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 end-points 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.