That might be because general anesthesia can delay breastfeeding and skin-to-skin interaction between the mother and infant, and often results in more acute and persistent pain after childbirth, researchers from Columbia University Mailman School of Public Health explained.
"These situations are often coupled with a new mother's dissatisfaction with anesthesia in general, and can lead to negative mental health outcomes," said Jean Guglielminotti, lead author and an assistant professor of anesthesiology at Columbia, in a news release.
The study, published in the journal Anesthesia and Analgesia, is the first to examine how specific types of anesthesia for cesarean delivery affect the risk of postpartum depression.
General anesthesia increased odds of postpartum depression
The researchers used hospital discharge records of cesarean delivery cases from New York state hospitals between 2006 and 2013. Out of the 428,304 cases they examined, 34,356 women -- or 8% -- received general anesthesia during delivery.
General anesthesia induces sleep, meaning that mothers won't be able to see, feel or remember anything during childbirth. It also prevents them from being able to see their child immediately after birth.
The study found that 1,158 of the women who received general anesthesia, or about 3%, experienced severe postpartum depression that required hospitalization. Women who had general anesthesia were also 54% more likely to experience postpartum depression and 91% more likely to have thoughts about suicide or self-harm, compared to those who had regional anesthesia such as spinal blocks or epidurals.
Women who had general anesthesia during C-sections were also older, and more often non-white and on Medicaid or Medicare, compared to those who had regional anesthesia, the study said.
The authors caution that their findings don't necessarily mean that general anesthesia causes postpartum depression.
"We don't want people to believe that general anesthesia is always bad," Guglielminotti told CNN. "It can be good in some situations, when you require an emergency C-section. What we're saying is that general anesthesia is not always good, and when it can [it should] be avoided."
General anesthesia is rarely used
General anesthesia for cesarean delivery is not the norm in North America.
Fewer than 5 out of every 100 C-sections in the US are done with general anesthesia, according to the Society for Obstetric Anesthesia and Perinatology.
When general anesthesia is used, it's typically in emergency C-sections or in cases when typical numbing anesthesia like spinal blocks or epidurals cannot be used, says Grace Lim, director of obstetric anesthesiology at UPMC Magee-Womens Hospital in Pittsburgh.
Emergency cesareans are more likely to be needed for babies who are pre-term or sick in some way, or for mothers with certain health problems, which Lim says could explain the increased odds of postpartum depression.
"Thus, the nature of the emergency delivery, rather than the general anesthetic itself, may be the real reason why these women end up with higher odds of depression," she wrote in an email to CNN.
About one in nine women nationally experience symptoms of postpartum depression, according to CDC research.