Setting: A private laboratory for assisted reproductive technology.Study Design: Retrospective evaluation of pregnancy outcomes following in vitro fertilization – embryo transfer with preimplantation genetic diagnosis-aneuploidy screening (IVF-ET / PGD-AS) in an unselected, chronologically consecutive group of patients of advanced maternal age with prior histories of recurrent pregnancy loss.Objective: To determine if selection of embryos by PGD-AS for recurrent pregnancy loss patients improves (lowers) their first trimester miscarriage rate in comparison to their reproductive histories.Materials and Methods: A total of nineteen patients were evaluated in this study. Their average maternal age was 39.4 years with average first trimester pregnancy losses prior to IVF-ET / PGD-AS per patient of 3.6 (79 losses / 100 clinical pregnancies = 79% pregnancy loss rate). All patients underwent ovulation induction using established protocols. Fertilization of oocytes was by conventional insemination or intracytoplasmic sperm injection as determined by “day of retrieval” semen parameters. One, or sometimes two, blastomeres were removed from all embryos biopsied on day 3 post-insemination and evaluated for ploidy of chromosomes 8,9,13,15,16,18,21,22 X and Y. Embryo transfer was performed generally on day 4, occasionally on day 5 post-insemination using 3-D / 4-D “real-time” ultrasound guidance. Averages of 2.5 embryos were transferred per patient. Pregnancy was confirmed by fetal cardiac activity.Results: Ten patients became pregnant from 22 IVF-ET / PGD-AS cycles for a pregnancy rate per retrieval of 45.5% (53% per transfer). One pregnancy was lost (4.5%) before the first trimester. One of twelve fetal heartbeats was lost, for a loss rate of 8%. The embryo implantation rate was 25%. Eleven babies were delivered from twelve initial sacs for a “take-home baby rate” of 50% per oocyte retrieval. There were no selective reductions.Conclusions: Screening preimplantation embryos for aneuploidy prior to embryo transfer appears to be an effective means of lowering the miscarriage rate in women who have experienced recurrent pregnancy loss. More studies are needed to define which patient categories, other than those wishing to avoid identified heritable mutations, benefit from preimplantation genetic diagnosis. Setting: A private laboratory for assisted reproductive technology. Study Design: Retrospective evaluation of pregnancy outcomes following in vitro fertilization – embryo transfer with preimplantation genetic diagnosis-aneuploidy screening (IVF-ET / PGD-AS) in an unselected, chronologically consecutive group of patients of advanced maternal age with prior histories of recurrent pregnancy loss. Objective: To determine if selection of embryos by PGD-AS for recurrent pregnancy loss patients improves (lowers) their first trimester miscarriage rate in comparison to their reproductive histories. Materials and Methods: A total of nineteen patients were evaluated in this study. Their average maternal age was 39.4 years with average first trimester pregnancy losses prior to IVF-ET / PGD-AS per patient of 3.6 (79 losses / 100 clinical pregnancies = 79% pregnancy loss rate). All patients underwent ovulation induction using established protocols. Fertilization of oocytes was by conventional insemination or intracytoplasmic sperm injection as determined by “day of retrieval” semen parameters. One, or sometimes two, blastomeres were removed from all embryos biopsied on day 3 post-insemination and evaluated for ploidy of chromosomes 8,9,13,15,16,18,21,22 X and Y. Embryo transfer was performed generally on day 4, occasionally on day 5 post-insemination using 3-D / 4-D “real-time” ultrasound guidance. Averages of 2.5 embryos were transferred per patient. Pregnancy was confirmed by fetal cardiac activity. Results: Ten patients became pregnant from 22 IVF-ET / PGD-AS cycles for a pregnancy rate per retrieval of 45.5% (53% per transfer). One pregnancy was lost (4.5%) before the first trimester. One of twelve fetal heartbeats was lost, for a loss rate of 8%. The embryo implantation rate was 25%. Eleven babies were delivered from twelve initial sacs for a “take-home baby rate” of 50% per oocyte retrieval. There were no selective reductions. Conclusions: Screening preimplantation embryos for aneuploidy prior to embryo transfer appears to be an effective means of lowering the miscarriage rate in women who have experienced recurrent pregnancy loss. More studies are needed to define which patient categories, other than those wishing to avoid identified heritable mutations, benefit from preimplantation genetic diagnosis.