Researchers at the Centre for Health Equity Studies in Stockholm (CHESS) have discovered that depression can increase the risk of premature birth when experienced in both mothers and fathers. While depression in women during pregnancy has long been known to have detrimental effects on babies, such as low birth weight and increased risk of premature birth, little research has examined the impact of depression in fathers and its effect on the health of the mother or unborn child.

The team examined over 350,000 births in Sweden between the years 2007 and 2012 and examined parental depression in order to see if there was a link to premature birth between 22 and 31 weeks, as well as between 32 to 36 weeks.

For both the male and female groups, depression was defined as either being prescribed antidepressant medication or receiving hospital care from 12 months before conception all the way to the second trimester. Additionally, those who had no depression in the 12 months prior to their diagnosis were considered "new" cases, as opposed to the other cases which were grouped into the "recurrent" depression category.

The results found that mothers with both new and recurrent depression were connected to a 30 to 40 percent increased risk of premature birth between 22 to 21 weeks, but new depression in fathers was connected to a 38 percent increase in the risk of premature birth between 32 to 36 weeks. Conversely, recurrent depression in fathers showed no connection to premature birth.

"Depression of a partner can be considered to be a substantial source of stress for an expectant mother, and this may result in the increased risk of very preterm birth seen in our study," Anders Hjern, who participated in the research, said in a press release. "Paternal depression is also known to affect sperm quality, have epigenetic effects on the DNA of the baby, and can also affect placenta function. However, this risk seems to be reduced for recurrent paternal depression, indicating that perhaps treatment for the depression reduces the risk of preterm birth."

"Our results suggest that both maternal and paternal depression should be considered in preterm birth prevention strategies and both parents should be screened for mental health problems," he added. "Since men are less likely to seek professional help for any mental health problems, a proactive approach towards targeting the wellbeing of expectant fathers may be beneficial."

The findings were published in the Jan. 19 issue of BJOG: an International Journal of Obstetrics and Gynaecology.