Caregiving fathers: do hormones help them along?

First-time fathers stand at the doorstep of a new unfamiliar phase in their
lives - a phase with new responsibilities and challenges. Today*s fathers are
expected, socially and politically, to participate in the care and upbringing
of their offspring. However, fathers show different qualities and interests in
caregiving behavior.

This proposal centers on hormone-behavior dynamics in paternal caregiving, with
the goal of gaining a better understanding of the development of human paternal
caregiving. There is limited information on the hormonal basis of caregiving
patterns in humans. While there have been some studies of caregiving in women,
there have been virtually none involving men. The studies that have been
conducted have not related the hormonal changes that occur during the
transition into fatherhood to behavioral aspects of paternal caregiving
behavior. The scarce studies thus far leave the cause-effect relation between
hormones and care unanswered.

This longitudinal study consists of a Prenatal Study and a Postpartum study:
The aim of the Prenatal Study, performed around 32 weeks of gestation for the
fathers-to-be. The participants will be invited for laboratory visits, and
asked to collect biological material (i.e., saliva samples for testosterone and
cortisol assessments, and urine samples for vasopressin and oxytocin; bloodspot
samples for measuring prolactin will be taken at the lab) and fill in online
questionnaires at home (i.e. demographic information, health, personality, sex
role, caregiving attitudes, interest, and behavior, work hours).

During the experiment at our laboratory the participants will receive a single
dose intranasal oxytocin, vasopressin, and placebo in a double-blind,
intra-subject, counterbalanced crossover design. Because the oxytocin and
vasopressin may cause possible receptor sensitization effects the experiment
will be carried out once a week for a three week research period.
The first-time fathers will continue their participation in the Postpartum
Study. When the infants are 3, 6 and 9 months of age both parents will fill in
a 4-day diary about parental caregiving activities, and the father will answer
a questionnaire on the mother-father distribution of caregiving activities over
the last 3 months. During the diary periods fathers will also be requested to
collect biological samples to investigate whether for example variations in
quantity of care covary with oxytocin16.
Finally at 9 months postpartum fathers will be invited to visit the laboratory
together with their infant. This laboratory visit consists of two parts:
(1) Filling in questionnaires (i.e. caregiving attitudes, interest, and
behavior, parenting hassles, work hours).
(2) Videotaped observation of father-infant dyad during three activities at the
BSI lab: a diaper changing, a short semi-structured playing, and a feeding.

The participants visit our lab three times during the first part of the study.
Each time we will collect hormones mainly through non-invasive methods, i.e.
saliva and urine. Only prolactin is collected by a finger prick which is
considered as a relatively mild invasive method. The lab visits are regarded as
pleasant and interesting experiences by most participants (personal
communication during pilot study). A set of questionnaires are filled in
online, time approximately: 30 to 45 minutes.
During the second longitudinal part, the postpartum study, we chose to collect
only the minimal necessary data. Therefore we will ask the fathers to collect
hormones every 3 months using only the non-invasive methods, i.e. saliva and
urine. In addition, they will fill out a very basic caregiving diary during 4
days. When the infant is 9 months old the fathers are invited to come with the
child to the lab for a semi-structured observation including a diaper change, a
small feeding session and a play moment.
We are well aware of the time investment of the subjects and during the whole
study will take utmost care to accommodate their time schedules and wishes in
order to minimize their discomfort and strain.
The medical risks that could be related to the use of the intranasal sprays,
Syntocinon and Desmopressin, are considered very low for the following reasons:
(1) Only healthy subjects will participate. The candidates will be screened by
means of a health questionnaire. Subjects will be rejected upon indications of
health problems, e.g. psychotic symptoms, substance dependence, epilepsy,
severe kidney disease, and traumatic brain injury.
(2) The participants will receive each intranasal spray separated by at least
one week in order to give sufficient wash-out time to avoid any pharmacokinetic
carry-over effect.
(3) The hormonal sprays are synthetic substitutes of normal body hormones. By
administrating the intranasal sprays we alter the levels of these hormones for
a relatively short period. The hormone levels will reach their peak around 80
minutes after administration6,40 and decline rather rapidly afterwards40.
(4) The intranasal sprays are normally prescribed to vulnerable populations,
for example Syntocinon is used to induce milk production in breastfeeding
women, and Desmopressin is prescribed mainly for children with bedwetting
problems.
(5) The sprays have been extensively tested in clinical trials and the adverse
events as mentioned in the product information are relatively infrequent and
mild. Moreover, normally adverse events occur only after repeated use, which is
not the case in our study. In the VIS study participants will only receive a
single dose of each spray on one separate occasion.
(6) Similar intranasal sprays have been used without problem in scientific
studies in recent years, for example:
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Conference, Dresden, 17-20 July