Ethinyl Estradiol 6 [KLH]

A dose-response study was made of the broad-spectrum gonadal steroid agonist tibolone (TBL) on lordosis behavior in estradiol benzoate (EB: 5 mu g) primed rats. Doses of TBL (0, 1, 4, and 16 mu g) were infused to the right lateral ventricle 2 h before testing. The highest dose increased lordosis quotients significantly at 240 min and 360 min following infusion. However, the intensity of lordosis was weak. In experiment 2, the TBL dose of 16 mu g was selected to determine whether tamoxifen (TMX), RU486, or antide could modify the lordosis response to TBL. Infusions of the three compounds, before TBL, significantly attenuated the TBL-induced facilitation of lordosis. The results suggest that TBL stimulates lordosis by activating estrogen, progesterone, and may do so by downstream stimulation of GnRH release. The physiological role TBL plays in controlling lordosis behavior remains to be determined.

Objective: To study the effect of frozen embryo transfer (FET) preparation protocol on incidence of subchorionic hematoma (SCH) and serum hormone levels. Design: Retrospective cohort study. Setting: University-affiliated fertility center. Patient(s): Patients who underwent FET at the New York University Langone Fertility Center. Intervention(s): None. Main Outcome Measure(s): The primary outcome was incidence of SCH by protocol in FET cycles. Result(s): There were 1,273 FET cycles that met criteria for inclusion. The frequency of SCH was lower in natural compared with pro- grammed cycles (P< .05; relative risk = 0.4 [0.27-0.78]; odds ratio 0.4 [0.23-0.75]). Serum estrogen level was higher in programmed compared with natural cycles on day of progesterone initiation (P< .001) and cycle day 28 (P< .001). However, serum estrogen levels at the same time points were not associated with formation of SCH in programmed or natural cycles. Conclusion(s): This is the first study to evaluate the formation of SCHs by FET protocol type. Our results highlight that high serum estradiol levels do not independently lead to an increase in rate of SCH. Further research must be done to understand other clinical, or perhaps molecular, differences between natural and programmed FET cycle preparations that can be better associated with SCH formation. (C) 2020 by American Society for Reproductive Medicine.