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Mental Disorders Among Mothers of
Children Born Preterm: A Population-Based
Cohort Study in Canada
Troubles mentaux chez les femmes d’enfants prématurés : une
étude de cohorte dans la population au Canada
Deepak Louis, MD, DM
1
, Hammam Akil, MD
1
, James M. Bolton, MD
2,3
,
Fabiana Bacchini, MSc
4
,KarenNetzel
5
, Sapna Oberoi, MD, DM
6
,
Christy Pylypjuk, MD
7
, Lisa Flaten, MSc
3
, Kristene Cheung, PhD
8
,
Lisa M. Lix, PhD
3,9
,ChelseaRuth,MD
1,3
, and Allan Garland, MD, MA
3,10
Abstract
Background: Our aim was to examine the association between preterm delivery and incident maternal mental disorders
using a population-based cohort of mothers in Canada.
Methods: Retrospective matched cohort study using Manitoba Centre for Health Policy (MCHP) administrative data in
Manitoba. Mothers who delivered preterm babies (<37 weeks gestational age) between 1998 and 2013 were matched 1:5
to mothers of term babies using socio-demographic variables. Primary outcome was any incident mental disorder within 5
years of delivery defined as any of (a) mood and anxiety disorders, (b) psychotic disorders, (c) substance use disorders,
and (d) suicide or suicide attempts. Multivariable Poisson regression model was used to estimate the 5-year adjusted incidence
rate ratios (IRRs).
Results: Mothers of preterm children (N=5,361) had similar incidence rates of any mental disorder (17.4% vs. 16.6%, IRR
=0.99, 95% CI, 0.91 to 1.07) compared to mothers of term children (N=24,932). Mothers of term children had a higher
rate of any mental disorder in the first year while mothers of preterm children had higher rates from 2 to 5 years. Being the
mother of a child born <28 week (IRR =1.5, 95% CI, 1.14 to 2.04), but not 28–33 weeks (IRR =1.03, 95% CI, 0.86 to 1.19)
or 34–36 weeks (IRR =0.96, 95% CI, 0.88 to 1.05), was associated with any mental disorder.
Interpretation: Mothers of preterm and term children had similar rates of incident mental disorders within 5-years post-
delivery. Extreme prematurity was a risk factor for any mental disorder. Targeted screening and support of this latter group
may be beneficial.
1
Section of Neonatology, Department of Pediatrics and Child Health, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
2
Department of Psychiatry, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
3
Manitoba Centre for Health Policy, University of Manitoba, Winnipeg, Canada
4
Canadian Premature Babies Foundation, Toronto, Canada
5
Neonatal Intensive Care Unit, Women’s Hospital, Winnipeg, Canada
6
Department of Pediatric Hematology Oncology, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
7
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
8
Department of Clinical Health Psychology, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
9
Department of Community Health Sciences, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
10
Department of Medicine, Rady Faculty of Medicine, University of Manitoba, Winnipeg, Canada
Corresponding author:
Deepak Louis, MD, DM, Department of Pediatrics and Child Health, University of Manitoba, WN-2064, 820 Sherbrook Street, Winnipeg, Manitoba, Canada
R3A 1R9.
Email: dlouis@hsc.mb.ca
Original Research
The Canadian Journal of Psychiatry /
La Revue Canadienne de Psychiatrie
1‐9
© The Author(s) 2022
Article reuse guidelines:
sagepub.com/journals-permissions
DOI: 10.1177/07067437221138237
TheCJP.ca | LaRCP.ca
Abrégé
Contexte : Notre objectif était d’examiner l’association entre l’accouchement avant terme et les troubles mentaux mater-
nels incidents à l’aide d’une cohorte de mères dans la population au Canada.
Méthodes : Une étude de cohorte appariée rétrospective a utilisé les données administratives du Centre d’élaboration de la
politique des soins de santé du Manitoba (MCHP). Les mères qui ont accouché de bébés avant terme (< 37 semaines d’âge
gestationnel) entre 1998 et 2013 ont été appariées à raison d’une sur 5 à des mères de bébés à terme à l’aide de variables
sociodémographiques. Le résultat principal était tout trouble mental incident dans les 5 ans après l’accouchement, défini
comme étant l’un (a) des troubles anxieux ou de l’humeur (b) des troubles psychotiques, (c) des troubles liés aux substances,
et (d) des suicides ou tentatives de suicide. Le modèle de régression multi-variable de Poisson a servi à estimer un ratio du
taux d’incidence (RTI).
