RESEA
RCH
ARTICL
E
A multidisciplinary
Prematurity
Research
Cohort
Study
Molly
J. Stout
1
, Jessica
Chubiz
2
, Nandini
Raghuraman
2
, Peinan
Zhao
2
, Methodius
G.
Tuuli
3
, Lihong
V.
Wang
4
, Alison
G.
Cahill
5
, Phillip
S.
Cuculich
6
, Yong
Wang
2
, Emily
S.
Jungheim
ID
7
, Erik
D.
Herzog
8
, Justin
Fay
ID
9
, Alan
L. Schwartz
10
, George
A.
Macones
5
,
Sarah
K.
England
ID
2
*
1
Department
of Obstetrics
and
Gynecolog
y, University
of Michigan,
Ann
Arbor,
Michigan,
United
States
of
America,
2
Department
of Obstetr
ics
and
Gynecology
, Washingto
n University
in St.
Louis,
St.
Louis,
Missouri,
United
States
of America,
3
Department
of Obstetric
s and
Gynecolo
gy,
Brown
University,
Providenc
e, Rhode
Island,
United
States
of America,
4
Department
of Medical
Engineeri
ng,
Californi
a
Institute
of Technolo
gy,
Pasadena,
Californi
a, United
States
of America,
5
Departmen
t of Women’s
Health,
University
of Texas
at Austin,
Austin,
Texas,
United
States
of America,
6
Department
of Interna
l Medicine,
Washingto
n Universit
y in St.
Louis,
St.
Louis,
Missouri,
United
States
of America,
7
Department
of Obstetr
ics
and
Gynecolo
gy,
Northwestern
University
, Chicago,
Illinois,
United
States
of America,
8
Department
of
Biology
, Washingto
n University
in St.
Louis,
St.
Louis,
Missouri,
United
States
of America,
9
Department
of
Biology
, University
of Roches
ter,
Rocheste
r, New
York,
United
States
of America,
10
Departme
nt of
Pediatrics
, Washingto
n University
in St.
Louis,
St.
Louis,
Missouri,
United
States
of America
*
englan
ds@wustl.e
du
Abstract
Background
Worldwide,
10%
of babies
are
born
preterm,
defined
as
a live
birth
before
37
weeks
of gesta-
tion.
Preterm
birth
is the
leading
cause
of neonatal
death,
and
survivors
face
lifelong
risks
of
adverse
outcomes.
New
approaches
with
large
sample
sizes
are
needed
to identify
strate-
gies
to predict
and
prevent
preterm
birth.
The
primary
aims
of the
Washington
University
Prematurity
Research
Cohort
Study
were
to conduct
three
prospective
projects
addressing
possible
causes
of preterm
birth
and
provide
data
and
samples
for
future
research.
Study
design
Pregnant
patients
were
recruited
into
the
cohort
between
January
2017
and
January
2020.
Consenting
patients
were
enrolled
into
the
study
before
20
weeks’
gestation
and
followed
through
delivery.
Participants
completed
demographic
and
lifestyle
surveys;
provided
maternal
blood,
placenta
samples,
and
cord
blood;
and
participated
in up
to three
projects
focused
on
underlying
physiology
of preterm
birth:
cervical
imaging
(Project
1),
circadian
rhythms
(Project
2),
and
uterine
magnetic
resonance
imaging
and
electromyometria
l imag-
ing
(Project
3).
Results
A total
of 1260
participants
were
enrolled
and
delivered
during
the
study
period.
Of
the
par-
ticipants,
706
(56%)
were
Black/African
American,
494
(39%)
were
nulliparous,
and
185
(15%)
had
a previous
preterm
birth.
Of
the
1260
participants,
1220
(97%)
delivered
a live
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OPEN
ACCESS
Citation:
Stout
MJ, Chubiz
J, Raghura
man N, Zhao
P, Tuuli
MG, Wang
LV, et al. (2022)
A
multidiscipli
nary Prematurity
Research
Cohort
Study.
PLoS
ONE 17(8):
e0272155.
https://doi.
org/
10.1371/
journal.pone.
0272155
Editor:
Prem
Singh
Shekhawat,
Metrohea
lth
Medical
Center,
UNITED
STATES
Received:
August
27, 2021
Accepted:
July 13, 2022
Published:
August
25, 2022
Peer Review
History:
PLOS
recognize
s the
benefits
of transpar
ency
in the peer review
process;
therefore,
we enable
the publication
of
all of the content
of peer review
and author
response
s alongside
final,
published
articles.
The
editorial
history
of this article
is available
here:
https://doi.o
rg/10.1371/jo
urnal.pone.0
272155
Copyright:
©
2022
Stout
et al. This is an open
access
article
distributed
under
the terms
of the
Creative
Commons
Attribution
License,
which
permits
unrestricte
d use, distribu
tion, and
reproduction
in any medium,
provided
the original
author
and source
are credited.
Data
Availabilit
y Statement:
The data are not
publicly
available
as the minimal
data set for this
study
on pregnant
participants
contains
identifying
patient-lev
el data which
cannot
be suitably
de-
identified
or aggregated.
Addition
ally, a subset
of
infant.
Of
the
1220
with
a live
birth,
163
(14.1%)
had
preterm
birth,
of which
74
(6.1%)
were
spontaneous
preterm
birth.
Of
the
1220
participants
with
a live
birth,
841
participated
in cer-
vical
imaging,
1047
contributed
data
and/or
samples
on
circadian
rhythms,
and
39
under-
went
uterine
magnetic
resonance
imaging.
