Depression is fairly common among parents of children younger than 12, with the risk being greatest in their children's first year of life, a new study suggests.

The findings, say researchers, bolster evidence that mothers are more vulnerable to developing depression soon after giving birth, versus other periods of their life.

They also suggest that new fathers, a group much less studied than mothers, face a higher-than-normal depression risk as well.

The study included nearly 87,000 UK couples whose medical records were followed starting from the birth of their child and for up to 12 years afterward.

Over that time, 39 percent of mothers and 21 percent of fathers had at least one bout of clinical depression, based on diagnoses of depression or prescriptions for antidepressants in their medical records.

For both parents, the risk was highest during the first year of their child's life, the study found.

Nearly 14 percent of moms developed depression in their baby's first year, which is in line with rates of maternal postpartum depression found in past studies. Nearly 4 percent of fathers also developed depression in the first year after a child's birth.

After the child's first year, however, rates of new depression cases decreased sharply, according to the researchers, led by Dr. Irwin Nazareth of the University College London.

Among mothers, the incidence of depression dropped to 6 percent in the child's second year, then dipped somewhat as the child grew older. Among fathers, the incidence hovered between 2 percent and 3 percent per year after the child's first birthday.

The findings are important, in part, because they confirm that mothers do show an increased risk of depression in their baby's first year, said Dr. James F. Paulson, of Eastern Virginia Medical School in Norfolk, who was not involved in the study.

While postpartum depression is now widely recognized, there has been some debate about whether women actually are more likely to develop depression soon after giving birth than they are at any other time, said Paulson, who has studied depression in both new mothers and fathers.

These findings, he told Reuters Health, show loud and clear that mothers, as well as fathers, are more likely to be diagnosed with depression in their child's first year compared with other times.

The inclusion of fathers in the study is also important, according to Paulson. The risk, he said, is not as large as it is with mothers, but it is still substantial.

Some research has focused on the potential role of hormonal changes in mothers' postpartum depression. But, Paulson said, recent studies have been suggesting that psychosocial factors -- like stress, work demands, feeling a lack of support and adjusting to changes in lifestyle and relationships -- may be key in women's risk of developing postpartum depression.

Those same factors could also certainly be affecting fathers, he noted.

In this study, certain parents were more likely than others to develop depression at some point after their child was born -- including, not surprisingly, those who had suffered depression in the past.

A higher risk was also seen among parents who were between the ages of 15 and 24 when their child was born, compared with older parents. And parents living in the lowest-income areas faced higher risks than those in the most-advantaged areas.

Nazareth's team acknowledges that the study has limitations -- including its reliance on medical records from general practitioners. It is not clear whether all parents diagnosed with depression or given an antidepressant actually had clinical depression based on diagnostic criteria used by mental health professionals.

Still, the findings point to a need for appropriate recognition and management of parental depression in primary care, the researchers conclude.

Paulson suggested that parents, particularly new parents, talk with their doctor if they develop symptoms such as persistent sadness or an inability to take pleasure in activities they once enjoyed.

The so-called baby blues are common among new moms, but that refers to feelings -- including sadness, irritability and anxiety -- that usually fade on their own within days to a week of the baby's birth.

According to Paulson, parents with lasting symptoms that are interfering with their daily life should talk to their doctor, who can refer them to a mental health professional. Treatment options for depression include talk therapy and antidepressant medication; there are also support groups for parents with postpartum depression, which can be helpful in dealing with symptoms.