Résultats : Les mères d’enfants prématurés (N =5 361) avaient des taux d’incidence semblables de tout trouble mental
[17,4% c. 16,.6%, RTI =0,99, IC à 95% 0,91 à 1,07)] comparé aux mères d’enfants à terme (N =24 932). Les mères d’en-
fants à terme avaient un taux plus élevé de tout trouble mental dans la première année alors que les mères de prématurés
avaient des taux plus élevés de 2 à 5 ans. Être mère d’un enfant né avant < 28 semaines (RTI =1,5, IC à 95% 1,14 à 2,04]),
mais pas à 28–33 semaines (RTI =1,03, IC à 95% 0,86 à 1,19]) ou à 34–36 semaines (RTI =0,96, IC à 95% 0,88 à 1,05]),
était associé à tout trouble mental.
Interprétation : Les mères d’enfants prématurés et nés à terme avaient des taux semblables de troubles mentaux incidents
dans les 5 ans suivant l’accouchement. La prématurité extrême était un facteur de risque pour tout trouble mental. Le
dépistage ciblé et le soutien de ce dernier groupe peuvent être bénéfiques.
Keywords
maternal health, depressive disorders, anxiety, substance use disorders, postpartum, prematurity
Introduction
Approximately 8% of all live births in Canada are preterm
(<37 weeks), contributing to 30,000 births,
1
and costing
eight billion dollars to the Canadian health care system annu-
ally.
2
Children born preterm can have multiple short-term
and long-term morbidities. Long-term morbidities include
neurosensory impairments (cerebral palsy, vision and
hearing deficits), behavioural and developmental challenges,
cognitive delays and learning disorders.
3–7
Parenting a child born preterm therefore can be stressful
for mothers making them prone to mental disorders.
8
Previous studies exploring the association between prematu-
rity and maternal mental disorders were limited by small
sample sizes, residual confounding, selection and attrition
biases,
9,10
and the use of self-report questionnaires for diag-
nosing mental disorders.
11–13
Our aim was to study the asso-
ciation between prematurity and incident mental disorders
using a population-based cohort of mothers.
Methods
This retrospective cohort study used the Population Research
Data Repository at the Manitoba Centre for Health Policy
(MCHP), University of Manitoba, Canada.
14
The
Repository contains linked education, social, health and
justice data collected by government and healthcare provid-
ers for all Manitoba residents. Validated maternal-child link-
ages between the datasets were used to build the study
cohort.
15,16
These data have almost complete population
coverage for Manitoba, which has a publicly funded, single
payer healthcare system. Study approvals were obtained
from the Research Ethics Board and other data custodians.
eTable 1 lists the datasets and corresponding variables used
in the study.
All women who delivered liveborn singleton or twin
babies in Manitoba between 1998 and 2013 formed the
study population. From them, we included mothers who
had delivered preterm babies (<37 weeks gestational age)
(a) who were continuously registered with Manitoba Health
at least 5 years before and 5 years after the index birth
event, and (b) whose children were continuously registered
with Manitoba Health for 5 years after the index birth
event. For mothers with more than one preterm delivery,
only the first preterm birth was included as long as the sub-
sequent one occurred > 5 years later.
We excluded preterm mothers: (a) who had pre-existing
mental disorders (i.e., within the 5 years prior to the index
birth event), (b) whose children died within 5 years of the
index delivery or (c) for whom we could not find term
mothers as matches.
We used two different definitions for mental disorders
in the study, one to exclude mothers with pre-existing
mental disorders, and the other to identify incident
mental disorders among the included mothers. For the
former, we used validated administrative data definitions
available in the Repository based on outpatient physician
diagnoses using ICD codes, medication prescriptions and
hospital admissions for mental health with high sensitivity
to avoid false-negative classification of mental disorders
2The Canadian Journal of Psychiatry
(eTable 2) and applied them to a 5-year blackout period
prior to the index birth event.
17,18
For mothers who delivered term babies, we used the same
inclusion and exclusion criteria as for preterm mothers except
that preterm birth was replaced by term birth (≥37 weeks
gestational age). Unlike mothers of preterm babies, mothers
who had more than one term baby during the 5-year period
were included.
For each mother of preterm child, we sought five matched
mothers of term children based on the following criteria at the
time of the index birth event: (a) year of delivery (±3 years),
(b) singleton versus twin birth, (c) maternal age (±1 year), (d)
SEFI-2 score (±0.3 standard deviation),
19
(e) sex of the child,
(f) parity of the mother (1 vs. >1), (g) marital status (married/
common law vs. single), and (h) rural vs. urban residence.
