Impact of Endometrial Preparation Protocols for Frozen Embryo Transfer on Live Birth Rates.

BACKGROUND: It has been reported that a natural cycle (NC) is similar to or even better than hormone replacement therapy (HRT) in patients with regular cycles who undergo frozen embryo transfer (FET). Hundreds of FETs are managed yearly in our clinic. Scheduling these cycles is critical in a busy unit like ours. This is why we have to prove if a NC really shows a better outcome than other endometrium preparation protocols. METHODS: Hence we carried out a prospective study between June 2011 and June 2012, which included 530 patients (570 FET cycles) randomly allocated to two study groups: Group 1 (n=280 cycles), artificial cycle (HRT); or group 2 (n=290 cycles), natural cycle. Natural cycles were later divided into two groups: 169 patients scheduled with human chorionic gonadotropin (hCG) and 121 with endogenous luteinizing hormone (LH) surge. The inclusion criteria were: age <39 years, regular menstrual cycles (26-35 days), and previous IVF cycle with embryo cryopreservation. The exclusion criteria were polycystic ovarian syndrome and endometriosis stage III/IV. RESULTS: No statistical differences were found in the baseline characteristics among groups, nor between implantation or ongoing pregnancy rates (30.8% HRT group; 32.7% hCG group; 34.5% LH surge group). However, a higher miscarriage rate was observed in the HRT group when compared to hCG or LH surge (21.2% versus 12.9% versus 11.1%, P<0.01). Live birth rates were similar among groups, as were perinatal outcomes, for rates of natural delivery and weight and length of newborns. CONCLUSIONS: We conclude that scheduling FET with HRT on weekdays and avoiding work overload at weekends prove efficient and safe in cycle outcome terms. Another reason for the convenience of an HRT protocol is having fewer visits to the clinic compared to natural cycle protocols.

Low-dose human chorionic gonadotropin versus estradiol/progesterone luteal phase support in gonadotropin-releasing hormone agonist-triggered assisted reproductive technique cycles: understanding a new approach.

It remains unclear how GnRH agonist (GnRHa) triggering affects the luteal phase, so we investigated the luteal phase after GnRHa triggering, supported with conventional E(2)/P with or without low-dose hCG. E(2)/P support, compared with low-dose hCG, induced a shorter luteal phase (11.2 ± 1.1 vs. 15.0 ± 1.6 days) and fewer subjective complaints (0 vs. 42%), whereas hCG caused more free fluid accumulation and enlarged ovaries than E(2)/P alone. Steroids and low-dose hCG differentially affected corpus luteum function, ovarian size, free fluid accumulation, and patient comfort.

In situ transmission electron microscopy and ion irradiation of ferritic materials.

The intermediate voltage electron microscope-tandem user facility in the Electron Microscopy Center at Argonne National Laboratory is described. The primary purpose of this facility is electron microscopy with in situ ion irradiation at controlled sample temperatures. To illustrate its capabilities and advantages a few results of two outside user projects are presented. The motion of dislocation loops formed during ion irradiation is illustrated in video data that reveals a striking reduction of motion in Fe-8%Cr over that in pure Fe. The development of extended defect structure is then shown to depend on this motion and the influence of nearby surfaces in the transmission electron microscopy thin samples. In a second project, the damage microstructure is followed to high dose (200 dpa) in an oxide dispersion strengthened ferritic alloy at 500 degrees C, and found to be qualitatively similar to that observed in the same alloy neutron irradiated at 420 degrees C.

Differential regulation of VEGF after final oocyte maturation with GnRH agonist versus hCG: a rationale for OHSS reduction.

In a prospective cohort study, we compared the effect of hCG and GnRH agonist triggering of final oocyte maturation on vascular endothelial growth factor production. Vascular endothelial growth factor follicular fluid concentration was significantly lower in response to GnRH agonist versus hCG, which may partially explain the absence of OHSS in these of women.

Letrozole administration during the luteal phase after ovarian stimulation impacts corpus luteum function: a randomized, placebo-controlled trial.

OBJECTIVE: To investigate the effect of letrozole-an oral aromatase inhibitor-on E(2), P, and LH levels when administered during the luteal phase after oocyte retrieval in IVF/intracytoplasmic sperm injection (ICSI) cycles. DESIGN: Prospective, randomized, placebo controlled trial. SETTING: University-affiliated private reproductive medicine center. PATIENT(S): Thirty oocyte donors undergoing standardized controlled ovarian hyperstimulation (COH) protocols. INTERVENTION(S): Patients were randomized after successful egg retrieval to receive either 2.5 mg of letrozole (Femara; Novartis, Barcelona, Spain) or a placebo (folic acid tablets). All donors were under intrauterine device (IUD) contraception. MAIN OUTCOME MEASURE(S): Serum E(2), P, and LH the day of hCG administration and days +4, +7 and +10 after ovum pick-up. RESULT(S): Donors had a comparable serum E(2) level on the day of hCG administration (1,858 vs. 2,143 pg/mL). Interestingly, levels dramatically dropped 4 days after egg retrieval, reaching a statistically significant lower level in those receiving letrozole (279 vs. 1,586 pg/mL). Again, at the next time points serum E(2) levels were significantly lower (day +7: 240 vs. 855 pg/mL and day +10: 40 vs. 448 pg/mL). No significant differences were observed in P levels, but LH serum concentrations were lower in the control group on day +7 (0.18 vs. 0.02 mIU/mL and day +10 (0.40 vs. 0.16 mIU/mL), when serum E(2) levels were higher. CONCLUSION(S): The administration of 2.5 mg of letrozole during the luteal phase has an impact on corpus luteum (CL) function. It reduces serum E(2) levels, which allows a faster recovery of LH concentration. This may be of interest not only for egg donors, but also in patients at high risk of ovarian hyperstimulation syndrome (OHSS) who freeze all their embryos or who cancel hCG administration to reduce the potential risk that high E(2) levels pose.