It’s no surprise that both the emotional and physical health of an expectant mother carries huge ripples for their child, especially during pregnancy.

New research released Wednesday, however, suggests that the mental wellbeing of fathers-to-be also has a large impact on the immediate health of their child. The study, published in BJOG: An International Journal of Obstetrics and Gynaecology, studied the medical records and parental histories of more than 350,000 births in Sweden, and found that a history of depression in either the mother or father during pregnancy was associated with a greater risk of premature birth. These infants are, in turn, more at risk for a large number of ailments or disadvantages later on in life.

"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 senior study author Dr. Anders Hjern, of the Centre for Health Equity Studies in Stockholm, Sweden, in a statement. "Since men are less likely to seek professional help for any mental health problems, a proactive approach toward targeting the wellbeing of expectant fathers may be beneficial."

Hjern and his colleagues considered parents to be depressed if they had either received a prescription for antidepressant medication or sought out hospital care from the 12 months before conception up to the second trimester. They also made sure to note whether a depressed parent had earlier episodes of depression.

Specifically, depressed mothers were associated with a 30 to 40 percent increased risk of having their baby slightly ahead of schedule (32 to 36 weeks), regardless of whether this was their first bout with depression. For fathers, that risk was more nuanced, with only those who were recently diagnosed for the first time being associated with premature birth. For these families, having a newly depressed dad upped the risk of a premature birth between 22 and 31 weeks by 38 percent.

"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," speculated Hjern. "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."

Though more research will need to be done to better tease out the exact influence(s) that paternal depression has on a growing fetus’s health, other experts are not shy about the study’s implications.

"We encourage anyone, and particularly those planning a family or who are pregnant, and are experiencing a change in mood, irritability, or anxiety to seek advice," commented Dr. Patrick O'Brien, obstetrician and spokesman for the UK’s Royal College of Obstetricians and Gynaecologists (RCOG). "No one should suffer in silence — there is help and support available."

Source: Liu C, Cnattingius S, Bergström M, et al. Prenatal parental depression and preterm birth: A national cohort study. BCOG. 2016.