Of
the
39,
25
underwent
electromyometria
l
imaging.
Conclusion
We
demonstrate
feasibility
of recruiting
and
retaining
a diverse
cohort
in a complex
prospec-
tive,
longitudinal
study
throughout
pregnancy.
The
extensive
clinical,
imaging,
survey,
and
biologic
data
obtained
will
be
used
to explore
cervical,
uterine,
and
endocrine
physiology
of
preterm
birth
and
can
be
used
to develop
novel
approaches
to predict
and
prevent
preterm
birth.
Introduction
Preterm
birth,
defined
as
delivery
before
37
weeks’
gestation,
affects
1 in
10
babies
worldwide
and
is the
leading
cause
of
infant
mortality
[1].
Neonates
who
survive
are
at
increased
risk
of
lifelong
adverse
health
outcomes
[2–4].
This
problem
is especially
notable
in
St.
Louis,
Mis-
souri,
USA,
where
13%
of
babies
are
born
preterm
and
racial
disparities
are
pronounced;
11%
of
white
women
and
over
17%
of
Black
women
deliver
preterm
[5].
Despite
decades
of
research,
we
have
limited
understanding
of
the
causes
of
preterm
birth
and
few
strategies
to
predict
or
prevent
this
adverse
pregnancy
outcome.
In
2013,
Lackritz
and
colleagues
argued
that
preventing
preterm
birth
would
require
rigor-
ous
research
to
identify
the
underlying
biological
and
social
determinants.
Additionally,
they
argued
for
development
of
new
tools
to
monitor
pregnancy
and
identify
those
at
highest
risk
of
preterm
birth
[6].
To
that
end,
we
formed
the
Washington
University
in
St.
Louis
Prematu-
rity
Research
Center
in
2014
with
funding
from
the
March
of
Dimes
Foundation,
St.
Louis
Children’s
Hospital,
Barnes-Jewish
Hospital,
and
Washington
University
in
St.
Louis.
The
Pre-
maturity
Research
Center
united
a multidisciplinary
group
of
investigators
including
obstetri-
cians,
engineers,
circadian
biologists,
and
cardiac
electrophysiologists
to
approach
preterm
birth
in
novel
ways.
The
three
primary
projects
of
the
Prematurity
Research
Center
focused
on
identifying
ana-
tomic,
physiologic,
and
behavioral
features
that
are
associated
with
and
can
be
used
to
predict
preterm
birth.
The
first
project,
Cervical
Imaging,
used
high-speed
functional
photoacoustic
endoscopy
to
quantify
anatomic
changes
during
cervical
remodeling
[7,
8].
The
second
proj-
ect,
Circadian
Rhythms,
used
actigraphy,
hormone
secretion
patterns,
and
surveys
to
deter-
mine
whether
disruption
in
circadian
rhythms
is a risk
factor
for
preterm
birth
[5].
The
third
project,
Uterine
Electrical
Activity,
developed
a novel
imaging
system
to
noninvasively
map
electrical
activity
of
the
uterus
during
labor
contractions
[9–12].
To
gather
data
for
these
projects,
we
initiated
the
Prematurity
Research
Cohort
Study
to
longitudinally
follow
over
1000
participants
from
early
in
pregnancy
through
delivery.
The
purpose
of
this
report
is to
describe
the
demographics
of
this
cohort
and
the
types
of
data
and
biospecimens
obtained.
In
addition,
we
address
the
feasibility
of
conducting
a multidisciplin-
ary
study
in
which
a diverse
cohort
of
pregnant
patients
are
followed
throughout
pregnancy.
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participants
did not consent
for future
research
in
the patient
consent
form
approved
by the
Institutio
nal Review
Board
at Washingto
n
University
in St. Louis.
Proposals
for access
to this
data should
be directed
to christinek
ramer@wu
stl.
edu, Senior
Clinical
Researc
h Coordinat
or in the
Division
of Clinical
Research
in the Department
of
Obstetrics
and Gynecology.
To gain access,
data
requestors
will need
to sign a data access
agreement
.
Funding:
This work
was supported
by a research
grant
from
the March
of Dimes
Foundation
(to M.J.
S, P.Z, M.G.T.,
L.V.W.,
A.G.C,
Y.W.,
E.S.J.,
E.D.H.,
J.F, A.L.S.,
G.A.M.
and S.K.E.).
The cohort
was
make
possible
by support
institutio
nal support
from
St. Louis
Children
’s Hospital,
Barnes-J
ewish
Hospital,
and Washingto
n University
School
of
Medicine.
Competing
interests
:
The authors
have declared
that no competing
interests
exist.
Methods
The
Prematurity
Research
Cohort
Study
was
a prospective,
longitudinal
cohort
study
per-
formed
at
Washington
University
in
St.
Louis
Medical
Center
between
January
2017
and
Janu-
ary
2020.
A convenience
sample
size
of
1000
participants
was
chosen
as
a balance
between
an
aggressive
enrollment
target
given
annual
delivery
volumes,
the
need
to
recruit
and
retain
par-
ticipants
in
multiple
projects,
and
the
varied
outcomes
assessed
in
each
project.
No
a priori
power
analysis
was
conducted.
Participants
were
enrolled
in
the
first
or
early
second
trimester
and
followed
through
delivery.
The
study
received
ethical
approval
from
the
Washington
Uni-
versity
in
St.
