Background Trichomoniasis commonly affects women of childbearing age and has been linked to several adverse birth outcomes.Objective To elucidate the association between trichomoniasis in pregnant women and adverse birth outcomes, including preterm delivery, prelabour rupture of membranes and low birthweight.Search strategy MEDLINE, EMBASE and ClinicalTrials.gov were systematically searched in December 2020 without time or language restrictions.Selection criteria Original research studies were included if they assessed at least one of the specified adverse birth outcomes in pregnant women with laboratory-diagnosed trichomoniasis.Data collection and analysis Estimates from included articles were either extracted or calculated and then pooled to produce a combined estimate of the association of trichomoniasis with each adverse birth outcome using the random effects model. Heterogeneity was assessed using the I 2 statistic and Cochran's Q test.Main results Literature search produced 1658 publications after removal of duplicates (n = 770), with five additional publications identified by hand search. After screening titles and abstracts for relevance, full text of 84 studies was reviewed and 19 met inclusion criteria for meta-analysis. Significant associations were found between trichomoniasis and preterm delivery (OR 1.27; 95% CI 1.08-1.50), prelabour rupture of membranes (OR 1.87; 95% CI 1.53-2.29) and low birthweight (OR 2.12; 95% CI 1.15-3.91).Conclusions Trichomoniasis in pregnant women is associated with preterm delivery, prelabour rupture of membranes and low birthweight. Rigorous studies are needed to determine the impact of universal trichomoniasis screening and treatment during pregnancy on reducing perinatal morbidity.