Current Studies

Maternal Mental Health and Oxytocin Levels in Pregnant and Postpartum Women (longitudinal study)

Principal Investigator: Dr. P. Zelkowitz

Co-Investigators: Nancy Feeley, N., Ph.D., Ian Gold, Ph.D., Barbara Hayton, M.D., C. Sue Carter, Ph.D.

Funding: CIHR

Background: Mental health problems during pregnancy and the postpartum period affect a large number of women. Studies of depression during pregnancy and postpartum have reported prevalence rates of 12-14%, while anxiety has been reported in 15-16% of pregnant women, and in 8-9% of postpartum women. There is accumulating evidence of the adverse effects of prenatal anxiety and depression on fetal development, obstetrical complications, pregnancy outcomes such as low birth weight, and subsequent child development. Risk factors for prenatal and postpartum depression include stressful life events, lack of support as well as a past history of anxiety and depression. While research that links hormonal changes to depression is lacking, the hormone oxytocin is of particular interest for its known role in the birth experience (labour and delivery) as well as in social behavior.

Purpose: The purpose of this study is to examine mood during the perinatal period within an integrated biological, psychological, and sociocultural model that could link adverse life circumstances as well as hormonal and physiological risk factors to maternal mental health problems. We examine the relationship of endogenous oxytocin levels to maternal symptoms of depression, anxiety, post-traumatic stress and delusions during pregnancy and postpartum. In addition, we examine the extent to which oxytocin levels mediate the relationship between maternal mood and mother-infant interaction in early infancy.

Design: 341 women were enrolled across two birthing sites: The Montreal Jewish General Hospital (n=244) and the Cote-Des-Neiges Birthing Center of Montreal (n=97). All participants were asked to complete questionnaires or tasks that assessed depression, worry, anxiety, sleep trends, body pain, family support, delusion, trust, attachment and post-traumatic stress. Each participant also provided a 10 mL blood sample in order to measure endogenous oxytocin levels. Women were seen twice prenatally and once postpartum.

Results: This study was completed in September of 2011. Data analyses are currently underway.

PTSD Symptoms in At-Risk Mothers 5, 8 and 26 weeks After Childbirth

Principal Investigator: Nancy Feeley, N. Ph.D.

Co-Investigators: Phyllis Zelkowitz, Ed.D., Ian Gold, Ph.D., Barbara Hayton, M.D., Apostolos Papageorgiou, M.D., Togas Tulandi, M.D., Francine Lefebrve, M.D.

Funding: CIHR

Background: Evidence from a systematic review indicates that many women develop PTSD after childbirth, with reported prevalence rates of 2.8 to 5.6% at 6 weeks postpartum and 1.5% at 6 months postpartum. Understanding the course of symptoms after childbirth would provide valuable information for the identification and treatment of women, however little is known about the time course of symptoms. Posttraumatic stress and depression can co-occur in the postpartum period but co-morbidity has not been frequently studied. Studies are needed investigating the relationship between PTSD symptoms and maternal interactive behavior. Mothers of low birthweight infants requiring Neonatal Intensive Care Unit (NICU) hospitalization following birth, and women who have an emergency caesarean birth are at greater risk for developing PTSD. These two at-risk groups were the focus of this study.

Purpose: The study purpose was to examine the pattern of PTSD symptoms over time, and the relationship between PTSD symptoms and maternal interactive behavior in four groups of postpartum women: Two groups of women at-risk (mothers of NICU infants and those having an emergency caesarean birth) and two groups not at-risk (women having a vaginal birth and those who had an planned caesarean birth).

Design: In a comparative prospective cohort study, 298 women responded to a self-report questionnaire about PTSD symptoms at 5 weeks’ post childbirth. At 8 and 26 weeks after childbirth, research staff visited women in their home. The women completed self-report questionnaires assessing both PTSD and depressive symptoms. At the end of the 26-week home visit, women were also videotaped interacting with their infant.

Results: At 5 and 8 weeks, women whose low birthweight infant required NICU hospitalization reported significantly more PTSD symptoms than all other groups. At 26 weeks, they continued to report greater PTSD symptoms than women who had a vaginal birth and women who had planned caesarean birth. Women who had an emergency cesarean birth (threat to their life or their infant’s) had greater PTSD symptoms compared to women having a vaginal birth without forceps or vacuum only at 26 weeks.

