Sept. 4, 2008 -- Moms who deliver naturally may be more responsive to their newborn's cries than women who deliver via cesarean section, a study shows.
But experts caution that women who have C-sections should not feel like failures as mothers because they did not deliver vaginally. In recent years, the rate of C-section delivery in the U.S. has increased from about 4.5% of all deliveries in 1965 to 29.1% in 2006, according to information cited in the study.
The study is published in the October issue of the Journal of Child Psychology and Psychiatry.
"Just because moms who deliver vaginally respond better to their infant's cries does not mean they are better parents," says researcher James E. Swain, MD, PhD, a child and adolescent psychiatrist at the Yale University School of Medicine in New Haven, Conn. "Other factors play a role, including the whole lifetime experience of the mother, the presence of a supportive father, as well as other socioeconomic and cultural factors."
The researchers used brain scans called functional magnetic resonance imaging (fMRI) on 12 new moms two to four weeks following delivery to determine if the type of delivery affected how responsive they were to their newborn's cries.
The Role of Oxytocin
The six women who delivered vaginally showed more activity in certain areas of the brain linked to emotions and parenting behaviors compared to the six moms who had elective C-sections. The researchers suggest that vaginal birth stimulates the more rapid release of the "love hormone" oxytocin.
Oxytocin is released during active labor and delivery. It's been shown to be a factor in mother-child bonding.
Some research has linked C-section delivery with higher rates of postpartum depression, and this may be due to the discrepancies in oxytocin release. None of the women in the new study developed postpartum depression. The initial study was three weeks in duration, but unpublished, follow-up data spanning three to four months showed that the differences between the moms on MRI is less marked.
"Don't panic or think you did the wrong thing by having a C-section because it may be that these differences are just in the initial phases and it may take the oxytocin awhile to build up after a C-section delivery. Or maybe C-section moms may make up for it later with normal cuddling and hugging and nursing," Swain says. Breastfeeding is known to stimulate the release of oxytocin.
Going forward, the new findings may help doctors develop a screening test for risk of postpartum depression. "We can monitor the mother and father to see if certain brain areas are not as responsive to baby stimuli and then they can be a little more closely monitored and offered more support due to increased risk of depression," Swain says.
Calling the new study "a fascinating way of looking at the correlation between behavior and brain function," Manju Monga, MD, professor and division director of maternal-fetal medicine at the University of Texas Health Sciences Center in Houston, cautions that there are no definitive studies linking C-section delivery to higher rates of postpartum depression.
"The biggest stimulator of oxytocin release is breastfeeding," she says, which is unaffected by mode of delivery. "Maternal infant bonding has been shown to be associated with how long a mother is separated from their infant from birth and whether they initiate nursing right away. So rather than worry about mode of delivery, tell your physician that you want to room-in with the baby. And if you are planning to nurse, put baby to your breast in the recovery room," Monga suggests.
"These are very interesting preliminary results," says Donnica Moore, MD, a women's health expert based in Far Hills, N.J. "This study is not going to influence a doctor's recommendation for a C-section vs. a vaginal delivery. And there is big leap between cause and effect."
"The new findings may contribute to the feelings of women who have had C-section that they may have failed by not having a natural, vaginal delivery," she says. "The goal of labor and delivery is a healthy mother and a healthy baby."