20
For mothers of preterm children with less than five
matches, matching with replacement was performed; specifi-
cally, the same term birth event was allowed to be matched to
more than one preterm birth event from separate mothers, and
a given mother’s separate term birth events could also be
used as a match for separate preterm birth events. For those
preterm mothers who did not have five matches, frequency
weighting was used during the analysis. The statistical
power and efficiency of matched cohort studies plateau
beyond a matching ratio of 1: 4 to 1:5 as per literature
21
and it also becomes challenging to find the appropriate
number of matches.
Outcome
Our primary outcome was any de novo mental disorder
among mothers within the 5 years of the index birth event.
Any mental disorder included any one or more of the follow-
ing: (a) mood and anxiety disorders, (b) psychotic disorders,
(c) substance use disorders including alcohol use disorders,
and (d) suicide or suicide attempts. To identify mothers
with new mental disorders, we used administrative data def-
initions based on outpatient physician diagnoses using ICD
codes, medication prescriptions, and hospital admissions
for mental health with the highest agreement (kappa value)
to clinical diagnoses so as to avoid both false-positive and
false-negative diagnoses (eTable 2).
17,18
Secondary outcomes included each mental disorder
separately, and the time to diagnosis of any mental disor-
der, the latter definedbythefirst date of hospitalization
or physician visit or prescription filled for any of the
mental disorders.
Covariates
These included mother’s age at index delivery, year of deliv-
ery, residence, maternal diabetes (gestational or pre-existing),
maternal hypertension (gestational or pre-existing), smoking,
income assistance at delivery, SEFI-2 score, marital status,
birth order, Caesarean delivery, infant’s sex, small for
gestational age,
22
and singleton versus twins. These variables
were identified from previous literature.
12,23–26
Statistical and Sensitivity Analysis
The unit of analysis was the index birth event. Descriptive
statistics were used for baseline variables. Standardized
mean differences were calculated to compare them, with
values >0.1 considered substantial.
27
To test the association
between preterm birth and maternal mental disorders
(primary analysis), matched preterm and term birth events
along with the covariates were entered into multivariable
Poisson regression models. We fit two models to the data:
(i) prematurity defined as <37 weeks gestational age, and
(ii) prematurity categorized as <28 weeks, 28–33 weeks,
and 34–36 weeks. We assessed multicollinearity among
covariates using the variance inflation factor (VIF); all VIF
were <4.
28
Since prematurity was our primary exposure var-
iable, we adjusted the P-values for the four prematurity var-
iables mentioned above across the two models using Sime’s
false discovery rate step-up method
29,30
while all other
P-values remain unadjusted for multiple comparisons. As
all subjects had the same 5-year follow-up period, the expo-
nentiated coefficient of the primary exposure variable repre-
sented the 5-year incidence rate ratio (IRR).
A sensitivity analysis was planned a priori, including
mothers whose children died within 5 years of the index
birth event. Statistical analyses were conducted using SAS
9.4 (SAS Institute Inc., Cary, NC, USA).
Results
Of the 14,362 women who had preterm babies during the
study period, 5,361 were eligible and included in the study
cohort (Figure 1). Among the 169,192 term mothers,
94,497 were eligible and 24,932 were matched to mothers
of preterm children. Most (87%) preterm mothers had five
matches, 2.7% had four, 2.6% had three, 4.3% had two,
and 3.6% had one match. The groups were similar except
for mother’s age at index delivery and first child birth, prev-
alence of diabetes, hypertension, and delivery by Caesarean
section, all of which were higher among mothers of
preterm children (Table 1).
Primary and secondary outcomes of the cohort with pre-
maturity defined as <37 weeks are shown in Table 2. There
were no differences in the outcomes between preterm
mothers and term mothers. Mothers of extremely preterm
babies (<28 weeks) had higher incidence rates of any
mental disorder, mood and anxiety disorders, and substance
use disorders compared to mothers of other preterm groups
(28–33 weeks and 34–36 weeks) and term children (Table 3).
eTable 3 shows the regression model based on gestational
age categories. We found that compared to mothers of term
children, being a mother of <28 week infant was associated
with developing any mental disorder, while mothers of
La Revue Canadienne de Psychiatrie 0(0) 3
infants born at 28–33 weeks and 34–36 weeks gestational age
were not.
Sensitivity analysis including mothers whose children
died within 5 years after birth identified two additional
mothers in the preterm group and eight in the term group;
the results were similar to the primary cohort (eTable 4).
