Oxytocin's Role in Postnatal Depression Still Unclear

In a new analysis investigating the effects of postnatal depression (PND) on parenting behaviors, researchers have found perplexing results regarding the effects of the hormone oxytocin on mood in new mothers.

Oxytocin, sometimes known as the “cuddle hormone” plays an important role in labor and breast-feeding. It also appears to have significant effects on parenting.

The findings show that new moms with naturally higher levels of oxytocin tend to have fewer symptoms of depression; however, moms who are treated with oxytocin actually see an increase in depressive symptoms. This suggests that much more research is needed to better understand the benefits and risks of oxytocin.

Based on the analysis of 33 studies, postnatal depression is clearly linked to poorer parenting behaviors. Children cared for by mothers with postnatal depression are at increased risk of developing psychiatric disorders and developmental problems. Postnatal depression affects 10 to 20 percent of new mothers.

“Compared to nondepressed controls, mothers with PND interact with their infants less sensitively, report feeling less competent, and less often choose recommended practical parenting strategies,” writes Dr. Beth L. Mah, Ph.D., of Mothers and Babies Research Centre of Hunter Medical Research Institute in Australia.

Several of the studies in the analysis had evaluated treatment programs aimed at improving parenting in mothers with postnatal depression. While the studies varied in terms of the type of treatment and the way the results were assessed, “Psychological interventions for mothers with postnatal depression generally have positive effects on mother-infant interactions,” said Mah.

Hormone therapy with oxytocin might be a useful part of those treatment approaches, but the findings have been inconsistent. In 13 studies, higher natural levels of oxytocin were associated with parental behaviors likely to promote bonding. For example, mothers showed increased levels of oxytocin after affectionate contact with their infant.

This has raised the possibility that oxytocin might influence parenting in mothers with postnatal depression. So far, however, only four studies have looked at the relationship between postnatal depression and oxytocin. Two studies reported that mothers with lower oxytocin levels during pregnancy had higher scores for depressive symptoms.

The other two studies were randomized trials of oxytocin treatment: one in women with dysfunctional labor and one in women with postnatal depression. In both studies, depressive symptoms actually increased after treatment with oxytocin.

Thus the research so far has yielded divergent results: women with higher natural oxytocin levels have better mood, but administration of oxytocin results in poorer mood.

“Oxytocin is potentially useful in improving parental behaviors of mothers with postnatal depression,” Mah writes, “but more research is needed to establish its safety because of the uncertain impact of oxytocin upon maternal mood.”

She highlighted priorities for future research including higher-quality data on how postnatal depression affects parenting and better tools for diagnosing postnatal depression, assessing parenting, and measuring oxytocin levels.

“Perhaps the most important challenge is to determine whether oxytocin could be used as an adjunctive treatment to improve mother-infant relationships that are affected by the mother’s postnatal depression or other psychiatric conditions,” Mah said.

The findings are published in the Harvard Review of Psychiatry.

Source: Wolters Kluwer Health