Visual loss in pregnancy may be caused by a variety of reasons including pituitary adenomas. Prolactinomas (PRLs) are the commonest hormone-secreting tumours in pregnant women. As most PRLs present with menstrual abnormalities, infertility or galactorrhoea, they are most commonly diagnosed before pregnancy. We present the case of a 30 year-old primigravida who presented at 36+5 weeks gestation with headaches and left sided visual loss. Magnetic resonance imaging (MRI) of the pituitary gland confirmed a 10mm x 11mm left suprasellar mass. Results of her anterior pituitary function were unremarkable for her gestational age. Post-partum she underwent an endoscopic endonasal resection of the pituitary tumour. The histology was consistent with a prolactinoma (PRL). Literature review reveals only one possible case of a new diagnosis of a prolactinoma during pregnancy. It highlights the importance to consider a wide range of differential diagnoses when assessing visual loss in pregnancy.