Louis
Institutional
Review
Board.
All
participants
provided
written
informed
consent
for
collection
and
use
of
clinical,
biospecimen,
imaging,
or
questionnaire
data.
Inclusion
and
exclusion
criteria
Women
were
approached
for
enrollment
if they
had
a singleton
pregnancy
�
20
weeks’
gesta-
tion
(determined
by
best
obstetric
estimate
including
last
menstrual
period
or
earliest
ultra-
sound
dating
available)
and
met
the
following
inclusion
criteria:
plan
to
deliver
at
Barnes-
Jewish
Hospital,
18
years
of
age
or
older,
and
English
speaking.
Patients
were
not
eligible
if
they
were
incarcerated
or
conceived
via
in vitro
fertilization.
If a major
fetal
anomaly
was
diag-
nosed
during
pregnancy,
it was
reviewed
by
a maternal-fetal
medicine
attending
physician.
If
the
anomaly
affected
gestational
age
at
delivery,
the
patient
was
withdrawn
from
the
study.
Research
staff
A large
research
staff
was
assembled
to
support
all
projects
by
enrolling
participants,
perform-
ing
longitudinal
follow-up,
scheduling
appointments,
coordinating
research
study
visits,
con-
tacting
study
participants
who
missed
study
visits,
collecting
data,
and
managing
specimen
collection.
The
research
staff
comprised
one
research
coordinator,
three
registered
nurses,
one
sonographer,
three
research
associates,
a research
lab
coordinator,
and
one
research
lab
assis-
tant.
Additionally,
eight
staff
members
worked
exclusively
on
the
Labor
and
Delivery
floor
to
support
specimen
collection
and
data
acquisition
at
delivery
for
multiple
studies.
This
team
was
available
24
hours
a day,
seven
days
a week,
365
days
a year,
and
each
spent
approximately
25%
of
their
effort
on
the
three
Prematurity
Research
Center
projects.
In
addition,
two
statisti-
cians
provided
analytic
support,
and
a scientific
editor
reviewed
all
scientific
presentations
and
reports.
Participant
recruitment
and
longitudinal
follow-up
Patients
were
approached
for
enrollment
at
their
initial
prenatal
appointment
at
two
obstetric
clinics
on
the
Washington
University
Medical
Campus.
One
clinic
primarily
serves
patients
with
public
health
insurance,
and
the
other
primarily
serves
patients
with
private
health
insur-
ance.
All
potential
participants
were
offered
enrollment
into
projects
1 and
2.
Participants
were
seen
at
study
visits
longitudinally
throughout
pregnancy
and
at
delivery.
Study
visits
were
scheduled
to
obtain
data
and
samples
in
each
of
the
three
trimesters
(Fig
1)
.
All
study
visits
were
aligned
as
much
as
possible
with
routine
obstetric
care
to
minimize
inconvenience
to
the
participants.
When
additional
visits
were
needed
outside
of
routine
medical
care
visits,
appointments
were
scheduled
during
routine
business
hours
at
the
participant’s
convenience.
For
follow-up
and
retention,
participants
were
contacted
by
phone
and/or
text
messages
to
remind
them
of
study
visits,
and
transportation
was
arranged,
if needed,
to
facilitate
study
par-
ticipation.
Study
personnel
were
available
via
phone
and
text
during
business
hours
to
answer
study-related
questions.
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Data
and
specimen
collection
The
timing
and
sources
of
data
and
specimens
collected
are
illustrated
in
Fig
1
.
Case
report
form.
A comprehensive
case
report
form
was
used
to
collect
data
from
elec-
tronic
medical
records
on
the
index
pregnancy,
previous
pregnancies,
maternal
demographics
and
medical
history,
labor
and
delivery,
neonatal
outcomes
until
discharge
from
hospital,
and
maternal
postpartum
visits.
Obstetric
research
personnel
including
research
coordinators
and
research
nurses
were
trained
by
a Research
Nurse
coordinator
on
abstracting
clinical
data.
For
quality
assurance,
the
Research
Nurse
coordinator
performed
checks
on
these
data.
In
cases
in
which
the
participant
delivered
at
an
outside
institution,
medical
record
releases
were
requested
to
obtain
delivery
data.
The
case
report
form
used
to
collect
pregnancy
outcome
data
is shown
in
Table
1
.
Project
1—Cervical
imaging.
A research
nurse
collected
swabs
from
three
areas
of
the
vagina
(posterior
fornix,
mid-vagina,
and
introitus)
via
speculum
exam
immediately
before
performing
cervical
imaging.
Swabs
were
refrigerated
at
4 ̊C
immediately
after
collection
and
transferred
to
-80 ̊C
within
8 hours.
After
swab
collection,
novel
cervical
photoendoscopy
devices
were
used
to
obtain
cervical
imaging
data
transvaginally
[7,
8].
Additionally,
standard
transvaginal
ultrasound
images
of
the
cervix
were
obtained
and
used
to
measure
cervical
length
at
each
imaging
session.
Vaginal
swabs
were
collected
and
cervical
imaging
was
per-
formed
once
in
each
trimester.
A subset
of
participants
underwent
sampling
and
imaging
up
to
three
additional
times,
with
a minimum
of
four
weeks
between
sampling/imaging
sessions.
Fig
1.
Timing
and
sources
of
data
and
specimens
collected
from
the
cohort.
https://do
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Project
2—Circadian
rhythms.
