Luteal Phase Empirical Low Molecular Weight Heparin (LMWH) Administration in Patients with Unexplained Repeated Implantation Failure (RIF)

Objective: We investigated whether LMWH treatment is effective in unexplained RIF patients.

Material and method : Total 84 women with 3≥ failed ART cycles were included in these retrospective study.We underwent controlled ovarian hyperstimulation with flexible GnRH antagonist protocol. Study population included 21 RIF patient with administration of LMWH ( 1mg/kg/day) from the day of embryo transfer up to the 8^th gestational week in pregnancy and 63 RIF patients with no treatment. Pregnancy rate (PR) and clinical pregnancy rate (CPR) were analyzed at the 12days after ovum retrieval and 12 weeks gestation.

Result: There were no statistical significance in patients characteristics and ART outcomes in LMWH and no treatment groups (Age: 35.1±2.5 vs. 35.3±3.1, Cycle No: 4.8±2.5 vs. 4.9±2.1, No of retrieved oocyte: 10.6±8.4 vs. 11.8±5.4, No of ET:2.2±1.0 vs. 2.5±1.2). There were 8 pregnancy (8/21 (38.1%)) in LMWH treatment group, and 18 pregnancy (18/63(25.4%)) in no treatment group(p=0.27). CPR were 23.8 (5/21)% in LMWH treatment group and 17.5(11/63)% in no treatment group(p=0.5).

Conclusion: Despite lack of statistical significance, the PR and CPR tend to be increased in LMWH treatment group compared to no treatment group. Further research on the use of LMWH in women with unexplained RIF patients was needed. However, in the absence of proven treatment for RIF treatment, LMWH treatment may be helpful option in improving the pregnancy and clinical pregnancy rate. Failure to demonstrate statistical significance of these study may be due to limited sample size.