Mindy S. Christianson, MD
A second study also evaluated the growth uterine fibroids during a different time during a woman’s lifespan - pregnancy. While it’s commonly thought that fibroids grow during pregnancy, a prospective cross-sectional study in the International Journal of Gynecology & Obstetrics (Tian et al) evaluated 394 women with uterine fibroids and found that growth depended on gestational age. In this group, ultrasound examinations were conducted to measure the size of uterine fibroids during weeks 6–7, 11–14, 22–24 and 28–34 of pregnancy and before delivery. The study team found that uterine fibroid size commonly increased before 22–24 weeks of pregnancy with the fastest growth occurring before 11–14 weeks gestation. Later in pregnancy, from 22–24 weeks to the date of delivery, uterine fibroid size remained unchanged.
Lin et al published a large-scale nationwide cohort study in PLoS One that evaluated whether women with uterine fibroids were at increased risk of developing endometriosis. Overall, 31,239 women with uterine fibroids were matched to 124, 956 control participants and followed for 14 years. Compared to controls, patients with uterine fibroids were at a higher risk of developing endometriosis (adjusted hazard ratio [aHR] 6.44, P < 0.05). Other conditions associated with a higher risk of endometriosis included history of tubo-ovarian infection (aHR 2.86, P = 0.01), endometritis (aHR 1.14, P < 0.001), infertility (aHR 1.26, P < 0.001) and allergic diseases (aHR, 1.11, P < .001). Similarly, having both uterine fibroids and infertility significantly increased the risk of endometriosis (aHR 6.95; P < 0.001).