The researchers, led by Yale Child Study Center Assistant Professor James Swain, M.D., recruited two groups of parents from postpartum wards. One group of 12 mothers had caesarean sections and the other delivered naturally (vaginally). All women were interviewed and given brain scans two to three weeks after giving birth. During the brain scans, parents listened to recordings of their own baby's cry during the discomfort of a diaper change. The researchers then conducted interviews to assess the mothers' mood as well as their thoughts and parenting.

The team found that compared to mothers who delivered by caesarean section, those who delivered vaginally had greater activity in certain brain regions in response to their own baby's cry as measured by fMRI. These brain areas included cortical regions that regulate emotions and empathy, as well as deeper brain structures that contribute to motivation, and habitual thoughts and behaviors. The responses to their own baby's cry in some of these regions varied according to mood and anxiety.

Swain said that no parent in the small study developed clinical depression, making it hard to assess the significance of the findings without replication and follow-up studies. "I suspect that the parental brain is 'primed' by vaginal delivery and affected by neurohormonal factors such as oxytocin, a hormone linked to emotional connections and feelings of love," said Swain. "caesarean sections may alter these neurohormonal factors and increase the risk of problematic bonding and postpartum depression."

"These results provoke many questions and may help expectant mothers as they consider their options carefully," said Swain. "There are plenty of good reasons for caesarean sections, and we would not want our work to be misinterpreted as proving that mothers who opt for caesarean sections are destined for trouble. On the contrary, we hope to provoke support from family and perhaps health professionals after caesarean sections. In the future, it may be possible to prevent postpartum depression."

Swain is pursuing studies on populations at risk for postpartum mental health problems. He expects to undertake genetic studies in addition to brain imaging and interviews to improve basic understanding and to eventually translate the research into tailored treatments.

See Also: Babies Smiles and Mother's Brains

Source: EurekAlert (Press Release)