All
participants
completed
validated
questionnaires
about
sleep
habits
and
other
lifestyle
measures
(
Fig
1 and
S1
Table
).
Participants
were
given
the
option
of
completing
surveys
via
an
online
link
or
taking
the
questionnaires
home
and
returning
them
to
research
staff
at
their
next
obstetric
or
research
study
visit.
Research
staff
called
or
texted
participants
to
remind
them
to
bring
completed
surveys
to
subsequent
study
visits.
Patients
with
incomplete
third
trimester
surveys
were
offered
the
opportunity
to
com-
plete
the
surveys
on
an
iPad
during
admission
for
delivery.
Table
1.
Case
report
form
for
pregnan
cy
outcomes
.
Date
of
delivery
Time
of
delivery
Preterm
birth
(
<
37
weeks)
Spontane
ous
preterm
birth
If
spontaneo
us
preterm
birth,
presenta
tion
Preterm
premature
rupture
of
membra
nes
Dilation
Preterm
premature
rupture
of
membra
nes
+ dilation
Other
(specify
)
Unknown/n
ot
available
Tocolytic
medicatio
n during
pregnanc
y
None
Magnesi
um
Indocin
Terbutaline
Nifedipine
Multiple
Unknown/n
ot
available
Gestation
al
age
at
delivery
If
term
birth
(
�
37
weeks),
presentatio
n
Prematu
re
rupture
of
membran
es
Dilation
Prematu
re
rupture
of
membran
es
+ dilation
Induction
Other
(specify
)
Unknown/n
ot
available
Was
magnesium
sulfate
administe
red?
Clinical
chorioamn
ionitis
Intrapart
um
antibiotics
Preterm
premature
rupture
of
membra
nes
prophylaxis
Group
B streptococcu
s prophylaxis
Chorioam
nionitis
Other
Unknown/n
ot
available
Type
of
delivery
Spontaneo
us
vaginal
Operative
vaginal
C-section
Unknown/n
ot
available
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Participants
provided
salivary
samples
every
four
hours
during
one
24-hour
period
each
tri-
mester,
with
collection
starting
at
18:00
hours.
Participants
received
supplies
to
collect
saliva
(Salimetrics,
United
Kingdom)
at
home.
Research
staff
called
or
texted
participants
to
remind
them
of
instructions
for
collecting
saliva
and
to
bring
their
samples
to
their
next
visit.
Partici-
pants
were
instructed
to
place
samples
in
the
freezer
until
bringing
them
to
the
research
staff.
Once
received,
the
samples
were
timestamped,
stored
at
-80 ̊C,
and
processed
to
measure
mel-
atonin
and
cortisol
concentrations
by
ELISA
(Salimetrics
Melatonin
ELISA
kit
and
Salimetrics
Cortisol
ELISA
kit)
in
a research
laboratory.
Participants
wore
wrist
actigraphy
devices
(Motionwatch8,
CamNTech,
United
Kingdom)
for
two-week
time
periods
during
their
first,
second,
and
third
trimesters,
as
outlined
by
Mar-
tin-Fairey
et
al.
[5].
The
actigraphy
devices
captured
minute-level
movement
and
light
expo-
sure
and
remained
charged
for
approximately
90
days,
ensuring
continuous
data
collection.
Research
staff
called,
texted,
or
emailed
participants
to
remind
them
to
bring
the
devices
back
to
the
next
study
visit
after
the
two-week
data
capture
period,
or
they
arranged
a courier
ser-
vice
for
retrieval.
If the
device
was
not
returned,
self-addressed,
stamped
envelopes
were
mailed
to
participants’
addresses
with
a letter
requesting
return
of
the
device
and
offering
a
$20
gift
card
if they
did
so.
Project
3—Uterine
electrical
activity.
Patients
meeting
the
following
inclusion/exclusion
criteria
were
offered
enrollment
into
Project
3:
Pre-pregnancy
body
mass
index
<
40kgm
2
,
willing
and
able
to
come
to
all
MRI
study
appointments,
no
claustrophobia,
no
metal
implants
or
non-removable
body
piercings,
and
no
plans
for
scheduled
cesarean
delivery.
Sixty-three
participants
from
the
total
cohort
were
enrolled
to
participate
in
Project
3.
Participants
included
those
at
low
risk
for
preterm
birth
(defined
as
a normal
cervical
length
at
anatomy
screen
and
no
history
of
spontaneous
preterm
birth)
and
those
at
high
risk
for
preterm
birth
(defined
as
a previous
spontaneous
preterm
birth
less
than
35
weeks
or
a cervical
length
less
than
2 cm
during
the
index
pregnancy).
Those
in
the
low-risk
group
underwent
uterine
mag-
netic
resonance
imaging
(MRI)
at
37
weeks’
gestation,
and
those
in
the
high-risk
group
under-
went
MRI
at
24,
28,
and
32
weeks
gestation.
Once
patients
presented
for
induction
or
in
spontaneous
labor
and
were
in
active
labor
(defined
as
greater
than
4 cm
dilation
and
regular
contractions),
body
surface
potential
mapping
was
performed
for
approximately
one
hour.
The
combined
uterine
MRI
and
body
surface
potential
mapping
resulted
in
data
used
for
elec-
tromyometrial
imaging
(EMMI),
which
has
been
described
elsewhere
[9–12].
