Higher risk of stillbirth found in women with fibroids

IUFD, or still birth, is rare and affects only six to seven out of every thousand births.

The study, conducted by researchers at Washington University in St. Louis, Mo., identified women who had fibroids detected during their routine second trimester ultrasound for anatomic survey at 16-22 weeks.

"Fibroids are very common," said Dr. Molly J. Stout, one of the study's authors. "We think they occur in 5% to 20% of all women, but most women are asymptomatic and don't even know they have them."

The study was a retrospective cohort study of 64,047 women. Data were extracted on maternal sociodemographics, medical history, and obstetric outcomes. Pregnancies with any fetal anomalies were excluded. Women with at least one fibroid detected at the time of fetal anatomic survey were compared to women without fibroids. The primary outcome was IUFD after 20 weeks gestation. Univariate and multiple logistic regression analyses were used to estimate the risk of IUFD in women with fibroids, and subgroup was conducted by presence or absence of fetal growth restriction (IUGR).

The study found that of 64,047 women, the incidence of fibroids was 3.2% (n=2,058). The incidence of IUFD was significantly higher in the fibroid group than in the no-fibroid group (1.6% v. 0.7%, aOR 1.8, 95%CI 1.3-2.7) even after adjusting for factors including black race, tobacco exposure, chronic hypertension, and pregestational diabetes. In subgroup analysis, the risk relationship between fibroids and IUFD only persisted within the IUGR subgroup.

"Our results showed that women with a combination of fibroids and fetal growth restriction were at two-and-a-half times the risk of having a stillbirth, though the absolute risk remained rare," said Dr. Alison G. Cahill, another of the study's authors. "This may lead to a future recommendation for serial growth scans to monitor fetal growth in women with fibroids."