Recent findings from a team of American researchers indicate that the severity of women\u2019s PTSD symptoms typically changes throughout the normal course of the monthly menstrual cycle. Compared to their male counterparts, women exposed to highly dangerous or life-threatening circumstances have sharply elevated chances of developing the symptoms of post-traumatic stress disorder (PTSD). In a study published in January 2015 in the Journal of Traumatic Stress, researchers from three U.S. institutions examined the impact that predictable changes in monthly menstruation have on the seriousness of the PTSD symptoms experienced by any given woman. These researchers concluded that PTSD\u2019s effects in women are largely linked to specific phases of the menstrual cycle. PTSD in Women According to figures compiled by the U.S. Department of Veterans Affairs\u2019 National Center for PTSD, about 20 percent of all American women exposed to a highly traumatic set of circumstances will have diagnosable symptoms of post-traumatic stress disorder 30 days or more after their trauma exposure. By comparison, just 8 percent of all American men will develop PTSD symptoms after exposure to the same types of circumstances. For both men and women, known factors in the onset of PTSD include surviving a natural disaster, surviving a physical assault or rape, surviving combat participation or combat exposure, surviving or witnessing a terror attack, surviving a major accident and having a childhood history of sexual or physical abuse. Compared to men, women typically have a much higher rate of exposure to rape and other forms of sexual assault. In turn, sexual assault is known for its ability to act as a trigger for the eventual development of post-traumatic stress disorder. These facts partially explain women\u2019s higher risks for PTSD. An additional factor is women\u2019s relatively pronounced tendency to blame themselves for exposure to sexual attacks and other contributing factors to a damaging stress reaction. Apart from those individuals who experience sexual assaults, groups of trauma-exposed women with especially elevated PTSD risks include individuals with a prior history of mental health problems and individuals who lack access to a well-developed social support network. The Menstrual Cycle The menstrual cycle is the term commonly used to describe the monthly changes in a woman\u2019s reproductive system that begin with egg production and end with the shedding of the blood-thickened lining inside the uterus (unless sperm fertilizes an egg). Specific stages of the menstrual cycle include the follicular phase (marked by the development of an egg inside the ovaries) and the luteal phase (the beginning of which is marked by ovulation, or the release of an egg from the ovaries). Impact on PTSD Severity In the study published in the Journal of Traumatic Stress, researchers from the National Center for PTSD, the Boston University School of Medicine and the Veterans Administration used a small-scale project involving 49 women to gauge the impact that various phases of the monthly menstrual cycle have on any given woman\u2019s PTSD symptoms. All of the participating women were previously exposed to highly traumatic events capable of triggering PTSD; some of the women had developed the disorder while others had not. In both groups, the researchers looked at the severity of any trauma-related reactions during the follicular phase and luteal phase of monthly menstruation. After analyzing the gathered data, the researchers concluded that women\u2019s trauma reactions are significantly more severe during the follicular phase of menstruation. This finding applies to psychological symptoms in general and symptoms of phobia-related anxiety and depression in particular. The researchers also concluded that, compared to trauma-exposed women who don\u2019t develop PTSD, trauma-exposed women who do develop the disorder experience substantially heightened symptoms of phobia-related anxiety during the follicular phase of menstruation. Among the study participants, the presence of PTSD during this phase of menstruation increased the impact of phobia-related anxiety by roughly 63 percent. The study\u2019s authors note that women unaffected by PTSD usually experience roughly equal amounts of phobia-related anxiety during the follicular and luteal phases of monthly menstruation. This means that phobic reactions in women with PTSD may largely account for the overall spike in anxiety observed during menstruation\u2019s follicular phase. All told, the researchers believe that fear-\/phobia-related reactions of women with PTSD rise sharply during the opening stages of the menstrual cycle.