OBJECTIVE: Cryopreservation of oocytes and embryos by vitrification is currently the method of choice employed by most facilities that practice assisted reproductive technology (ART) and there are several studies reporting impressive outcomes. This specialized technique, however, is operator-dependent, so results do vary amongst embryologists and clinics. In Nigeria, vitrification is rapidly gaining widespread popularity as many hospitals are gradually incorporating this technique into their ART practice. This study aims to show the success of an IVF clinic in a developing country at implementing conventional vitrification and warming protocols with survival rates of vitrified-warmed blastocysts reassessed
DESIGN: A retrospective study of 171 FET cycles with a total of 485 embryos vitrified and subsequently warmed within a period of two years and three months (October 2015-December 2017).
MATERIALS AND METHODS: This study was conducted at Medical Art Center (MART), a private fertility clinic in Lagos, Nigeria. Participants included infertile couples going through frozen embryo transfers after prior failed in-vitro fertilization (IVF) cycles and in some cases, patients susceptible to OHSS with previous freeze all cycles. Vitrification and subsequent warming was performed with Medicult vitrification and warming media (Origio/Medicult, Målov, Denmark) using the McGill cryoleaf protocol as described by the manufacturer (Medicult, Denmark).
RESULTS: A total of 146 vitrification cycles were carried out for patients who went through frozen embryo transfers within the study period (Oct 2015-Dec 2017). In 171 FET cycles, 485 vitrified blastocysts were warmed with 358 blastocysts surviving the procedure. The freeze-thaw survival rate was 73.8%, and the average survival rate per freeze-thaw method was 80.5%. The total number of embryos transferred was 343 (average of 2.1 embryos per patient). 166 embryo transfers were performed. 2 FET cycles required re-vitrification of embryos without a transfer taking place, and only 3 patients had no surviving embryos.
CONCLUSIONS: Our study supports existing reports from publications highlighting excellent outcomes with vitrification. We were able to achieve high embryo survival rates; therefore, we have adopted Vitrification as the only method of choice for cryopreserving embryos. It may be recommended to other IVF clinics looking to improve their freeze-thaw survival rates.