The time of diagnosis of any mental disorder is shown in
Figure 2. In the first year after the index delivery, term mothers
had a higher incidence for any mental disorder compared to
preterm mothers. After the first year, preterm mothers had a
higher rate for mental disorders compared to term mothers.
Discussion
In this population-based matched cohort study, the incidence
rate of mental disorders did not differ between mothers of
preterm and term children when preterm group was analyzed
as a single category. However, we found an association
between mothers of extremely preterm infants (<28 weeks)
and the incidence rate of any mental disorder. A majority
of mothers of preterm children were diagnosed with mental
disorders beyond the first year after delivery while for
mothers of term children, a plurality was diagnosed within
the first year after delivery.
Preterm delivery and subsequent care of children born
preterm can be stressful for parents, especially mothers,
adversely affecting their mental health. Maternal mental
health strongly impacts the entire family. Beyond
their own physical health and well-being,
31–33
maternal
mental disorders can adversely affect their partners’
mental health,
34,35
and their infants’socio-emotional and
behavioral development.
36,37
The latter is particularly rel-
evant for preterm infants, who have a higher baseline
risk for developmental impairment compared to term
infants.
38,39
Our study improved on the methodologies of previous
population-based studies.
23–25,34,40–42
This included
using a matched cohort allowing us to account for multiple
confounders, the use of a more stringent 5-year blackout
period to exclude mothers with pre-existing mental disor-
ders, excluding mothers with any pre-existing mental dis-
order rather than a specific mental disorder, and using a
composite of any mental disorder as our primary
outcome. In addition, while the postpartum follow-up
period of most studies was 1 year, our use of 5 years
more completely captured the long-lived maternal expo-
sure to stress following preterm delivery.
43,44
This
allowed the capture of a more precise and harmonious
sample, despite the exclusion of 63% of eligible mothers
who delivered preterm children.
Previous studies based on clinical interviews report the
prevalence of postpartum depression (PPD) to be 0.5–
Figure 1. Flow of study cohort.
4The Canadian Journal of Psychiatry
1.4%.
23–25
In contrast, we found a higher incidence of any
mental disorder (∼17%) among both mothers of preterm
and term children, with mood and anxiety disorders contrib-
uting the most (∼13%). Potential reasons for our high rates
include the longer duration of follow up (5 years vs. 1 year
in other studies), the use of a composite of mental disorders
as the outcome, and the relatively high prevalence of mental
disorders prevalent in Manitoba and Canada compared to
other high-income countries.
45
A 2018 report showed that
the 5-year prevalence of any mental disorder in Manitoba
among 18–24 and 25–44-year-old women was 36% and
42%, respectively.
18
Similarly, a national mental health
survey of Canadian mothers found a 23% prevalence of
PPD and anxiety.
46
Results of previous population-based studies evaluating
prematurity and mental disorders have been mixed, with
some showing preterm delivery as a risk factor for
PPD
24,25,40,41
while others did not find such an
effect.
23,34,42
Despite these differences, most of them evalu-
ated prematurity as a single category, that is, <37 weeks
gestational age.
25,41,42
In the only study that showed an asso-
ciation between degree of prematurity and PPD, Silverman
et al.
24
found that preterm birth born <32 weeks (OR: 1.53,
95% CI, 1.12 to 2.10), but not 32–36 weeks (OR: 1.07,
0.91–1.26), was associated with PPD. These findings were
similar to our results, except that we found mothers of
<28-week infants to be at an increased risk for any mental
disorder (IRR: 1.53, 1.14–2.04) while mothers of 28–33
weeks and 34–36 weeks infants were not. These findings
are not unexpected given the longer duration of hospital
stay of these extremely preterm infants and the higher rates
of short-term and long-term morbidities in them.
In addition to extreme prematurity, other risk factors for
mental disorders in our cohort included higher birth order,
maternal age <20 years, maternal diabetes, Caesarean deliv-
ery, receipt of income assistance, and mothers who were
single, all of which are congruent with previous literature.
47
Our findings highlight a vulnerable group of mothers who
may have fewer resources (both through internal coping
mechanisms as well as external support) to deal with the
Table 1. Baseline Characteristics of the Study Cohort.
