H. Anthony Pattinson

Outcome of thaw embryo transfer after cryopreservation of all embryos in patients at risk of ovarian hyperstimulation syndrome

OBJECTIVE To determine the incidence of ovarian hyperstimulation syndrome (OHSS) and subsequent pregnancy rates (PRs) if ET is delayed in patients at risk of OHSS by allocating all embryos to cryopreservation. DESIGN Retrospective analysis of clinical and laboratory data from 724 consecutive stimulated cycles of IVF. SETTING University hospital-based IVF program. PATIENTS Consecutive patients undergoing IVF between September 1989 and December 1992. MAIN OUTCOME MEASURES Fertilization rates, cryosurvival rates, subsequent PRs, and the occurrence of severe OHSS. RESULTS Ten of the 564 patients (1.8%) who had ET in the stimulation cycle developed severe OHSS. Sixty-nine patients had all embryos frozen because of the risk of OHSS, of which one (1.4%) developed severe OHSS. The subsequent PR after thaw transfer was 25.2% per transfer, with a cumulative PR per patient after additional thaw transfers of 40.6%. CONCLUSIONS Cryopreservation of all embryos and delayed ET in patients at risk of OHSS results in a low incidence of severe OHSS. Oocyte quality, fertilization rates, and cryosurvival of frozen embryos are equal to those for patients who have a normal stimulation profile. Subsequent thaw embryo replacements result in a satisfactory PR.

The mouse embryo culture system: improving the sensitivity for use as a quality control assay for human in vitro fertilization

OBJECTIVE To determine whether the mouse embryo culture system can be sensitized to provide improved differentiation of suboptimal culture media for in vitro fertilization. DESIGN Mouse embryo development in media prepared from one of three water sources were compared using embryos from two mouse strains, culturing embryos from either zygote or two-cell stage, and pretreating with either zona removal and/or cryopreservation. SETTING Academic research department, tertiary care referral center. RESULTS Embryos from CD1 mice were able to develop in suboptimal culture conditions, even when pretreated with zona removal or cryopreservation. Embryos from B6CBA/F1J mice were more sensitive to suboptimal culture conditions when harvested at the zygote stage than at the two-cell stage, and this sensitivity was improved after zona removal before culture. CONCLUSIONS The mouse embryo culture system has deficiencies as an assay of culture medium quality, but the sensitivity of the assay can be optimized by harvesting at the zygote stage from an appropriate strain and by zona pellucida removal before culture.

Exogenous control of the cycle simplifies thawed embryo transfer and results in a pregnancy rate similar to that for natural cycles

To determine if a satisfactory PR could be achieved in thawed ET using a simplified protocol, standard monitoring in the natural cycle was compared with a controlled preparation of the endometrium with exogenous E2 and P without hormonal or ultrasonographic monitoring. All patients had normal ovarian function, and no GnRH-a were administered. Pregnancy rates, ongoing PRs, and embryo implantation rates were similar in the two groups. The use of exogenous E2 and P without GnRH-a suppression to control the cycle for thaw ET is safe, convenient, and results in PRs at least as good as in the natural cycle. It may be of particular value in patients with an irregular cycle or in those for whom prolonged monitoring is undesirable.

Cervical Pregnancy Following In Vitro Fertilization: Evacuation After Uterine Artery Embolization with Subsequent Successful Intrauterine Pregnancy

Summary: A case is described in which a cervical pregnancy followed in vitro fertilization. Treatment was delayed at the request of the patient until the second trimester, and was successfully managed by preoperative bilateral angiographic uterine artery occlusion, surgical evacuation, and postoperative balloon tamponade. Subsequent embryo transfer of previously cryopreserved embryos resulted in a normal intrauterine pregnancy and delivery without complications. This case highlights the need for awareness of cervical pregnancy following in vitro fertilization and the success of management which preserves fertility.

Factors predicting outcome in 215 consecutive thawed embryo replacements

This retrospective study was undertaken to determine which factors were associated with outcome in thawed embryo replacement cycles. The number of embryos replaced and the response to exogenous ovarian stimulation in the original IVF cycle were significantly associated with the conception rate.