Imaging for acute pelvic pain in pregnancy.

Acute pelvic pain in pregnancy presents diagnostic and therapeutic challenges. Standard imaging techniques need to be adapted to reduce harm to the foetus from X-rays because of their teratogenic and carcinogenic potential. Ultrasound remains the primary imaging investigation of the pregnant abdomen. Magnetic resonance imaging (MRI) has been shown to be useful in the diagnosis of gynaecological and obstetric problems during pregnancy and in the setting of acute abdomen during pregnancy. MRI overcomes some of the limitations of ultrasound, mainly the size of the gravid uterus. MRI poses theoretical risks to the foetus and care must be taken to minimise these with the avoidance of contrast agents. Teaching Points • Ultrasound and MRI are the preferred investigations for acute pelvic pain during pregnancy. • Ultrasound remains the primary imaging investigation because of availability and portability. • MRI helps differentiate causes of acute pelvic pain when ultrasound is inconclusive.