Uterine fibroids and preterm birth risk: A systematic review and meta-analysis.

AIM: This study explored the association between the presence of uterine fibroids (UF), as determined by ultrasound, and preterm birth (PB) risk. METHODS: Medline, Embase, Cochrane, Scopus and Web of Science databases. Studies reporting women with and without UF demonstrated by an ultrasound exam. The primary outcome was the risk of PB < 37 weeks of gestation in pregnancies with UF diagnosed by an obstetric ultrasound exam. Effects for dichotomous and continuous outcomes are, respectively, reported as risk ratios (RR) or mean differences and their 95% confidence intervals (CI). RESULTS: Eighteen studies were included comprising 276 172 pregnancies to whom obstetric ultrasound assessment was performed for the presence/absence of UF. Women with UF were older (mean difference = 2.40 years, 95% CI 0.94-3.85) and were at higher risk of PB before 37 (RR = 1.43, 95% CI 1.27-1.60), 34 (RR = 1.79, 95% CI 1.32-2.42), 32 (RR = 1.94, 95% CI 1.33-2.85) and 28 (RR = 2.17, 95% CI 1.48-3.17) weeks as compared to those without UF (P < 0.01). In addition, women with UF were at higher risk of threatened preterm labor, preterm premature rupture of membranes, fetal malpresentation, placental abruption, lower gestational age and birthweight at delivery and a higher cesarean delivery rate. CONCLUSION: Pregnant women with UF are at increased risk of PB and other adverse obstetric outcomes.