Objective: To assess the influence of different characteristics of fibroids on pregnancy outcome.Study design: We identified women with fibroids ≥4 cm in size on ultrasonography at the dating scan between January 2002 and December 2012. The size (4-7cm, 7-10cm, >10cm), number (multiple/single), location (lower uterus/body of uterus) and type (intramural, combination of intramural/subserosal, subserosal) were ascertained. Medical records were reviewed to obtain pregnancy outcomes (preterm delivery, birth weight, mode of delivery, estimated blood loss, postpartum haemorrhage and admission for fibroid related pain).Results: 121 patients with 179 pregnancies were identified. Preterm delivery was more likely in those with multiple fibroids compared to single fibroids (18% v 6% p=0.05). The location of fibroid had an important effect on mode of delivery with a higher caesarean section rate for fibroids in the lower part of uterus than in the body of the uterus (86% v 40% p=0.01), a higher rate of postpartum haemorrhage (22% v 11%p=0.03) and greater estimated blood loss This information can be used to aid counselling women antenatally and in risk stratifying patients.