Caring for an infant is challenging for any mother -- but especially so for women with postnatal depression, which may lead to adverse effects on child outcomes.
Current evidence on postnatal depression and parenting -- including preliminary data on the role of the hormone oxytocin -- is reviewed in the January/February issue of Harvard Review of Psychiatry. The journal is published by Wolters Kluwer.
Interventions for mothers with postnatal depression can improve parenting behaviors, according to the research review by Beth L. Mah, PhD, of Mothers and Babies Research Centre, Hunter Medical Research Institute, in New Lambton Heights, NSW, Australia. Hormone therapy with oxytocin might be a useful part of those treatment approaches, but more study is needed to define its risks and benefits.
Postnatal depression is clearly linked to poorer parenting behaviors, based on the results of 33 studies. "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," Dr. Mah writes.
Several studies 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," according to Dr. Mah.
Oxytocin -- a hormone that plays important roles in labor and breast-feeding -- also seems to have significant effects on parenting. In 13 studies, higher oxytocin levels were associated with parental behaviors likely to promote bonding. For example, mothers showed increased levels of oxytocin after affectionate contact with their infant. Some studies have suggested that parental behaviors may improve after treatment with oxytocin.
That raises the possibility that oxytocin might influence parenting in mothers with postnatal depression. So far, 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," Dr. Mah writes, "but more research is needed to establish its safety because of the uncertain impact of oxytocin upon maternal mood."
She highlights 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. Dr. Mah concludes, "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."