Obstetric and neonatal outcomes after the transfer of vitrified-warmed blastocysts developing from nonpronuclear and monopronuclear zygotes: a retrospective cohort study.

OBJECTIVE: To evaluate the obstetric and neonatal outcomes after the transfer of vitrified-warmed single blastocysts developing from nonpronuclear (0PN) and monopronuclear (1PN) zygotes. DESIGN: Cohort study. SETTING: Affiliated hospital. PATIENT(S): This study was a retrospective analysis of 435 0PN and 281 1PN vitrified-warmed single blastocyst transfers, and 151 0PN and 75 1PN singletons, compared with 13,167 two-pronuclear (2PN) vitrified-warmed single blastocyst transfers and 4,559 2PN singletons, respectively. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Pregnancy rate (PR), abortion rate (AR), live birth rate (LBR), and singleton birthweight were the primary outcome measures. RESULT(S): PR, AR, and LBR were similar when compared between the 0PN and 2PN groups after vitrified-warmed blastocyst transfer. However, the 0PN group had a higher birthweights, higher z scores, and a greater proportion of very large for gestational age newborns. When comparing the 1PN and 2PN groups, we found that the PR was similar whereas the AR was higher and the LBR was lower. No differences were detected in the other neonatal outcomes. CONCLUSION(S): The results of the present study show that the transfer of 2PN blastocysts should be prioritized because of a higher AR and a lower LBR after 1PN blastocyst transfers and a higher birthweight after 0PN blastocyst transfers when compared with 2PN blastocyst transfers. Our data indicate the need for concern about the safety of 1PN and 0PN embryo transfers.

In vitro development and implantation rates of fresh and cryopreserved sibling zygotes.

OBJECTIVE: To compare the developmental potential of cryopreserved human zygotes after thawing to sibling zygotes that were transferred without cryopreservation. METHODS: Retrospective analysis of embryo data and pregnancy outcome for all in vitro fertilization (IVF) patients who had sufficient zygotes to allow fresh embryo transfer and cryopreservation of additional sibling zygotes for later use. RESULTS: Zygotes survived cryopreservation at a high rate (87%). After thawing, cryopreserved zygotes developed at rates similar to those of fresh zygotes. Pregnancy occurred at similar rates after replacement of fresh embryos (27.9%) or replacement of cryopreserved-thawed zygote-derived embryos (24.3%). CONCLUSIONS: Human embryos can be cryopreserved at the pronuclear zygote stage with little loss of developmental potential. Cryopreservation allowed a reduction in the number of embryos transferred during an IVF retrieval cycle, thereby reducing the occurrence of multiple pregnancy. The total cumulative pregnancy rate per retrieval cycle doubled when pregnancies from cryopreserved-thawed zygotes were added to those originating from fresh zygotes.

Assisted reproductive technology in the United States: 1999 results generated from the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry.

OBJECTIVE: To summarize the procedures and outcomes of ART initiated in the United States in 1999. DESIGN: Data were collected electronically by using the SART Clinical Outcome Reporting System software and submitted to the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry. PARTICIPANT(S): Three hundred sixty programs submitted data on procedures performed in 1999. Data were collated after November 2000 so that the outcome of all pregnancies established would be known. MAIN OUTCOME MEASURE(S): Incidence of clinical pregnancy, ectopic pregnancy, abortion, stillbirth, and delivery. RESULT(S): Programs reported initiating 88,077 cycles of ART treatment. Of these, 63,639 cycles involved IVF (with and without micromanipulation), with a delivery rate per retrieval of 29.4%; 838 were cycles of gamete intrafallopian transfer, with a delivery rate per retrieval of 27.9%; 945 were cycles of zygote intrafallopian transfer, with a delivery rate per retrieval of 29.8%. The following additional ART procedures were also initiated: 6,509 fresh donor oocyte cycles, with a delivery rate per transfer of 41.8%; 12,005 frozen embryo transfer procedures, with a delivery rate per transfer of 18.6%; 2,488 frozen embryo transfers using donated oocytes or embryos, with a delivery rate per transfer of 23.6%, and 821 cycles using a host uterus, with a delivery rate per transfer of 33.6%. In addition, 398 cycles were reported as combinations of more than one treatment type, 18 cycles as research, and 416 as embryo banking. As a result of all procedures, 21,904 deliveries were reported, resulting in 30,967 neonates. CONCLUSION(S): In 1999, more programs reported ART treatment and reported cycles increased significantly (7.5%) compared to 1998. In comparable cycle types, the overall success rate (deliveries per retrieval) increased by 0.4%, which represents an increase of 1.2% compared to the success rate for 1998.

Elective cryopreservation of embryos at the pronucleate stage in women at risk of ovarian hyperstimulation syndrome may affect the overall pregnancy rate.

