Embryo freezing for preventing Ovarian Hyperstimulation Syndrome

The rising incidence of heterotopic pregnancy: Current perspectives and associations with in-vitro fertilization

Heterotopic pregnancy is the simultaneous occurrence of an intrauterine and ectopic pregnancy. This study aims to review the current literature regarding heterotopic pregnancy with a focus on its diagnosis and associations with in-vitro fertilization (IVF). Studies have shown that ovarian hyperstimulation syndrome and multiple embryo transfer during IVF are associated with an increased risk of heterotopic pregnancy. Tubal abnormalities such as pelvic inflammatory disease and previous tubal or abdomino-pelvic surgery have also been identified as risk factors. Diagnosis is challenging as the falsely reassuring presence of an intrauterine fetus frequently delays early intervention. Treatment should be individualised, but is often prompt surgical intervention, and focuses on terminating the ectopic pregnancy while minimizing harm to the mother and intrauterine fetus.

Fertility preservation in reproductive-age women facing gonadotoxic treatments

BACKGROUND

Advancements in the treatments for cancer and autoimmune and other hematologic conditions continue to improve survival and cure rates. Despite those changes, various gonadotoxic agents and other treatments can still compromise the future fertility of many women. Progress in medical and surgical reproductive technologies has helped to offset the reproductive consequences of the use of gonadotoxic therapies, and allows for future fertility and normal pregnancy.

METHODS

A review of the literature was performed to outline the pathophysiology of gonadotoxicity from various treatments. The success of fertility preservation, fertility sparing, and cryopreservation options are reviewed. Barriers and facilitators to referral and oncofertility treatment in Canada are also outlined.

RESULTS

According to the quality of the evidence, recommendations are made for fertility assessment, patient referral, cryopreservation, and other assisted reproductive technologies.

CONCLUSIONS

To ensure ongoing fertility in women undergoing gonadotoxic treatments, assisted reproductive technologies can be combined with a multidisciplinary approach to patient assessment and referral.

A unique human chorionic gonadotropin antagonist suppresses ovarian hyperstimulation syndrome in rats

Ovarian hyperstimulation syndrome (OHSS) is a complication of in vitro fertilization associated with physiological changes after hCG administration to induce final oocyte maturation. It presents as widespread increases in vascular permeability and, in rare cases, results in cycle cancellation, multi-organ dysfunction, and pregnancy termination. These physiological changes are due primarily to activation of the vascular endothelial growth factor (VEGF) system in response to exogenous human chorionic gonadotropin (hCG). An hCG antagonist (hCG-Ant) could attenuate these effects by competitively binding to the LH/CG receptor, thereby blocking LH activity in vivo. We expressed a form of hCG that lacks three of its four N-linked glycosylation sites and tested its efficacy as an antagonist. The hCG-Ant binds the LH receptor with an affinity similar to native hCG and inhibits cAMP response in vitro. In a rat model for ovarian stimulation, hCG-Ant dramatically reduces ovulation and steroid hormone production. In a well-established rat OHSS model, vascular permeability and vascular endothelial growth factor (VEGF) expression are dramatically reduced after hCG-Ant treatment. Finally, hCG-Ant does not appear to alter blastocyst development when given after hCG in mice. These studies demonstrate that removing specific glycosylation sites on native hCG can produce an hCG-Ant that is capable of binding without activating the LH receptor and blocking the actions of hCG. Thus hCG-Ant will be investigated as a potential therapy for OHSS.

Cumulative first live birth after elective cryopreservation of all embryos due to ovarian hyperresponsiveness

OBJECTIVE

To estimate cumulative chance for first live birth after elective pronuclear stage cryopreservation of all embryos due to ovarian hyperresponsiveness.

DESIGN

Retrospective analysis with longitudinal follow-up.

SETTING

Academic hospital.

PATIENT(S)

Thirty subjects with elective cryopreservation of all embryos due to ovarian hyperresponsiveness.

INTERVENTION(S)

Elective cryopreservation of all embryos at the pronuclear stage (n = 30) and subsequent cryopreserved-thawed ET (n = 51).

MAIN OUTCOME MEASURE(S)

Cumulative chance for first live birth.

RESULT(S)

Cumulative chance for first live birth was 77% when analyzed by intention to treat and 82% by treatment with ET. Nearly 40% of live births were multiple.

CONCLUSION(S)

Cumulative first live birth increased with repetitive ET after elective pronuclear stage cryopreservation of all embryos due to ovarian hyperresponsiveness. Multiple births, however, were frequent. In the context of initial ET attempts in young women, transfer of no more than two cryopreserved-thawed embryos is advised.