Population cohort
Preterm mothers N=5361 Term mothers N=24932 Standardized mean difference
Maternal characteristics
Age at delivery (years), median [IQR]
mean ±SD
28 [24,33]
28.38 ±6.15
28 [23,32]
28.08 ±5.84 0.05
Age at first child birth (years), median [IQR]
mean ±SD
24.74 [19.72,29.63]
25.13 ±6.12
24.55 [19.86,29.21]
24.91 ±5.80 0.01
Rural residence 2859 (53.3%) 13214 (53.0%)
Birth order, median [IQR]
mean ±SD
2 [1,3]
2.11 ±1.47
2 [1,3]
2.11 ±1.46 0.00
Diabetes 424 (7.9%) 521 (2.1%)
Hypertension 924 (17.2%) 2117 (8.5%)
Smoking, N(%) 868 (16.2%) 3750 (15.0%)
Receipt of income assistance 526 (9.8%) 2426 (9.7%)
SEFI-2, median [IQR]
mean ±SD
0.08 [−0.49,0.94]
0.31 ±1.16
0.07 [−0.46,0.92]
0.32 ±1.14 0.00
Being married or in a common-law relationship 1971 (36.8%) 9116 (36.6%)
Caesarean section 1860 (34.7%) 5473 (22.0%)
Neonatal characteristics
Gestational age (weeks), median [IQR]
mean ±SD
35 [34,36]
34.43 ±2.3
39 [38,40]
39.29 ±1.3 −3.25
<28 weeks
28–33 weeks
34–36 weeks
133 (2.5%)
1002 (18.7%)
4226 (78.8%)
-
-
Birth weight (grams), median [IQR]
mean ±SD
2560 [2137,2938]
2529 ±696
3485 [3136,3840]
3490 ±530 −1.71
Male 2879 (53.7%) 13414 (53.8%)
5min Apgar score, median [IQR]
mean ±SD
9 [8,9]
8.47 ±1.02
9 [9,9]
8.89 ±0.62 −0.59
SGA 456 (8.5%) 2392 (9.6%)
Twins 878 (16.4%) 2843 (11.4%)
Care by child and family services 294 (5.5%) 989 (4.0%)
Values are N(%) unless otherwise indicated.
IQR =interquartile range; SD =standard deviation; CI =confidence intervals; SGA =small for gestational age; SEFI-2 =socioeconomic index
factor-version 2.
La Revue Canadienne de Psychiatrie 0(0) 5
challenges of having a preterm infant. However, these risk
factors should be considered hypothesis generating and
needs further exploration.
We also found that most mental disorders among preterm
mothers were diagnosed after the first postpartum year,
unlike term mothers where most were diagnosed in the first
year. The potential reasons for this finding include the singu-
lar focus of mothers on their preterm child after delivery and
sometimes mothers not realizing the changes occurring to
their mental health during this very stressful period. These
Table 3. Mental Disorders Based on Gestational age Categories Among Preterm Mothers.
<28 weeks N=133 28–33 weeks N=1002 34–36 weeks N=4226
Primary outcome
Any mental disorder 36 (27.1%) 189 (18.9%) 710 (16.8%)
Secondary outcomes
Mood and anxiety disorder 24 (18.1%) 157 (15.7%) 551 (13.0%)
Psychotic disorders <6 <6 17 (0.4%)
Substance use disorder 18 (13.5%) 53 (5.3%) 216 (5.1%)
Suicidal attempts or suicide <6 <6 15 (0.4%)
Values are N(%).
Table 2. Primary and Secondary Outcomes of the Cohort (Prematurity Defined as <37 Weeks).
Preterm cases N=5361 Term controls N=24932 Adjusted IRR (95% CI)
a,b
P-value
Primary outcome
Any mental disorder 935 (17.4%) 4142 (16.6%) 0.99 (0.91,1.07) 0.75
d
Secondary outcomes
Mood and anxiety disorder 732 (13.7%) 3335 (13.4%) 0.95 (0.86,1.04) 0.27
Psychotic disorders 19 (0.4%) 54 (0.2%) -
c
-
Substance use disorder 287 (5.4%) 1273 (5.1%) 1.02 (0.88,1.19) 0.76
Suicidal attempts or suicide 21 (0.4%) 41 (0.2%) -
c
-
Values are N(%).
IRR =incidence rate ratio; CI =confidence intervals.
a
Via Poisson regression.
b
Adjusted for maternal age, birth order, maternal diabetes, maternal hypertension, smoking, caesarean section, rural residence, SEFI-2 score, receipt of income
assistance, marital status, twin birth, sex, SGA, and the year of index delivery.
c
Due to small sample size in the psychotic disorders and suicide attempts or suicide group, the models did not converge for those outcomes.
d
Adjusted for multiple comparisons via Sime’s false discovery rate method.
Figure 2. Time to diagnoses of mental disorders among preterm and term mothers.
