65%) and gonadal dysgenesis (32.69%). Mean age of the patients when they first consulted the physicians was 22.45 +/- 6.06 years. Karyotyping was done on 28 of 32 cases of gonadal dysgenesis; 46,XX karyotype was found in 50 per cent and 45,XO in 14.29 per cent of analyzed cases. Clinical examination gave wrong diagnosis of absent uterus in 4 cases who were in the hypoestrogenic stage with hypoplastic uterus; ultrasonography and laparoscopy gave the wrong diagnosis in 1 case each in our report. These patients successfully menstruated after hormonal replacement therapy. The incidence of etiologic causes and cytogenetic study of primary amenorrhoea in our study is different from earlier reports. Racial and environmental differences may play a role in these differences. The facilities of diagnostic tools may also play a part. However, both clinical examination and many laboratory investigations have to be completed before final diagnosis of etiologic causes of primary amenorrhoea are elucidated. Diagnosis based on inadequate data can be misleading.