The effect of parnaparin sodium on in vitro fertilization outcome: A prospective randomized controlled trial

Introduction In-vitro and in-vivo models suggest the influence of low-molecular weight heparin on conception in infertile women undergoing in vitro fertilization procedures (IVF). In this randomized controlled trial we assessed whether a low-molecular weight heparin (parnaparin) could affect IVF outcomes. Materials and methods 271 cycles were analyzed in 247 women having a first or subsequent IVF cycle at Fertility Center of Humanitas Research Hospital. Patients, without severe thrombophilia and hormonal or active untreated autoimmune disorders, were randomly allocated (1:1) to receive for the whole cycle parnaparin, or routine hormonal therapy only. The primary endpoint was the clinical pregnancy rate and the secondary endpoints included implantation rate and live birth rate. Results The clinical pregnancy and the live birth rate were similar in treated and controls (21.5% vs. 26.7%, p = 0.389; 18.5% vs. 20.6%, p = 0.757). The abortion rate was 10.3% vs 22.9%, p = 0.319, respectively. The subgroups analysis, ≤ 35, 36–38, 39–40 years, showed the following: comparable clinical pregnancy rate (22.5% vs 38.8%, p = 0.124; 21.8% vs 17.3%, p = 0.631; 19.4% vs 23.3%, p = 0.762 respectively) and live birth rate (16.3% vs 32.7%, p = 0.099; 20.0% vs 13.5%, p = 0.443; 19.4% vs 13.3%, p = 0.731 respectively) in treated vs controls. Sensitivity analyses on women with ≥ 3 previous attempts and first enrolment only, and subgroup analyses according to trial conclusion conditioning a small sample size with low statistical power. Conclusions Our study excludes positive effect of parnaparin, once a day for the whole cycle, on clinical pregnancy rate in infertile women undergoing in vitro fertilization techniques.