6The Canadian Journal of Psychiatry
mothers also receive support from the medical team includ-
ing social work and other parents initially whereas they
lose these supports after discharge from the hospital. The
emerging developmental issues in their child also might con-
tribute to their mental health challenges. Overall, the findings
of this study underscore the need for continued mental health
surveillance of mothers in the first few years after preterm
delivery.
Our study has notable strengths. To the best of our knowl-
edge, this is the first study that evaluated such a broad group
of mental disorders among mothers of preterm children. A
number of methodologic factors were used to minimize
bias and confounding, including: use of a large population-
based cohort, use of stringent inclusion and exclusion crite-
ria, use of matching and numerous covariates in regression
modeling, exclusion of mothers who delivered triplets or
higher-order births, and exclusion of mothers who had mul-
tiple preterm babies within the 5-year follow-up period. Our
physician-identified diagnoses are more specific than
symptom-based scales for mental disorders used in previous
studies. Unlike most other studies, we were also able to look
at varying degrees of prematurity and its association with
mental health outcomes.
Our study has certain limitations. Mothers with mental
disorders, especially substance use disorders, may have
been undercounted as administrative data only captures
those who are diagnosed by a physician or nurse practitioner.
We were unable to delineate the effect of prematurity sepa-
rately for maternal depression and anxiety because of the
way ICD-9 outpatient physician visit codes are recorded in
the Repository. Posttraumatic stress disorder is an important
mental disorder among these mothers that we could not eval-
uate, for this reason.
To conclude, our population-based control study showed
that among mothers without previous mental disorders iden-
tified within the 5 years before birth, the rate of new mental
disorders is not different between mothers of preterm and
term children. There was a dose response relationship
between prematurity and any mental disorder, mood and
anxiety disorders, and substance use disorders. Our regres-
sion analysis showed that extreme prematurity (<28 weeks)
was associated with the outcome of any mental disorder.
The results of this research outline the relationship between
preterm birth and maternal mental vulnerability suggesting
clinicians be more cognizant, especially of those mothers
whose premature babies were born at less than 28 weeks.
This may warrant routine screening for mental disorders
and follow up among mothers of preterm babies born at
such an early gestation.
Acknowledgments
The authors acknowledge the Manitoba Centre for Health Policy for
use of data contained in the Manitoba Population Research Data
Repository under project #2020-017 (HIPC#2020/2021-76). The
results and conclusions are those of the authors and no official
endorsement by the Manitoba Centre for Health Policy, Manitoba
Health, or other data providers is intended or should be inferred.
Data used in this study are from the Manitoba Population
Research Data Repository housed at the Manitoba Centre for
Health Policy, University of Manitoba and were derived from data
provided by Manitoba Health and Senior Care, Winnipeg Regional
Health Authority, Department of Families, Healthy Child Manitoba
Office, Statistics Canada and Manitoba Education and Training.
We would like to acknowledge the Diabetes Education Resource
for Children and Adolescents (DERCA) for use of their Pediatric
Diabetes Database. We would like to acknowledge the contributions
of Monica Sirski, data analyst at MCHP, for helping with building the
study cohorts and performing the data analyses.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to
the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for
the research, authorship, and/or publication of this article: This work
was supported by the Manitoba Medical Service Foundation
(MMSF) grant (grant no: 8-2021-07) awarded to Deepak Louis in
2021.
ORCID iDs
Deepak Louis https://orcid.org/0000-0002-8535-4208
James M. Bolton https://orcid.org/0000-0001-6319-5181
Supplemental Material
Supplemental material for this article is available online.
References
1. Preterm live births in Canada, 2000 to 2013. https://www150.
statcan.gc.ca/n1/pub/82-625-x/2016001/article/14675-eng.htm
(Accessed July 31, 2020).
2. Lim G, Tracey J, Boom N, et al. CIHI survey: hospital costs for
preterm and small-for-gestational age babies in Canada.
Healthc Q. 2009;12(4):20‐24.
3. Synnes A, Luu TM, Moddemann D, et al. Determinants of
developmental outcomes in a very preterm Canadian cohort.
Arch Dis Child Fetal Neonatal Ed. 2017;102(3):F235–F234.
4. Farooqi A, Hagglof B, Sedin G, Gothefors L, Serenius F.
Chronic conditions, functional limitations, and special health
care needs in 10- to 12-year-old children born at 23 to 25
weeks’gestation in the 1990s: a Swedish national prospective
follow-up study. Pediatrics. 2006;118(5):e1466‐e1477.
5. Marlow N, Wolke D, Bracewell MA, Samara M, Group EPS.
Neurologic and developmental disability at six years of age
after extremely preterm birth. N Engl J Med. 2005;352(1):9‐19.