For all groups, PTSD symptoms decreased significantly from 5 to 8, and 8 to 26 weeks; and there was no difference between groups in the decline across these time periods. Only the planned cesarean birth group’s symptoms decreased significantly between 5 to 8 weeks. However, from 8 to 26 weeks there was a significant decrease for vaginal birth and NICU women.

Correlational analysis revealed no significant associations between maternal PTSD symptoms at 5, 8 or 26 weeks, and mother, infant and overall dyadic interactive behavior. However, women with elevated PTSD symptoms at 26 weeks were significantly more intrusive in interactions with their infants.

Conclusion: Although the PTSD symptoms of women who have an infant born low birthweight requiring NICU hospitalization decreased from 8 to 26 weeks after childbirth, they continue to report greater PTSD symptoms than low-risk mothers. Clinical guidelines in the USA now recommend screening NICU mothers for PTSD symptoms. Studies with longer term follow up after birth are needed to determine how long their symptoms persist. Women who have an elevated level of PTSD symptoms, regardless of group, were more intrusive in interactions with their infants, and the effects on their infants warrants investigation.

Effects of naturally enhanced oxytocin levels on trust

Principal investigator: Ian Gold, Ph.D.

Co-Investigators: Phyllis Zelkowitz, Ed.D.; Nancy Feeley, N., Ph.D.; Barbara Hayton, M.D.; C. Sue Carter, Ph.D., Togas Tulandi, M.D., Marie Prévost, Ph.D.

Funding: SSHRC

Background: The hormone oxytocin seems to influence social behaviours. Research has shown that this hormone is associated with trusting behaviours and with our ability to understand what others think or feel. This project seeks to better understand how oxytocin functions in these types of social contexts in a population that has naturally varying oxytocin levels: breastfeeding women.

Purpose: The goal of this study is to explore the relationship between oxytocin levels, a variant of the oxytocin receptor gene, the understanding of others’ mental states, and judging trustworthiness. Knowing that mothers naturally produce oxytocin when they breastfeed, we will evaluate the relationship between oxytocin, the understanding of others’ mental states and trust feelings at two different intervals after breastfeeding. These two sessions represent two periods of time where circulating oxytocin levels are different. We hope to observe different behaviours between the two sessions, if oxytocin levels indeed vary from one session to the other.

Design: The 50 mothers recruited at the Jewish General Hospital answered various questionnaires on trust, attachment, delusional ideas, paranoia, and their labour. At each of the 2 home visits (with a 2 week interval between each visit), mothers completed two tasks evaluating their understanding of others’ mental states (Reading the Mind in the Eyes) and their judgment of strangers’ trustworthiness, at two different time intervals after breastfeeding. At each visit, the mothers gave saliva samples just before starting the test in order to measure their levels of circulating oxytocin as well as to verify which variant of the oxytocin receptor gene they carry.

Results: Data collection is complete. We are currently analyzing the results of this study.

Hormonal, genetic, and psychosocial factors in the developing parent-child relationship: A follow up study of parents and their toddlers (longitudinal study)

Principal investigator: Dr. P. Zelkowitz

Co-Investigators: Ian Gold, Ph.D., Nancy Feeley, N., Ph.D., Barbara Hayton, M.D., Gustavo Turecki M.D., Ph.D., Jennifer Bartz Ph.D, Lawrence Joseph Ph.D, & Ellen Moss Ph.D.

Funding: CIHR

Background: Prevalence rates of depression and anxiety in women during the perinatal period suggest mental health problems during the life event of childbearing may be common. Both mental health problems and their risk factors are increasingly being shown to have lasting effects on the development of the child and of parent-child relationships. The hormone oxytocin has been linked to social behaviors and birth experience (including labour and delivery), and more recently has been linked to postpartum mood and maternal behaviors. Given the important hormonal changes that occur throughout pregnancy and childbirth, it is important to investigate how these changes may be related to mood and developmental outcomes.

Purpose: This study is a 2.5 year follow-up of a longitudinal study examining perinatal mood and hormonal and physiological risk factors. We are now examining how both current and perinatal endogenous oxytocin and DNA may be related to different aspects of development, including mother-toddler interactions and maternal mood.

Design: We are following up with the 341 women from the original PMH study. So far, over 200 women have participated in visits assessing mood, anxiety, attachment, interactive behavior, and the ability to understand other people’s state of mind. Mothers have been providing blood samples to measure endogenous oxytocin, and both mothers and their toddlers have been providing saliva samples to look at DNA.

Results: This study and its data analyses are still underway. Participant recruitment was completed in September 2014.

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