<P> As measured on women undergoing in vitro fertilization, a longer menstrual cycle length is associated with higher pregnancy and delivery rates, even after age adjustment . Delivery rates after IVF have been estimated to be almost doubled for women with a menstrual cycle length of more than 34 days compared with women with a menstrual cycle length shorter than 26 days . A longer menstrual cycle length is also significantly associated with better ovarian response to gonadotropin stimulation and embryo quality . </P> <P> The different phases of the menstrual cycle correlate with women's moods . In some cases, hormones released during the menstrual cycle can cause behavioral changes in females; mild to severe mood changes can occur . The menstrual cycle phase and ovarian hormones may contribute to increased empathy in women . The natural shift of hormone levels during the different phases of the menstrual cycle has been studied in conjunction with test scores . When completing empathy exercises, women in the follicular stage of their menstrual cycle performed better than women in their midluteal phase . A significant correlation between progesterone levels and the ability to accurately recognize emotion was found . Performances on emotion recognition tasks were better when women had lower progesterone levels . Women in the follicular stage showed higher emotion recognition accuracy than their midluteal phase counterparts . Women were found to react more to negative stimuli when in midluteal stage over the women in the follicular stage, perhaps indicating more reactivity to social stress during that menstrual cycle phase . Overall, it has been found that women in the follicular phase demonstrated better performance in tasks that contain empathetic traits . </P> <P> Fear response in women during two different points in the menstrual cycle has been examined . When estrogen is highest in the preovulatory stage, women are significantly better at identifying expressions of fear than women who were menstruating, which is when estrogen levels are lowest . The women were equally able to identify happy faces, demonstrating that the fear response was a more powerful response . To summarize, menstrual cycle phase and the estrogen levels correlates with women's fear processing . </P> <P> However, the examination of daily moods in women with measuring ovarian hormones may indicate a less powerful connection . In comparison to levels of stress or physical health, the ovarian hormones had less of an impact on overall mood . This indicates that while changes of ovarian hormones may influence mood, on a day - to - day level it does not influence mood more than other stressors do . </P>

At what point in menstrual cycle is estrogen highest