Fibroids, or leiomyomas, are noncancerous monoclonal tumors of the smooth muscle layer of the uterus. Fibroids occur more frequently in Black patients and their prevalence increases with age. The hormonally responsive nature of fibroids, frequently leading to growth with estrogen and progesterone exposure, makes them of particular concern during pregnancy.
Although most patients with fibroids do not have pregnancy complications directly attributable to their fibroids, prior studies have reported several associations, including painful degeneration, early pregnancy loss, preterm birth, placental abruption, malpresentation, and postpartum hemorrhage. Fibroids may predispose to uterine atony and hemorrhage by disrupting or impairing the synchronization and coordination of uterine contractions. Within the current body of literature, it remains less certain whether certain fibroid characteristics are associated with increased hemorrhage risk.
Prior studies evaluating the association between specific fibroid characteristics and postpartum hemorrhage have yielded inconsistent findings. In our study, we evaluated whether certain fibroid characteristics are associated with hemorrhage requiring blood transfusion. Specifically, our goal was to determine whether larger or more numerous fibroids increase the risk of transfusion.
Dr. Yasaman Yaghoubian
This was a retrospective cohort study spanning 2019-2022. A total of 4,421 patients were included in this study. Fibroid characteristics were collected, including size, number, and location. Fibroid size was classified as small (< 5 cm), medium (5-10 cm), and large (> 10 cm).
In terms of number of fibroids, there was no significant increase in transfusions when comparing one fibroid to multiple fibroids. When assessing fibroid size, however, we did observe a significant incremental increase in rate of transfusions with increasing fibroid size. In terms of fibroid location, patients with fibroids in the lower uterine segment or cervix were about 1.5 times more likely to have hemorrhage requiring transfusion, compared with those without a fibroid in that location.
This study allows practitioners to better risk-stratify patients from the practical perspective of postpartum hemorrhage requiring transfusions. In pregnant patients with fibroids, the specific fibroid characteristics can help us better anticipate clinically significant postpartum hemorrhage. In such patients, it is important to document specific fibroid characteristics, especially the largest fibroid diameter and fibroid location in the lower uterine segment or cervix. This emphasizes the importance of careful sonographic evaluation and consistent documentation of fibroids in pregnant patients.
Our study helps guide more informed counseling and risk stratification in this population, with increasing risk according to fibroid size and location. Patients with high-risk features, that is, medium or large fibroids and those with fibroids located in the lower uterine segment or cervix, should thus receive counseling about their increased risk of hemorrhage. As providers, we can help ameliorate this risk by optimizing hemoglobin levels of those at increased risk prior to delivery, and by ensuring availability of appropriate resources at the time of delivery.
Dr. Yaghoubian is a maternal-fetal medicine fellow at North Shore University Hospital/Long Island Jewish Medical Center in Manhasset, N.Y., and will be joining the faculty at the same institution. Email Dr. Yaghoubian at yyaghoubian@northwell.edu.