MRI
was
per-
formed
in
a 3T
Siemens
Prisma/Vida
whole-body
MRI
Scanner
with
a radial
volume
interpolated
breath-hold
examination
fast
T1-weighted
sequence.
Patients
who
also
consented
to
be
a part
of
the
cervical
imaging
project
had
MRI
performed
on
the
same
day.
Biological
specimens
Maternal
blood
serum
and
plasma
samples
were
collected
throughout
pregnancy
during
rou-
tine
clinical
lab
visits
during
business
hours
(or
drawn
by
research
staff
if labs
were
done
else-
where
or
missed),
refrigerated
at
4 ̊C,
and
centrifuged
at
1620
x g for
5 minutes
at
4 ̊C
within
12
hours
of
collection.
Aliquots
(1
mL)
were
stored
at
-80 ̊C.
Cord
blood
serum
and
plasma
were
collected
at
delivery
and
processed
in
the
same
manner
as
the
maternal
blood.
In
cases
in
which
cord
blood
was
not
collected,
infant
buccal
swabs
were
collected
with
the
mother’s
con-
sent.
At
least
30
minutes
after
the
infant
was
fed,
a swab
was
rubbed
firmly
against
the
inside
cheek
and
lower
and
upper
lip
for
one
minute
and
stored
at
room
temperature.
Four
sets
of
placenta
specimens
(1x3
cm)
were
collected
at
delivery
from
each
of
four
sites:
chorionic
amnion,
basal
plate,
villous
tissue,
and
subchorion.
All
placental
samples
were
snap
frozen
in
liquid
nitrogen
and
stored
at
-80 ̊C.
Amniotic
fluid
was
collected
at
the
time
of
delivery
from
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56
patients
who
underwent
unlabored,
intact
cesarean
section.
Fluid
was
centrifuged
at
1620
x
g for
5 minutes
at
4 ̊C
and
then
stored
at
-80 ̊C.
Participant
incentives
All
participants
received
gift
cards
for
completing
study
visits.
Participants
received
$25
gift
cards
each
trimester
for
completing
the
combination
of
surveys,
wrist-worn
actigraphy,
and
24-hour
saliva
collection.
Participants
also
received
$25
gift
cards
for
each
completed
transva-
ginal
imaging
exam,
$50
gift
cards
for
each
MRI,
and
a $50
gift
card
at
delivery
if the
majority
of
study
procedures
were
completed.
Participants
also
received
a small
non-monetary
gift
(e.g.,
pen,
reusable
bag,
children’s
book)
at
the
completion
of
each
study
visit
and
at
delivery.
For
participants
without
reliable
transportation,
taxis
or
Uber
Health
cars
were
arranged
for
trans-
port
to
and
from
study
appointments
at
no
cost
to
the
participant.
For
prolonged
study
visits
that
spanned
a mealtime
(typically
3+
hours;
combining
clinical
appointment
with
transvagi-
nal
imaging
and
MRI),
a meal
was
provided
to
the
participant.
Granola
bars
and
other
small
snacks
were
available
to
participants
for
shorter
study
visits.
Crayons
and
coloring
pages
were
offered
to
the
children
of
participants
who
attended
study
visits.
Results
Participant
attrition
and
demographics
A flow
diagram
of
participant
enrollment
and
outcomes
is provided
in
Fig
2
.
We
screened
7478
patients
for
potential
enrollment;
2718
(36.3%)
met
inclusion
criteria
(
<
20
weeks’
gesta-
tion,
age
>
18
years,
English
speaking)
and
were
approached.
Among
those
approached,
1523
Fig
2.
Flow
diagram
of
participa
nt
enrollme
nt
and
outcomes.
cPAE
(cervical
photoacoust
ic endoscopy).
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.0272155.g00
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25,
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7 / 15
(56.0%)
gave
consent
and
enrolled.
Of
the
enrolled
participants,
190
(12.5%)
were
lost
to
fol-
low-up
and
73
(4.8%)
withdrew
and
were
not
included
in
the
final
analyses.
We
have
complete
clinical
and
outcome
data
on
1260
(82.7%)
participants.
Demographic
characteristics
of
the
1260
participants
are
described
in
Table
2
.
The
majority
of
participants
reported
being
employed
(70.8%),
Black/African
American
(56.0%),
and
single
(61.2%).
More
than
one-third
of
participants
(36.9%)
reported
an
annual
income
<
$25,000,
44.8%
had
public
insurance
or
were
uninsured,
and
53.9%
had
private
insurance.
Table
2.
Demograp
hic
data
of
study
participants
.
Total
enrolled
with
outcome
data
N
= 1260
Education
Less
than
12
th
grade
77
(6.1%)
High
school
degree/G
ED
583
(46.3%)
College
degree
(4
years)
179
(14.2%)
Gradu
ate
degree
250
(19.8%)
Missing/U
nknown
171
(13.6%)
Marital
status
Single
771
(61.2%)
Married
460
(36.5%)
Other
29
(2.3%)
Employme
nt
Yes
892
(70.8%)
No
273
(21.7%)
Student
39
(3.1%)
Missing/U
nknown
56
(4.4%)
Annual
income
(T1)
Govern
ment
Assistanc
e
92
(7.3%)
<
$25,00
0
465
(36.9%)
$25,000
-$74,999
265
(21.0%)
$75,000
-$124,999
155
(12.3%)
�
$125,0
00
160
(12.7%)
Missing/U
nknown
123
(12.7%)
Insurance
Medicai
d
410
(32.5%)
Medicare
21
(1.7%)
Individu
al/Group
Health
Insurance
679
(53.9%)
VA/Mi
litary
12
(1.0%)
Uninsured
134
(10.6%)
Missing/U
nknown
4 (0.3%)
Race
Black
or
African-Am
erican
706
(56.0%)
White
501
(39.8%)
Other
53
(4.2%)
Ethnicit
y
Non-H
ispanic
1213
(96.3%)
Hispanic
36
(2.9%)
Unknown
11
(0.9%)
English
first
language
1251
(99.3%)
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Pregnancy
characteristics
and
outcomes
Table
3
demonstrates
maternal
and
pregnancy
characteristics
in
our
cohort.
