Zygote Intrafallopian Transfer (ZIFT): A Viable Option for Women of Advanced Maternal Age

Abstract

Background: Recurrent implantation failure and spontaneous abortion are more prevalent in women of advanced maternal age (AMA) primarily due to increased rates of gamete and embryonic aneuploidy. Murine models demonstrate lower live birth rates from in-vitro cultured embryos versus those developed in-vivo. It follows that in-vitro culture may contribute to abnormal human embryonic development leading to implantation failure. Zygote Intrafallopian Transfer (ZIFT) may improve implantation rates by providing optimal conditions for early embryonic development.Objective: To determine whether ZIFT improves implantation rate in patients of AMA who previously failed traditional in-vitro fertilization-embryo transfer (IVF-ET).Materials and Methods: All patients ≥36 years of age at the time of their first IVF-ET, who failed to achieve a clinical pregnancy and subsequently underwent a ZIFT procedure over a four year period from 2004-2008 were included. Cycles involving egg donation and frozen embryos were excluded. The primary endpoint of the study was implantation rate.Results: Seven patients who underwent 10 IVF-ET cycles (mean 1.4 failed IVF-ET cycles) and nine ZIFT cycles were included in the analysis. The mean age at the time of the first IVF-ET was 39.0 ± 1.2 (36-43) and at the time of the first ZIFT 39.7 ± 1.1 (36-43) (P>0.05). A total of 39 embryos (mean 3.9 ± 0.5 embryos per ET, range 1-6) were transferred in the IVF-ET group versus 43 zygotes (mean 4.8 ± 0.3) zygotes per ZIFT, range 3-6) in the ZIFT group (P>0.05). Both implantation rates, 14/43 (32.6%) and 0/39 (0%), and clinical pregnancy rate per transfer, 6/9 (66.7%) versus 0/10 (0%), were significantly higher in the ZIFT versus IVF-ET group respectively (P<0.05). The multiple pregnancy rate in the ZIFT group was 3/6 (50%). Overall, 4/7 (57.1%) of the patients undergoing ZIFT achieved a clinical pregnancy.Conclusions: ZIFT is a viable option for women of AMA with previous IVF-ET failure. These results suggest that the intra-fallopian environment may be superior to in-vitro conditions for patients with a higher tendency to embryonic aneuploidy. Larger, prospective crossover trials are needed to verify these favorable results. Background: Recurrent implantation failure and spontaneous abortion are more prevalent in women of advanced maternal age (AMA) primarily due to increased rates of gamete and embryonic aneuploidy. Murine models demonstrate lower live birth rates from in-vitro cultured embryos versus those developed in-vivo. It follows that in-vitro culture may contribute to abnormal human embryonic development leading to implantation failure. Zygote Intrafallopian Transfer (ZIFT) may improve implantation rates by providing optimal conditions for early embryonic development. Objective: To determine whether ZIFT improves implantation rate in patients of AMA who previously failed traditional in-vitro fertilization-embryo transfer (IVF-ET). Materials and Methods: All patients ≥36 years of age at the time of their first IVF-ET, who failed to achieve a clinical pregnancy and subsequently underwent a ZIFT procedure over a four year period from 2004-2008 were included. Cycles involving egg donation and frozen embryos were excluded. The primary endpoint of the study was implantation rate. Results: Seven patients who underwent 10 IVF-ET cycles (mean 1.4 failed IVF-ET cycles) and nine ZIFT cycles were included in the analysis. The mean age at the time of the first IVF-ET was 39.0 ± 1.2 (36-43) and at the time of the first ZIFT 39.7 ± 1.1 (36-43) (P>0.05). A total of 39 embryos (mean 3.9 ± 0.5 embryos per ET, range 1-6) were transferred in the IVF-ET group versus 43 zygotes (mean 4.8 ± 0.3) zygotes per ZIFT, range 3-6) in the ZIFT group (P>0.05). Both implantation rates, 14/43 (32.6%) and 0/39 (0%), and clinical pregnancy rate per transfer, 6/9 (66.7%) versus 0/10 (0%), were significantly higher in the ZIFT versus IVF-ET group respectively (P<0.05). The multiple pregnancy rate in the ZIFT group was 3/6 (50%). Overall, 4/7 (57.1%) of the patients undergoing ZIFT achieved a clinical pregnancy. Conclusions: ZIFT is a viable option for women of AMA with previous IVF-ET failure. These results suggest that the intra-fallopian environment may be superior to in-vitro conditions for patients with a higher tendency to embryonic aneuploidy. Larger, prospective crossover trials are needed to verify these favorable results.