Cases with three or more consecutive spontaneous abortions before the 20th week of gestation are termed as recurrent pregnancy loss (RPL). Problems in implantation of the foetus and any retarded growth of the foetus in the uterus can be correlated to RPL. Possible causes of RPL would include the genetic variations in the regulatory enzymes of the crucial metabolic pathways, clotting factors, hormones and hormone receptors. This defect of the mitochondrial respiratory chain is recognized as a major cause of human disease. We investigated 73 women with RPL and 100 healthy normal controls. By using the direct sequencing method, the amplified products including the mtDNA complex I genes were analyzed. Overall, seven variations in mitochondrial complex I genes were found (T4216C, A5153G, C10142T, C12062T, A12662G, G14179A and T14263C) using direct sequencing technique. The RPL group had significantly higher proportions of the different variants than those observed of the control group. In conclusion, more research is essentially needed to understand the effect and role of the mitochondrial variations in the progress of RPL, which may vary among individuals and different ethnic groups.
Keywords: Mitochondrial DNA; mitochondrial variations; recurrent pregnancy loss.