UNC researchers study ‘love hormone’ ties to breastfeeding, postpartum depression

relder@newsobserver.comJune 21, 2013 

  • Volunteers wanted

    Pregnant women between the ages of 18 and 35 who are planning to breastfeed are needed to participate in the research study “Mood, Mother and Infant.”

    Volunteers will receive a free medical evaluation and are required to make four visits to UNC-Chapel Hill.

    To volunteer or learn more, visit http://j.mp/14tCyPN, call 919-843-8084, or email Brenda Pearson at bpearson@med.unc.edu.

    To learn more about postpartum mood disorders, go to postpartumprogress.org.

— Anxiety and fear overshadowed the joys of motherhood for Julie Zola shortly after she brought her baby home from UNC Hospital.

“It hit me like a train: shortness of breath, dizziness, heart palpitations. I was terrified,” Zola said, recalling the panic attacks that began about two weeks after childbirth and continued off and on for several months.

Her anxiety improved, Zola noted, whenever she sat down to nurse her newborn, a reaction doctors attribute to oxytocin, a hormone that surges whenever mothers breastfeed their infants.

The powerful effect of oxytocin on the emotions and behaviors of new mothers is the subject of a five-year, $2.9 million study by researchers at UNC-Chapel Hill. They plan to follow 230 women beginning in late pregnancy through their child’s first birthday, said Samantha Meltzer-Brody, associate professor of psychiatry at UNC’s Center for Women’s Mood Disorders in Chapel Hill.

Oxytocin – sometimes called the “love hormone” because of its role in empathy and emotional well-being – is especially important for mothers of infants because it triggers breast milk to flow during breastfeeding, fosters bonding between mother and child, and may also guard against depression and anxiety, Meltzer-Brody said.

Alison Stuebe, an obstetrician-gynecologist at UNC’s Gillings School of Global Public Health, led a pilot study of 52 mothers of infants, which found that depressed mothers produced less oxytocin during breastfeeding. That research, published in April in the Journal of Women’s Health, paved the way for the larger study, funded by the National Institutes of Health.

“That study raised the interesting question of whether there is something wrong with a woman’s oxytocin production that is making her anxious and depressed, or is the anxiety repressing the oxytocin,” Stuebe said.

Researchers also want to learn more about oxytocin’s effects on infant-mother bonding, said Cathi Propper, a psychologist at the Center for Developmental Science at UNC who is part of the study team.

“We are really interested in seeing how sensitive and responsive mothers are during their babies’ first few months of life,” Propper said. “That experience determines a child’s expectations and is linked to things later in life, like social and emotional functioning, cognitive functioning and tons of other potentially positive outcomes.”

Propper said studies have shown women who suffer from mood disorders are less likely to notice their infants’ signals of distress or readiness to play.

“Depressed moms often have a flat affect – not responding, smiling and showing interest the way that non-depressed moms do,” Propper said.

The researchers will evaluate hormone levels during breastfeeding, as well as observe the mothers interacting with their babies.

“Our hypothesis is that moms whose oxytocin levels aren’t as high as they should be will have less positive interactions with their babies and find it harder to pick up on their cues,” Stuebe said.

Meltzer-Brody said the findings will be used to help develop better screening methods and treatment for postpartum mood disorders. Current treatments include antidepressant medications and talk therapy, which Zola said helped put her back on track by the time her son was a few months old.

The American Academy of Pediatrics journal in March reported that 17 percent of new mothers experience anxiety disorders and 6 percent have depression. Altogether, about 15 percent of women who give birth report signs of a mood disorder, which could be triggered by drops in estrogen and progesterone that occur after birth, Stuebe said.

Other risk factors include a previous history of mood disorders, thyroid imbalance, complications of pregnancy or childbirth, lack of support at home, or childhood trauma, especially childhood sexual trauma that can permanently alter mood chemistry.

Meltzer-Brody, who directs UNC’s perinatal psychiatry program, said the research proposal came together after she and Stuebe realized many women who are suffering from postpartum depression also have difficulty breastfeeding.

Stuebe said lower oxytocin levels may make breastfeeding less enjoyable and may discourage women from continuing the practice, which is recommended through a child’s first year for its nutritional advantages and support for the autoimmune system.

“The conventional wisdom is that breastfeeding reduces postpartum depression – yet we see tremendous overlap between moms who struggle with breastfeeding and moms who have postpartum depression or anxiety symptoms,” Stuebe said.

In North Carolina, 68 percent of new mothers breastfeed initially, but that figure drops to 38 percent at six months, according to the Centers for Disease Control and Prevention. Nationally, 77 percent of new mothers start out breastfeeding, and 47 percent continue through the first six months.

CDC doctors note that breastfeeding facilitates bonding, because it requires moms to stop what they are doing, relax and hold their infants. The simple act of skin-to-skin contact has been found to boost oxytocin.

Elder: 919-829-4528

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