Fathers-to-Be Go Through Hormonal Changes, Too
June 23, 2000 -- We've all heard about the hormonal changes women go through
during and after pregnancy that help them get ready for motherhood, but some
researchers are uncovering evidence that points to parallel hormonal changes in
fathers-to-be. The researchers theorize that these changes may help make these
men kinder and gentler ? in other words, more paternal.
Hints of what these powerful hormones are capable of have already been
detected in animals. Consider the male Siberian dwarf hamster. "He is such
an extraordinary dad that he midwives the delivery of his babies. He actually
pulls them out of the birth canal and opens their airway, cleans off their
membranes, and enjoys sharing the placenta with mom," evolutionary
endocrinologist Katherine Wynne-Edwards, PhD, tells WebMD.
While you may not see many human males displaying that kind of behavior,
Wynne-Edwards, a professor at Queen's University in Kingston, Ontario, believes
that hormonal changes in men may help them prepare for fatherhood in more
In her most recent study, she and her colleagues recruited 33 Canadian
couples and collected saliva samples from both partners from as early as 10
weeks into the pregnancy through one month after birth. In some cases, the
couple even gave samples during the actual delivery. Wynne-Edwards hopes that
hormonal changes the researchers found in the saliva may someday be found to be
linked to behavioral changes. She presented her findings at the recent annual
meeting of the Endocrine Society in Toronto.
"We were interested in conducting the study because we know that in
animals, hormones influence maternal behavior," says Wynne-Edwards, noting
that research has also found hormonal influences on fatherly behavior in male
She says that what the researchers wanted to do first was test the
hypothesis that the fathers' hormones would change during their partners'
pregnancies. "And secondly, we have an expectation that if hormones change
in men, that they'll be a muted version of [what] females are using to turn on
maternal behavior," she says.
When Wynne-Edwards compared the hormone levels of the fathers-to-be with a
group of nonfathers, she found that the expectant dads had higher levels of
estradiol (a female hormone), lower testosterone levels, and lower levels of
the stress hormone cortisol. But she also found that both testosterone and
cortisol levels were elevated just before the birth and suppressed immediately
What all this means is not exactly clear, Wynne-Edwards says. "What we
are talking about are probably subtle modulations that occur at this absolutely
critically biological time in a man's life that make it -- we would guess, and
it is just a guess at this point -- easier for him to make the transformation
into committed fatherhood," she says.
Wynne-Edwards' belief is backed up by what she and others have found in
earlier studies. "In other species, testosterone decreases are associated
with becoming parental -- being responsive to the babies' cues, bringing in
food, sitting with the babies, or carrying the babies -- and high testosterone
levels are associated with not being parental," Anne Storey, PhD, tells
WebMD. Storey, a professor at Memorial University in Newfoundland, Canada, has
worked with Wynne-Edwards in the past, but was not involved in this study.