Women who are stressed have more pronounced PMS symptoms, according to NIH research.

Women who felt stressed two weeks before the beginning of menstruation were two to four times more likely to report moderate to severe PMS symptoms than women who did not feel stressed, according to the study by NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development. Researchers from the University of Massachusetts-Amherst and the State University of New York Buffalo also participated in the study, which was published online in the Journal of Women's Health.

PMS is a group of physical and psychological symptoms that occur around the time of ovulation. They include anger, anxiety, mood swings, depression, fatigue, decreased concentration, breast swelling and tenderness, general aches and abdominal bloating.

The researchers issued questionaires to 259 women ages 18 to 44. The women didn't have any long-term health conditions and were not using birth control pills or taking other hormones.

Each women was provided with an at-home fertility monitor to follow different phases of their menstrual cycle. They were then asked questions about their stress levels during their four-week cycle.

Women whose responses indicated they were stressed were more likely to report more severe levels of psychological symptoms, such as depression, anxiety or crying spells. Physical symptoms such as body aches, abdominal bloating, lower back pain and cravings for salty or sweets foods were also greater.

Women reporting high stress levels were two to four times more likely to have moderate or severe PMS symptoms, the study found.

The study followed women over several menstrual cycles and found PMS was worse during those cycles when they were stressed.

There are medications that can be used to treat PMS, but the researchers said further studies should look at how stress reduction techniques might help PMS.

So try some yoga or meditation next time you're feeling stressed before your cycle.