Unexplained recurrent implantation failures: Predictive factors of pregnancy and therapeutic management from a French multicentre study.

Introduction: Recurrent implantation failure is defined as the absence of pregnancy after at least three transfers of good-quality embryos after in vitro fecundation/intracytoplasic sperm injection.
Aim: The aim of this study was to describe a multicentre cohort of women with unexplained RIF, to analyse the factors associated with clinical pregnancy and to evaluate the immunomodulatory therapies efficacy.
Methods: Women were consecutively recruited from university departments with unexplained RIF.
Results: Sixty-four women were enrolled with mean age 36 ± 3 years. The rates of clinical pregnancy in 64 women were compared in untreated and treated cycles and according to therapies used during the last prospectively followed embryo transfer. A clinical pregnancy after the transfer was noted in 56 % pregnancies on intralipids and in 50 % on prednisone, versus 5 % in untreated ones (p < 0.001). The 340 embryo transfers of these 64 women resulted in 68 clinical pregnancies and 18 live births. Clinical pregnancies were significantly more frequent in treated versus untreated embryo transfers (44 % vs 9 %; p < 0.001) with odds ratio at 8.13 (95 % CI 4.49-14.72, p < 0.0001). Cumulative pregnancy rates were higher for steroid-treated transfers than for untreated transfers when considering overall transfers before and after using steroids and also only those under steroids. Cumulative pregnancy rates were not different from steroid- and intralipid-treated embryo transfers CONCLUSIONS: In this multicentre study of women with unexplained RIF, use of immunomodulatory treatments before embryo transfer resulted in higher clinical pregnancy. Randomised, well-designed studies in well-defined population of RIF women are necessary to confirm our preliminary data.
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