Circulating Transforming Growth Factor-β1 Levels in Preeclamptic Women: a Meta-analysis

Transforming growth factor (TGF)-β1, an angiogenic factor in the maternal circulation, has been suggested to be related to preeclampsia. However, the findings from previous studies were inconsistent. Thus, we conducted a meta-analysis to assess the difference in circulating TGF-β1 levels between women with preeclampsia and normal pregnancies. Twenty-four studies including 1748 women with PE and 1404 women with normal pregnancy were included in our study. The results showed that circulating TGF-β1 levels were not different before the time of active disease (standardized mean differences, - 0.46 [95% CI, - 0.16 to 0.15]; P = 0.000). At the time of active disease, women with preeclampsia (n = 1207) had higher circulating TGF-β1 levels than normotensive controls (n = 912; standardized mean differences, 0.94 [95% CI, 0.52 to 1.35]; P = 0.000). Circulating TGF-β1 levels were higher in both early-onset/severe and late-onset/mild types of preeclampsia. No publication biases were found. We conclude that preeclamptic women have higher circulating TGF-β1 than those with normal pregnancy at the time of preeclampsia diagnosis.