Acute pelvic pain is a common reason for women to seek urgent gynecologic evaluation. Although the classic clinical presentation is dysmenorrhea with premenstrual intensification, dyspareunia, and chronic pelvic pain, some patients, who may or may not know they have the condition, experience acute pelvic pain. Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication of superovulation induction therapy with a varied spectrum of clinical and laboratory manifestations. Crampy pelvic pain due to hormonal changes, rapid growth of the uterus, and increased blood flow is a common sign of early pregnancy. If a patient fails a single course of methotrexate or has pelvic pain that is increasing, ultrasound can be helpful. If a patient continues to have pain after a presumed miscarriage, even if products of conception were confirmed cytologically, a heterotopic pregnancy should be a considered.

Haemorrhagic corpus luteum cysts are common causes of acute pelvic pain in women of fertile age. At ultrasound examination, corpus luteum cysts are characterised by spiderweb-like contents but they may also contain bizarre-looking blood clots. This explains why corpus luteum cysts may sometimes be confused with malignancy. Endometriomas may cause pelvic pain but they are also quite common incidental ultrasound findings. A serious condition that may be more or less painful is torsion of the adnexa. Torsion occurs in adnexa containing a lesion, such as ovarian cyst or hydrosalpinx, but it may also occur in normal adnexa, especially in prepubertal girls. Uterine fibroids and adenomyosis may sometimes cause pelvic pain. Gynaecologists should be able to recognise the ultrasound image of non-gynaecological conditions that may cause pelvic pain. Ultrasound images of these conditions may be encountered when an ultrasound examination is performed because of suspicion of gynaecological disease.