Figure 3: Multivariate adjusted RRs and 95% CIs of the risk of PTB by domestic PA during pregnancy among 10 observational studies.

The pooled estimates (diamond data markers) were obtained using a random-effects model. The dots indicate the RRs for the risk of PTB comparing the highest with the lowest domestic PA level during pregnancy. The size of the shaded square is proportional to the percentage weight of each study. The horizontal lines represent 95% CIs. CI: confidence interval; RR: relative risk.