6. Johnson S, Hennessy E, Smith R, Trikic R, Wolke D, Marlow
N. Academic attainment and special educational needs in
extremely preterm children at 11 years of age: the EPICure
study. Arch Dis Child Fetal Neonatal Ed. 2009;94(4):F283‐
F289.
La Revue Canadienne de Psychiatrie 0(0) 7
7. Litt JS, Gerry Taylor H, Margevicius S, Schluchter M, Andreias
L, Hack M. Academic achievement of adolescents born with
extremely low birth weight. Acta Paediatr. 2012;101(12):
1240‐1245.
8. Miles MS, Holditch-Davis D. Parenting the prematurely born child:
pathways of influence. Semin Perinatol. 1997;21(3):254‐266.
9. Woodall A, Howard L, Morgan C. Barriers to participation in
mental health research: findings from the genetics and psycho-
sis (GAP) study. Int Rev Psychiatry. 2011;23(1):31‐40.
10. Thornicroft, G. Shunned: Discrimination against people with
mental illness. New York: Oxford University Press; 2006.
11. Brown S. Mental Health and Reporting Bias: Analysis of the
GHQ-12. IZA Discussion Paper No 11771. 2018.
12. Shean G, Baldwin G. Sensitivity and specificity of depression
questionnaires in a college-age sample. J Genet Psychol. 2008;
169(3):281‐288.
13. Smarr KL, Keefer AL. Measures of depression and depres-
sive symptoms: beck depression inventory-II (BDI-II),
center for epidemiologic studies depression scale (CES-D),
geriatric depression scale (GDS), hospital anxiety and
depression scale (HADS), and patient health questionnaire-9
(PHQ-9). Arthritis Care Res (Hoboken). 2011;63(Suppl 11):
S454‐S466.
14. Smith M, Lix LM, Azimaee M, et al. Assessing the quality of
administrative data for research: a framework from the
Manitoba centre for health policy. J Am Med Inform Assoc.
2018;25(3):224‐229.
15. Jutte DP, Brownell M, Roos NP, Schippers C, Boyce WT,
Syme SL. Rethinking what is important: biologic versus
social predictors of childhood health and educational outcomes.
Epidemiology. 2010;21(3):314‐323.
16. Jutte DP, Roos LL, Brownell MD. Administrative record
linkage as a tool for public health research. Annu Rev Public
Health. 2011;32:91‐108.
17. Marrie RA, Fisk JD, Yu BN, et al. Mental comorbidity and mul-
tiple sclerosis: validating administrative data to support
population-based surveillance. BMC Neurol. 2013;13(1):16.
18. Chartier, M, Bolton, J, & Mota, N, et al. Mental Illness
Among Adult Manitobans. Winnipeg, MB: Manitoba Centre
for Health Policy; 2018.
19. Chateau D, Metge C, Prior H, Soodeen RA. Learning from the
census: the socio-economic factor index (SEFI) and health out-
comes in Manitoba. Can J Public Health. 2012;103(8 Suppl 2):
S23‐S27.
20. Austin PC. Optimal caliper widths for propensity-score match-
ing when estimating differences in means and differences in
proportions in observational studies. Pharm Stat. 2011;10(2):
150‐161.
21. Woodward, M. Epidemiology: Study Design and Data
Analysis. Third Edition (3rd ed.). Boca Raton, FL: Chapman
and Hall/CRC; 2013.
22. Kramer MS, Platt RW, Wen SW, et al. A new and improved
population-based Canadian reference for birth weight for gesta-
tional age. Pediatrics. 2001;108(2):E35.
23. Meltzer-Brody S, Maegbaek ML, Medland SE, Miller WC,
Sullivan P, Munk-Olsen T. Obstetrical, pregnancy and socio-
economic predictors for new-onset severe postpartum psychiat-
ric disorders in primiparous women. Psychol Med. 2017;47(8):
1427‐1441.
24. Silverman ME, Reichenberg A, Savitz DA, et al. The risk
factors for postpartum depression: a population-based study.
Depress Anxiety. 2017;34(2):178‐187.
25. Youn H, Lee S, Han SW, et al. Obstetric risk factors for depres-
sion during the postpartum period in South Korea: a nationwide
study. J Psychosom Res. 2017;102:15‐20.
26. Koh YW, Chui CY, Tang CS, Lee AM. The prevalence and risk
factors of paternal depression from the antenatal to the postpar-
tum period and the relationships between antenatal and postpar-
tum depression among fathers in Hong Kong. Depress Res
Treat. 2014;2014:127632.