The
majority
(n
= 766,
60.8%)
were
multiparous,
and
185
(14.7%)
had
a history
of
preterm
birth.
The
most
common
medical
complications
among
these
participants
was
asthma
and
chronic
hyperten-
sion.
The
most
common
previous
pregnancy
complications
were
gestational
hypertension/
preeclampsia
and
intrauterine
growth
restriction
(
Table
3
).
In
the
cohort
of
1260
participants,
there
were
1220
(96.8%)
live
births,
23
stillbirths
�
20
weeks,
and
17
pregnancy
losses
<
20
weeks
(
Table
4)
.
Among
the
1220
participants
with
a live
birth,
529
(43.3%)
participants
underwent
induction
of
labor,
and
368
(30.2%)
were
delivered
via
cesarean
section.
Among
the
1220
participants
with
a live
birth,
1057
(86.6%)
delivered
at
term
and
163
(13.4%)
delivered
preterm
(
<
37
weeks).
Of
the
live-born
neonates,
145
(11.9%)
required
neonatal
intensive
care
unit
admission,
145
(11.9%)
had
low
birthweight
(
<
2500
g),
and
153
(13.1%)
were
small
for
gestational
age,
defined
as
birthweight
<
10
th
percentile
for
ges-
tational
age.
Data
and
specimen
collection
associated
with
study
procedures
Collectively,
study
participants
attended
6135
study
visits,
which
included
1892
cervical
imag-
ing
exams,
39
uterine
MRIs,
2239
actigraphy
recordings,
28,240
lifestyle
surveys,
and
over
12,000
biological
specimens
(see
Table
5
).
Fewer
participants
provided
saliva
samples
in
the
first
trimester
than
in
the
second
and
third
trimesters.
Conversely,
more
participants
com-
pleted
lifestyle
surveys
and
provided
actigraphy
data
in
the
first
trimester
than
in
the
second
Table
3.
Maternal
and
pregnancy
characterist
ics.
Gravidit
y
Gravida,
median
(IQR)
2 (1,4)
Parity
Nullipar
ous
494
(39.2%)
Multiparo
us
766
(60.8%)
History
of
preterm
birth
Indicated
10
(0.8%)
Spontan
eous
175
(13.9%)
24–33
6/7
weeks
107
(8.5%)
34–36
6/7
weeks
68
(5.4%)
History
of
pregnanc
y and
medical
complicat
ions
Asthma
248
(19.7%)
Gestatio
nal
hypertension/P
reeclamp
sia
214
(17.0%)
Chroni
c hyperten
sion
144
(11.4%)
Diabetes
71
(5.6%)
Intrauter
ine
growth
restriction
60
(4.8%)
Thyroid
disease
57
(4.5%)
Anomal
y
47
(3.7%)
Heart
disease
37
(2.9%)
Renal
disease
29
(2.3%)
Polyhydra
mnios
22
(1.7%)
Oligohy
dramnios
10
(0.8%)
Lupus
6 (0.5%)
Except
where
noted,
data
are
presented
as
n (%);
IQR,
interquar
tile
range
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Table
4.
Pregnancy
and
neonatal
outcomes.
Birth
outcome
Live
birth
1220
(96.8%)
Loss,
<
20
weeks
17
(1.3%)
Loss,
20+
weeks
23
(1.8%)
Gestation
al
age
at
birth
<
24
weeks
3 (0.2%)
24
weeks-31
weeks
6 days
32
(2.6%)
32
weeks-36
weeks
6 days
128
(10.5%)
37+
weeks
1057
(86.6%)
Preterm
Birth
Induced
89
(7.3%)
Spontan
eous
74
(6.8%)
x00A0
;
<
24
weeks
2 (.002%)
x00A0
; 24–33
weeks
6 days
22
(1.8%)
x00A0
; 34–36
weeks
6 days
50
(4.1%)
Deliver
y method
Vaginal
806
(66.0%)
Operati
ve
vaginal
46
(3.8%)
Cesarean
section
368
(30.2%)
Reason
for
induction
(N
= 529)
�
Oligohy
dramnios
6 (1.1%)
PROM
8 (1.5%)
PPROM
7 (1.3%)
Preecla
mpsia/eclamp
sia
59
(11.2%)
Comor
bidity
at
39
weeks
35
(6.6%)
Elective
236
(44.6%)
Non-rea
ssuring
antenatal
testing
40
(7.6%)
Gestatio
nal
Diabetes
16
(3.0%)
Postdate
s
64
(12.1%)
Intrauter
ine
growth
restriction
46
(8.7%)
Macrosomi
a
2 (0.4%)
polyhyd
ramnios
4 (0.8%)
Other
76
(14.4%)
Neonatal
Sex
Female
581
(47.6%)
Male
639
(52.4%)
Apgar
score
at
1 minute
0–3
59
(4.8%)
4–6
83
(6.8%)
7–10
1053
(86.3%)
Apgar
score
at
5 minutes
0–3
8 (0.7%)
4–6
40
(3.3%)
7–10
1163
(95.3%)
NICU
informat
ion
NICU
admission
145
(11.9%)
Length
of
NICU
stay
in
days
8 (4,
21)
Neonatal
health
outcomes
(
Continued
)
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/ 15
and
third
trimesters.
