Our aim, in the present study, was, therefore, to evaluate whether treatment with LF prior to amniocentesis might influence the production of active MMP-9, active MMP-2, their specific inhibitors, TIMP-1 and TIMP-2, and PGE2 in the AF of pregnant women undergoing midtrimester genetic amniocentesis. The gene discussed is TIMP1; the disease is atrial fibrillation.