Fetal growth and spontaneous preterm birth in high‐altitude pregnancy: A systematic review, meta‐analysis, and meta‐regression

Objective To understand the relationship between birth weight and altitude to improve health outcomes in high‐altitude populations, to systematically assess the impact of altitude on the likelihood of low birth weight (LBW), small for gestational age (SGA), and spontaneous preterm birth (sPTB), and to estimate the magnitude of reduced birth weight associated with altitude. Methods PubMed, OvidEMBASE, Cochrane Library, Medline, Web of Science, and clinicaltrials.gov were searched (from inception to November 11, 2020). Observational, cohort, or case‐control studies were included if they reported a high altitude (>2500 m) and appropriate control population. Results Of 2524 studies identified, 59 were included (n = 1 604 770 pregnancies). Data were ed according to PRISMA guidelines, and were pooled using random‐effects models. There are greater odds of LBW (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.33–1.62, P