27. Andrade, C. Mean difference, standardized mean difference
(SMD), and their use in meta-analysis: as simple as it gets. J
Clin Psychiatry. 2020;81(5):e1-e4.
28. Menard S. Collinearity. Applied logistic regression analysis
second edition (quantitative applications in the social sciences).
California: Sage Publications, Inc; 2001:75‐78.
29. Benjamini Y, Hochberg Y. Controlling the false discovery rate:
a practical and powerful approach to multiple testing. J R Stat
Soc: Ser B (Methodol). 1995;57(1):289‐300.
30. Newson RB. Frequentist q-values for multiple-test procedures.
Stata J. 2010;10(4):568‐584.
31. Slomian J, Honvo G, Emonts P, Reginster JY, Bruyere O.
Consequences of maternal postpartum depression: a systematic
review of maternal and infant outcomes. Womens Health
(Lond). 2019;15:1745506519844044.
32. Johansson M, Benderix Y, Svensson I. Mothers’and fathers’
lived experiences of postpartum depression and parental stress
after childbirth: a qualitative study. Int J Qual Stud Health
Well-Being. 2020;15(1):1722564.
33. Ali E. Women’s experiences with postpartum anxiety disorders:
a narrative literature review. Int J Womens Health. 2018;10:
237‐249.
34. Cheng ER, Kotelchuck M, Gerstein ED, Taveras EM,
Poehlmann-Tynan J. Postnatal depressive symptoms among
mothers and fathers of infants born preterm: prevalence and
impacts on children’s early cognitive function. J Dev Behav
Pediatr. 2016;37(1):33‐42.
35. Idstad M, Ask H, Tambs K. Mental disorder and caregiver
burden in spouses: the nord-trondelag health study. BMC
Public Health. 2010;10(1):516.
36. Murray L, Hipwell A, Hooper R, Stein A, Cooper P. The cog-
nitive development of 5-year-old children of postnatally
depressed mothers. J Child Psychol Psychiatry. 1996;37(8):
927‐935.
37. Murray L, Sinclair D, Cooper P, Ducournau P, Turner P, Stein
A. The socioemotional development of 5-year-old children of
postnatally depressed mothers. J Child Psychol Psychiatry.
1999;40(8):1259‐1271.
8The Canadian Journal of Psychiatry
38. Treyvaud K, Anderson VA, Howard K, et al. Parenting beha-
vior is associated with the early neurobehavioral development
of very preterm children. Pediatrics. 2009;123(2):555‐561.
39. Woodward LJ, Bora S, Clark CA, et al. Very preterm birth:
maternal experiences of the neonatal intensive care environ-
ment. J Perinatol. 2014;34(7):555‐561.
40. Cruise SM, Layte R, Stevenson M, O’Reilly D. Prevalence and
factors associated with depression and depression-related health-
care access in mothers of 9-month-old infants in the republic of
Ireland. Epidemiol Psychiatr Sci. 2018;27(5):468‐478.
41. Pooler J, Perry DF, Ghandour RM. Prevalence and risk
factors for postpartum depressive symptoms among women
enrolled in WIC. Matern Child Health J. 2013;17(10):
1969‐1980.
42. McDonald SW, Benzies KM, Gallant JE, McNeil DA, Dolan
SM, Tough SC. A comparison between late preterm and term
infants on breastfeeding and maternal mental health. Matern
Child Health J. 2013;17(8):1468‐1477.
43. Singer LT, Fulton S, Kirchner HL, et al. Parenting very low
birth weight children at school age: maternal stress and
coping. J Pediatr. 2007;151(5):463‐469.
44. Taylor HG, Klein N, Minich NM, Hack M. Long-term family
outcomes for children with very low birth weights. Arch
Pediatr Adolesc Med. 2001;155(2):155‐161.
45. Roosa Tikkanen KF, Williams II RD, Abrams MK. Mental
health conditions and substance use: Comparing U.S. needs
and treatment capacity with those in other high-income coun-
tries. USA 2020.
46. Gheorghe M, Varin M, Wong SL, Baker M, Grywacheski V,
Orpana H. Symptoms of postpartum anxiety and depression
among women in Canada: findings from a national cross-
sectional survey. Can J Public Health. 2021;112(2):244‐252.
47. de Paula Eduardo JAF, de Rezende MG, Menezes PR, Del-Ben
CM. Preterm birth as a risk factor for postpartum depression: a
systematic review and meta-analysis. J Affect Disord.
2019;259:392‐403.
La Revue Canadienne de Psychiatrie 0(0) 9
