"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," said Anders Hjern from Centre for Health Equity Studies in Stockholm, Sweden.
The findings were published in BJOG: an International Journal of Obstetrics and Gynaecology.
"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," Hjern explained.
"Paternal depression is also known to affect sperm quality, have epigenetic effects on the DNA of the baby, and can also affect placenta function," Hjern noted.
In this study, more than 350,000 births in Sweden between 2007 and 2012 were investigated for parental depression and incidences of either very preterm birth (between 22 and 31 weeks) or moderately preterm birth (32-36 weeks).
For both men and women, depression was defined as having had a prescription of antidepressant medication, or receiving outpatient/inpatient hospital care, from 12 months before conception to the end of the second trimester of pregnancy.
Those who did not suffer from depression prior to this period were regarded as new cases, all other cases were defined as 'recurrent' depression.
While both new and recurrent depression in the mothers was associated with an increased risk of moderately preterm birth of around 30-40 percent, new depression in the fathers was associated with a 38 percent increased risk of very preterm birth.
Recurrent depression in the fathers was not associated with preterm birth at all.
"This risk seems to be reduced for recurrent paternal depression, indicating that perhaps treatment for the depression reduces the risk of preterm birth," Hjern explained.
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