Imperforate hymen is the most frequent cause of haematocolpos, although it is a rare malformation (1:2000). We present two cases of young girls with cyclic abdominal pain and urinary symptoms. At gynaecological examination, they all presented imperforate hymen and ultrasound revealed significant vaginal distension. X-shaped hymenectomy was performed in all patients. The later the diagnosis of imperforate hymen, the higher the risk of complications like haematometra, haematosalpinx, haemoperitoneum and infections such as tubo-ovarian abscesses, peritonitis and endometriosis (retrograde menstruation theory).

This case report suggests that the etonogestrel implant is effective for even longer than the most recent studies have shown.