Maternal trauma due to motor vehicle crashes and pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVES: To systematically review and quantify the effect of motor vehicle crashes (MVCs) in pregnancy on maternal and offspring outcomes. DESIGN: Systematic review and meta-analysis of observational data searched from inception until 1 July 2018. Searching was from June to August 2018 in Medline, Embase, Web of Science, Scopus, Latin-American and Caribbean System on Health Sciences Information, Scientific Electronic Library Online, TRANSPORT, International Road Research Documentation, European Conference of Ministers of Transportation Databases, Cochrane Database of Systematic Reviews and Cochrane Central Register. PARTICIPANTS: Studies were selected if they focused on the effects of exposure MVC during pregnancy versus non-exposure, with follow-up to verify outcomes in various settings, including secondary care, collision and emergency, and inpatient care. DATA SYNTHESIS: For incidence data, we calculated a pooled estimate per 1000 women. For comparison of outcomes between women involved and those not involved in MVC, we calculated ORs with 95% CIs. Where possible, we statistically pooled the data using the random-effects model. The quality of studies used in the comparative analysis was assessed with Newcastle–Ottawa Scale. RESULTS: We included 19 studies (3 222 066 women) of which the majority was carried out in high-income countries (18/19). In population-level studies of women involved in MVC, maternal death occurred in 3.6 per 1000 (95% CI 0.25–10.42; 3 studies, 12 000 women; Tau=1.77), and fetal death or stillbirth in 6.6 per 1000 (95% CI 3.81–10.12; 8 studies, 47 992 women; I(2)=92.6%). Pooled incidence of complications per 1000 women involved in MVC was labour induction (276.43), preterm delivery (191.90) and caesarean section (166.65). Compared with women not involved in MVC, those involved had increased odds of placental abruption (OR 1.43, 95% CI 1.27–1.63; 3 studies, 1 500 825 women) and maternal death (OR 202.27; 95% CI 110.60–369.95; 1 study, 1 094 559 women). CONCLUSION: Pregnant women involved in MVC were at higher risk of maternal death and complications than those not involved. PROSPERO REGISTRATION NUMBER: CRD42018100788.