More
patients
underwent
transvaginal
imaging,
which
required
addi-
tional
scheduling
after
consent,
in
the
first
trimester
than
in
the
second
and
third
trimesters.
A total
of
63
participants
provided
consent
to
undergo
uterine
MRI
and
electrical
mapping
of
the
uterus
(electromyometrial
imaging
[EMMI])
at
labor
(
Table
6
).
A total
of
24
(17
low-
risk,
7 high-risk)
participants
withdrew
before
the
MRI
for
reasons
such
as
delivery
before
MRI
(8),
lost
contact
(6),
and
patient/family
request
to
withdraw
(6)
(
Table
6
).
A total
of
25
participants
in
the
low-risk
group
and
14
in
the
high-risk
group
underwent
MRI
at
least
once
during
pregnancy
(
Table
7
).
In
addition,
20
participants
in
the
low-risk
group
and
5 in
the
Table
4.
(Continu
ed
)
Low
birth
weight
(
<
2500
grams)
145
(11.9%)
Small,
for
gestati
onal
age
(
<
10
th
percentile)
153
(13.1%)
Arterial
umbilical
cord
pH
7.26
(7.22,
7.31)
Newborn
death
within
28
days
8 (0.7%)
�
The
percen
tage
of
reason
for
inductio
n is calculated
according
to
the
total
number
of
inducti
ons.
Some
participants
had
more
than
one
reason
for
inducti
on.
Data
represent
n (%)
or
median
(interquartil
e range).
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Table
5.
Sample
and
survey
number
s from
participants
with
live
births.
Samples
and
Data
Collected
First
Study
Visit
Second
Study
Visit
Third
Study
Visit
Delivery
Biologic
Samples
Maternal
blood
795
855
864
1023
Saliva
453
822
778
-
Vaginal
swabs
212
791
588
-
Maternal
buffy
coat
790
855
863
430
Placenta
-
-
-
1047
Cord
blood
-
-
-
870
Cord
blood
buffy
-
-
-
864
Amnioti
c fluid
-
-
-
56
Infant
buccal
swab
-
-
-
211
Cervical
Imaging
673
629
590
n/a
Actigraph
y
737
806
696
n/a
Surveys
Perceived
Stress
Scale
1136
786
825
n/a
Munich
Chronoty
pe
Question
naire
1047
784
823
n/a
Pittsburgh
Sleep
Quality
Index
1039
783
822
n/a
Berlin
Questionn
aire
984
781
823
n/a
Women
’s Health
Initiative
Insom
nia
Rating
Scale
983
782
821
n/a
Epworth
Sleepin
ess
Scale
1035
783
821
n/a
Intern.
Restless
Legs
1032
783
821
n/a
Kaiser
Physical
Activity
1030
781
821
n/a
Edinburgh
Postnatal
Depression
1212
874
866
n/a
Demograp
hic/Med.
Hist.
1111
801
845
n/a
Difficult
Life
Circums
tances
n/a
n/a
n/a
654
NIH
Diet
Questionnai
re
n/a
n/a
n/a
751
A total
of
1220
participants
had
live
births.
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high-risk
group
underwent
EMMI
at
labor
(
Tables
6 and
7
).
Reasons
for
missed
EMMI
included:
not
notified
by
Labor
and
Delivery
staff
(3),
delivered
at
offsite
hospital
(3),
COVID-
19
research
shut-down
(2),
and
emergent
cesarean
section
(2).
Among
those
who
underwent
both
MRI
and
EMMI,
none
of
the
low-risk
participants
and
two
of
the
high-risk
participants
delivered
preterm
(
Table
6
).
Discussion
The
Prematurity
Research
Cohort
Study
was
a multi-faceted
study
aimed
at
identifying
mech-
anisms
underlying
preterm
birth.
This
report
demonstrates
the
feasibility
of
conducting
a lon-
gitudinal
study
in
pregnant
participants
and
maintaining
high
consent
and
retention
rates.
Moreover,
we
describe
the
rich
data
and
specimen
source
now
available
for
longitudinal
stud-
ies
of
pregnancy.
The
primary
intent
of
establishing
this
cohort
was
to
identify
causes
of,
and
develop
novel
diagnostics
to
predict,
preterm
birth.
Analyses
of
data
from
surveys,
swabs,
specimens,
and
imaging
are
ongoing
for
the
three
projects.
Specimens
are
also
banked
for
future
research
to
identify
both
risk
factors
and
potential
biomarkers.
The
data
and
specimens
we
collected
will
be
useful
for
addressing
maternal
and
neonatal
health
disparities.
This
is because
over
50%
of
the
participants
were
Black,
and
all
lived
in
the
St.
Louis,
Missouri,
area,
where
Black
women
have
a 50%
higher
risk
of
preterm
birth
than
white
women
[5].
Feasibility
Within
three
years,
we
enrolled
1260
participants,
and
we
performed
6135
study
visits
span-
ning
all
trimesters.
