Ovulation and birth after administration of progesterone trigger-two case reports.

PURPOSE: To determine whether using progesterone as a trigger of a gonadotropin surge will induce ovulation and a competent corpus luteum. METHODS: Patients were administered 5 or 10 mg of progesterone intramuscularly when the leading follicle reached preovulatory size. RESULTS: We demonstrate that progesterone injections result in classical ultrasonographic hallmarks of ovulation about 48 h later and the formation of a corpus luteum competent to support pregnancy. CONCLUSION: Our results support further exploration of using progesterone to trigger a gonadotropin surge in assisted human reproduction.

Luteinizing hormone-independent rise of progesterone as the physiological trigger of the ovulatory gonadotropins surge in the human.

The current ovarian cycle paradigm postulates that ovulation is triggered by a critically sustained elevation of estradiol. However, an in-depth look into the published data reveals considerable uncertainty about the relative roles of progesterone and estradiol in the ovulation process.This review provides compelling evidences that the role of estradiol in ovulation has been misinterpreted and that the true physiological trigger of ovulation is a luteinizing hormone-independent preovulatory progesterone surge in the circulation to approximately 0.5 ng/mL. Furthermore, the current work reconciles the ability of progesterone to trigger ovulation, with its well-established ability to block ovulation during pregnancy, or when administered in the form of a synthetic progestin in birth control formulations and with experimental data that estradiol benzoate triggers ovulation in the complete absence of progesterone.

Reconstruction of ooplasm recipient oocytes with frozen-thawed donor microcytoplasts and influence on the microtubular spindle.

OBJECTIVE(S): To cryopreserve micromanipulated ooplast segments (microcytoplasts) from mouse oocytes, compare microcytoplast and parent or recipient oocyte fusion performed within or without the zona pellucida, compare electrofusion of fresh or frozen oocyte with frozen-thawed microcytoplasts, and assess spindle integrity after reconstruction of oocytes. DESIGN: Prospective experimental study. SETTING: University-based experimental laboratory. ANIMAL(S): Mouse (MII) oocytes obtained after superovulation (n = 363). INTERVENTION(S): Micromanipulation of oocytes (n = 363) into microcytoplasts (n = 181), cryopreservation of microcytoplasts along with parent and sibling control oocytes (n = 182), reconstruction by electrofusion of microcytoplast and parent or recipient oocyte performed with (group A, n = 35) or without a zona pellucida (group B, n = 32), comparison of electrofusion of fresh oocyte (group C, n = 40) or frozen oocyte (group D, n = 36) with frozen-thawed microcytoplasts fused within zona, and assessment of spindle morphology of reconstructed oocyte. MAIN OUTCOME MEASURE(S): Post-thaw survival, success of fusion, and spindle integrity as assessed by immunostaining. RESULT(S): Higher success of post-thaw fusion was seen in group A (91.4%) compared with group B (56.2%). The post-thaw fusion of microcytoplasts with either fresh or frozen oocytes was not significantly different. Spindle integrity was 82.5% in group C as compared with 47.2% in group D. CONCLUSION(S): Microcytoplasts created from oocytes can be successfully cryopreserved, thawed, and used to reconstruct oocytes with intact spindles.