The aim of this retrospective study was to assess the pregnancy outcome and incidence of severe ovarian hyperstimulation syndrome (OHSS) in patients at risk of developing OHSS who had embryo cryopreservation at pronucleate stage and deferred embryo transfer in a university-affiliated teaching hospital over a 5-year period. Elective embryo cryopreservation and deferred transfer in patients at risk of OHSS does not compromise the cumulative pregnancy rate per patient and also results in a low overall incidence of severe OHSS.

Aneuploid analysis of tripronuclear zygotes derived from in vitro fertilization and intracytoplasmic sperm injection in humans.

This study demonstrates that the diploid ratio of tripronuclear zygotes after intracytoplasmic sperm injection (ICSI) is significantly higher as compared with that after conventional IVF; the extra pronucleus of tripronuclear zygotes after ICSI are mostly from the second polar body, not from sperm.

Transvaginal embryo transfer during the zygote intrafallopian tube transfer procedure.

OBJECTIVE: Our purpose was to evaluate a tactile non-ultrasonographically directed approach to transvaginal tubal cannulation and embryo transfer during the zygote intrafallopian tube transfer procedure. STUDY DESIGN: We studied the application of the tactile approach to transvaginal tubal cannulation and embryo transfer in 68 consecutive zygote intrafallopian tube transfer cycles. RESULTS: The tactile approach to transvaginal tubal cannulation and subsequent embryo transfer was successful in 93% of couples. Pregnancy occurred in 16 of the 63 (25%) women undergoing a successful transvaginal embryo transfer. CONCLUSION: The tactile approach to transvaginal tubal cannulation was found to be easily learned and provided a safe and convenient method of tubal embryo transfer. This low-cost approach, which has application to transfer of both embryos and gametes, deserves further study.

The influence of advanced age on the outcome of assisted reproduction.

PURPOSE: Our purpose was to determine the influence of age on the outcome of assisted reproduction, with particular interest in women aged 40 years or older. METHODS: A retrospective review of the 779 patients enrolled in the Royal Hospital for Women Fertility Group fertility program between 1987 and 1994 was performed. The results for women aged 40 years or older were compared with those for women between 36 and 39 years and those younger than 36 years. The main outcome measures were pregnancy rate, pregnancy outcome, fertilization rate, and ovarian response. RESULTS: Compared with those in younger women, pregnancy rate, pregnancy outcome, fertilization rate, and ovarian response to controlled ovarian stimulation were significantly worse in women aged 40 years or older. CONCLUSIONS: The outcome of assisted reproduction in women of 40 years of age or older was extremely poor. Compared with those in younger women, pregnancy outcome and ovarian response to controlled ovarian stimulation were significantly worse in women of 40 years or more.

[The results of a program of in vitro fertilization and tubal embryo transfer (ZIFT)]. / Resultados de un programa de fertilización in vitro y transferencia de embriones a la trompa (ZIFT).

Twenty-one sterile couples, between September 1989, and August 1991, were treated for ovulation stimulation of their cycles, in order to practice in them, a in vitro fertilization and tube embryo transfer (ZIFT). Two protocols of ovulation induction were used, both with leuprolide acetate (Lupron), one in the luteal phase and the other in follicular phase and since the second or the fourth day of the cycle, respectively, gonadotropins were added (Metrodine and Pergonal). Out of all the twenty-nine initiated cycles, twenty-seven were aspirated (93.1%) and twenty-four reached an embryo transfer (82.8%). Seven clinic pregnancies were obtained (29.17% per transfer) and four deliveries (16.67% per transfer). The sterility period average was 69.64 +/- 36.6 months and the patients age average was 34.1 +/- 4.38 years. The global rate of fertilization was 63.53%. With luteal phase Lupron best results were got (pregnancy rate of 38.46% per transfer) and there were not considerable difference in the number of gonadotropins ampulla employed. When embryos were transfer to the tubes and the uteri the pregnant rate was 50% per transfer, in comparison to 18.75% when transfer was made only in the tubes.

GIFT, ZIFT, and related techniques.

This review focuses on the theoretical backgrounds for tubal gamete and zygote/embryo transfer, as well as the clinical results of gamete intrafallopian transfer (GIFT), which are compared with other non-fertilization procedures in infertile women with patent fallopian tubes. While GIFT and zygote intrafallopian transfer (ZIFT) probably result in a more synchronized entry of embryos into the uterine cavity, prospective, randomized studies have not shown these methods to be preferable to conventional in-vitro fertilization and embryo transfer. Nevertheless, co-culture with various cell types seems to yield more viable embryos with a high rate of implantation. The promising results with co-culture do not seem to be a cell- or species-specific phenomenon. This non-specific positive or negative conditioning effect of co-culture on embryo quality indicates that more optimal culture media for in-vitro fertilization can probably be devised. The requirements of laparoscopy and general anesthesia with GIFT have prompted the development of simpler methods based on fertilization in vivo. Various methods of artificial insemination combined with controlled ovarian hyperstimulation yield comparable results with GIFT in unexplained infertility. In endometriosis, GIFT seems to give better results compared with insemination techniques. Less invasive transcervical gamete and embryo transfer techniques have now been established, obviating the need for operating theater facilities.