The researchers noted that fathers had high levels of the stress hormone cortisol in their saliva prior to the discharge of babies.
The stress levels are particularly more pronounced with medically vulnerable babies leaving the NICU and going home.
"While finally bringing a baby home is really wonderful, it can also be stressful because of sleep deprivation, the lack of control and having to respond constantly to the baby's needs," said Craig Garfield, Associate Professor at the Northwestern University in Evanston, the US.
"Father goes from a situation where the baby and mother are cared for by experts in the hospital to having to simultaneously care for his baby, partner and work. He is supposed to be the 'rock' for his partner but the stress can really set in."
An increased level of stress might also impact the parenting of the child and alter the level of attachment between the babies and their parents.
The study, published in the journal of Perinatal and Neonatal Nursing, measured the parents' stress levels in two ways -- salivary tests and surveys.
They tested the participants initially the day before they were discharged from the hospital, then one day, five days and 14 days after coming home.
To help relieve fathers' stress and ease the transition, more emphasis should be made for the father to become comfortable and gain confidence with the baby while still in the NICU. Mothers need to remember that fathers too need time to relax, Garfield said.
"Babies thrive when parents thrive, and if parents are stressed out, that can impact their parenting of the child, the relationship between the mother and father can alter infant attachment," Garfield said.