The impact of fibroid characteristics on pregnancy outcome

The objective of the study was to assess the influence of different characteristics of fibroids on pregnancy outcome.

We identified women with fibroids 4 cm or greater in size on ultrasonography at the dating scan between January 2002 and December 2012. The size (4-7 cm, 7-10 cm, >10 cm), 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, birthweight, mode of delivery, estimated blood loss, postpartum hemorrhage, and admission for fibroid-related pain).

A total of 121 patients with 179 pregnancies were identified. Preterm delivery was more likely in those with multiple fibroids compared with single fibroids (18% vs 6%; P = .05). The location of the fibroid had an important effect on the mode of delivery with a higher cesarean section rate for fibroids in the lower part of uterus than in the body of the uterus (86% vs 40%; P = .01), a higher rate of postpartum hemorrhage (22% vs 11%; P = .03), and greater estimated blood loss (830 mL [SD, 551] vs 573 mL [SD, 383]; P = .03). Increasing size of fibroid was associated with greater rates of hemorrhage (11% vs 13% vs 36%; P = .04), increased estimated blood loss (567 mL [SD, 365] vs 643 mL [SD, 365] vs 961 mL [SD, 764]; P = .01), and higher rates of admissions for fibroid-related pain (5% vs 23% vs 21%; P = .01).

Different fibroid characteristics affect pregnancy outcome in varying ways. This information can be used to aid counseling women antenatally and in risk-stratifying patients.