When my own daughter was born by Caesarean section delivery, I was surprised how uninvolved I was in the process. My body was numb, and my view of the surgery was blocked by a sheet. When I finally heard a baby cry, it took a minute for me to realize that the sound belonged to my own baby.

That’s why I was particularly interested to read of new research showing that the method of delivery seems to influence how a mother’s brain responds to the cries of her own baby. The brains of women who have natural childbirth appear to be more responsive to the cries of their own babies, compared to the brains of women who have C-section births.

The finding is based on brain imaging scans conducted two to four weeks after delivery among just 12 women, half of whom had vaginal births and half of whom gave birth by C-section. The study, published in The Journal of Child Psychology and Psychiatry, found that the cry of a woman’s own baby triggered significant responses in several parts of the brain related to sensory processing, empathy, arousal, motivation, reward and habit-regulation. The effect was greatest in the brains of women who had delivered vaginally compared to those women who delivered their babies by C-section.

The conclusions that can be drawn from the study are limited because it involved so few women. However, it does support the theory that C-section birth may result in slight delays in attachment, putting those women at slightly higher risk for postpartum depression.

Lead author Dr. James Swain of Yale University’s child study center said the mode of delivery has been associated with decreased maternal behaviors in animals and a trend for increased postpartum depression in humans. It’s estimated that about 30 percent of births in the United States are delivered by C-section, the study says.

“Our results support the theory that variations in delivery conditions, such as with cesarean section, which alters the neurohormonal experiences of childbirth, might decrease the responsiveness of the human maternal brain in the early postpartum,” Dr. Swain said. “This work could lead to early detection of families at risk for postpartum depression and attachment problems and form a model for testing interventions.”

It’s important to note that the study measured only short-term differences in brain patterns following childbirth. There’s no evidence that delivery method has any long-term implications on a woman’s ability to parent or bond with her child or recognize her baby’s cry.

Within a few hours of my own C-section, I quickly figured out the pain medication the doctor was giving me was interfering with my ability to be alert and focused on my baby. Once I quit the pain drugs, I was surprised and delighted at how distinctive and unique the cry of my own baby sounded to me.

http://well.blogs.nytimes.com/2008/09/05/delivery-method-affects-brain-response-to-babys-cry/