Women suffering from the pain following childbirth are more likely to develop postpartum depression, a new study said Sunday.

The latest research results, which were revealed at an ongoing annual meeting of the American Society of Anesthesiologists (ASA) being held in downtown San Francisco on Oct 13-17, for the first time differentiate postpartum pain from labor and delivery pain and identify it as a the major culprit of postpartum depression.

The study, led by Jie Zhou, its lead author and assistant professor of anesthesia at Brigham and Women's Hospital and Harvard Medical School, Boston, made a detailed analysis of the specific part of the labor process, and concluded that postpartum depression is more likely linked to the pain from after childbirth, instead of before or during delivery.

"For many years, we have been concerned about how to manage labor pain, but recovery pain after labor and delivery often is overlooked," said Zhou.

Zhou's research team examined pain scores calculated from the start of labor to hospital discharge for 4,327 first-time mothers delivering a single child, both vaginally or by cesarean delivery (C-section), at Brigham and Women's Hospital between June 1, 2015 and Dec 31, 2017.

They found postpartum depression was significantly connected with higher postpartum pain scores, particularly among the group of women who have delivered by C-section.

About one in nine women who have postpartum depressions often experienced symptoms of extreme sadness, low energy, anxiety, crying episodes, irritability and changes in sleep or eating patterns, statistics of the U.S. Centers for Disease Control and Prevention.

Zhou's study indicates that postpartum depression is more often to happen among women who were overweight or obese, suffering from a torn perineum, having a history of depression, anxiety or chronic pain, or having a less healthy condition of their newborn babies.

"Our research suggests we need to focus more on helping new mothers manage pain after the baby is born," Zhou said, underscoring the importance of managing pain during recovery.