The study published in the journal Cancer Research, also found that the link between PTSD and ovarian cancer remained for the most aggressive forms of ovarian cancer.
"In light of these findings, we need to understand whether successful treatment of PTSD would reduce this risk and whether other types of stress are also risk factors for ovarian cancer," said co-author Andrea Roberts from Harvard University.
To better understand how PTSD may influence ovarian cancer risk, researchers analysed data from the Nurses' Health Study II, which tracked the health of tens of thousands of women between 1989-2015 through biennial questionnaires and medical records.
Participants were asked about ovarian cancer diagnosis in each questionnaire, and information was validated through a review of medical records.
In 2008, 54,763 Nurses' Health Study II participants responded to a supplemental questionnaire focused on lifetime traumatic events and symptoms associated with those events.
Women were asked to identify the event they considered the most stressful, and the year of this event. They were also asked about seven PTSD symptoms they may have experienced related to the most stressful event.
Based on the responses, women were divided into six groups: no trauma exposure; trauma and no PTSD symptoms; trauma and one to three symptoms; trauma and four and five symptoms; trauma and six-seven symptoms; and trauma, but PTSD symptoms unknown.
After adjusting for various factors associated with ovarian cancer, including oral contraceptive use and smoking, the researchers found that women who experienced six-seven symptoms associated with PTSD were at a significantly higher risk of ovarian cancer than women who had never been exposed to trauma.
Women with trauma and four-five symptoms were also at an elevated risk, but the risk did not reach statistical significance.
The study also showed that women who experienced six-seven symptoms associated with PTSD were at a significantly higher risk of developing the high-grade serous histotype of ovarian cancer the most common and aggressive form of the disease.
( With inputs from IANS )