The health of both mom and dad are key to a healthy pregnancy and birth, new research finds.
In the study of nearly 786,000 births, researchers found that dads who weren't in the best of health were more likely to have preterm and low birth weight infants who spent time in the neonatal intensive care unit (NICU).
"The study suggests that a father's health before conception should be considered, as it can affect the outcome of the pregnancy for both the child and mother," said lead researcher Dr. Alex Kasman. He's a resident physician in the department of urology at Stanford University Hospital in Stanford, Calif.
Because the study looked at data retrospectively, it can't prove that the father's health caused these medical problems, only that they seem to be associated.
Specifically, fathers with conditions such as high blood pressure, obesity, diabetes, cancer or depression had 19% higher odds of having a preterm infant, 23% higher odds of having a low birth weight infant and 28% higher odds of having an infant who needed a stay in the NICU, the researchers found.
Also, the women whose partners were in poor health were more likely to have pregnancy complications, such as gestational diabetes or preeclampsia, the findings showed.
It's not known exactly how a father's health contributes to the health of a newborn, but Kasman speculated that several factors might be at play.
"A father contributes half the genome and health can impact expression of genes, so it is reasonable to hypothesize that conditions that make a father healthy, or not, may impact these genes," he said.
Also, a father's health may have negative effects on the health of the placenta, which can lead to changes in the baby's outcome, Kasman noted.
Evidence in previous studies found poor health can negatively affect the quality of sperm in the same way as environmental exposures to smoking and toxins do, he added.
It's also possible that genetics may be a factor, but that's not certain, Kasman said.