Study selection
The database search yielded 3336 citations: PubMed (n=636), Embase (n=1989), Cochrane Library (n= 621), clinicaltrials.gov (n=90). In total, 667 were identical duplicates, and excluded. After abstract assessment, 62 articles were extracted for full-text review. Ten articles dropped out because they included normal pregnancies without any risk factors, nor signs or symptoms that indicated placental insufficiency.. One study was excluded because of wrong outcomes and another was excluded due to lack of control group . Fourteen articles were excluded because of publication type or study design. Studies involving animals or human placenta were excluded, only clinical studies were included. Due to a lack of standardization in studies investigating biomolecular markers, those studies or results were excluded as well. The selection process is illustrated in Figure 1. Ultimately, ten studies were included in the analysis, with a total of 1391 pregnant women. Of them, 703 (50.5%) were treated with pravastatin and 688 (49.5%) were not treated with statins. All ten studies described high treatment adherence.