Notably,
977
women
attended
three
or
more
visits
over
the
course
of
Table
6.
Project
3 participants.
Cohort
Consented
Withdrew
Reasons
for
Withdraw
al
Underw
ent
MRI
Missed
EMMI
Reasons
for
Missed
EMMI
Underwent
MRI
and
EMMI
Low
Risk
42
17
Delivered
before
MRI
(7)
Per
request
(5)
Lost
contact
(4)
Medical
issue
(1)
25
5
Missed
by
L&D
staff
(3)
Delivere
d precipito
usly
(2)
20
(0
preterm,
20
term)
High
Risk
21
7
Lost
contact
(2)
Delivered
before
MRI
(1)
Lethal
anomaly
(1)
Spontaneou
s abortion
(1)
Per
request
(1)
Social
issues
(1)
14
9
Delivere
d at
offsite
hospital
(3)
COVID
(2)
Emergen
cy
cesarean
(2)
Intrauter
ine
Fetal
Demise
(1)
Delivere
d precipito
usly
(1)
5 (2
preterm,
3 term)
EMMI,
electromy
ometrial
imaging;
L&D,
Labor
and
Delivery;
MRI,
magnetic
resonan
ce
imaging
https://do
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ournal.pone
.0272155.t006
Table
7.
Project
3 procedures
performed.
Group
and
procedure
Timing
24
weeks
28
weeks
32
weeks
37
weeks
Labor
Low
Risk—Uterin
e MRI
-
-
-
25
High
Risk—Ut
erine
MRI
14
9
9
-
Low
Risk—EMMI
-
-
-
-
20
High
Risk—E
MMI
-
-
-
-
5
EMMI,
electromy
ometrial
imaging;
MRI,
magnetic
resonance
imaging
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ournal.pone
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pregnancy.
We
collected
over
12,000
biological
specimens
with
linked
clinical
and
imaging
data.
Among
the
1260
enrolled
participants,
859
(68.1%)
participated
in
Project
1,
Project
2,
or
both,
the
two
projects
open
to
all
participants.
Study
participants
were
more
likely
to
comply
with
study
procedures
that
could
be
timed
with
clinical
appointments
or
labs
(e.g.,
blood
draws,
surveys
done
in
waiting
room
or
exam
room).
Fewer
data
and
specimens
were
collected
in
the
third
trimester
than
in
the
first
and
sec-
ond
trimesters.
In
part,
this
was
because
some
participants
delivered
before
their
third
trimes-
ter
study
visit.
Scientific
implications
The
Prematurity
Research
Cohort
Study
has
generated
a rich
set
of
data
and
specimens
that
can
be
used
to
test
hypotheses
pertaining
to
mechanisms
of
preterm
birth
and
preventive
tar-
gets.
This
dataset
and
specimen
bank
will
also
allow
investigators
to
explore
new
questions
regarding
preterm
birth,
use
imaging
and
biomarkers
to
assess
preterm
birth
risk
in
the
first
trimester,
and
identify
modifiable
lifestyle
factors
that
increase
risk
of
preterm
birth
[6].
Our
cohort
was
predominantly
those
with
the
highest
risk
of
preterm
birth:
women
of
color
and
women
with
socioeconomic
stressors.
Our
cohort
had
a higher
percentage
of
African
Ameri-
cans
(56%)
than
the
percentage
in
the
US
population
(13.4%)
and
had
high
rates
of
several
chronic
conditions,
which
likely
reflects
the
fact
that
the
study
was
conducted
at
a tertiary
care
hospital.
Our
experience
reveals
that
pregnant
patients
are
willing
to
participate
in
studies
that
require
multiple
research
visits,
undergo
serial
transvaginal
ultrasounds
or
MRI,
answer
exten-
sive
surveys,
wear
actigraphy
monitors,
and
collect
timed
saliva
samples
and
other
biological
specimens
beyond
those
required
for
routine
clinical
care.
Thus,
other
researchers
should
rec-
ognize
that
pregnant
patients
both
can
and
should
be
included
in
studies
for
obstetric
and
non-obstetric
outcomes.
Cost
and
resource
utilization
Conducting
this
study
required
extensive
investments
of
time
and
financial
resources.
Full
or
partial
salaries
were
required
for
the
80
staff
members,
31
trainees,
and
23
faculty
members
who
participated
in
various
aspects
of
the
study.
In
addition,
the
study
required
abundant
sup-
plies
(e.g.,
blood
and
placenta
sample
collection
tubes),
dedicated
freezer
space,
gift
cards,
and
transportation
arrangements.
Such
costs
and
resources
are
important
to
consider
in
planning
any
longitudinal
study
in
pregnancy.
To
reduce
costs,
future
studies
could
maximize
use
of
web-based
and
social
media
tools
to
optimize
recruitment
and
retention
[13,
14].
Although
we
did
not
formally
assess
patient-reported
acceptability
of
participating
in
the
cohort
study,
future
work
should
investigate
barriers
and
facilitators
to
patient
adherence
to
multiple
research
visits
during
pregnancy.
In
summary,
we
report
successful
enrollment
and
follow-up
of
a large
longitudinal
cohort
of
pregnant
patients.
Additionally,
we
describe
the
substantial
investments
made
by
partici-
pants
and
research
personnel
to
collect
data
and
specimens.
We
are
optimistic
that
their
con-
tributions
will
lead
to
new
discoveries
to
improve
the
health
of
pregnant
patients
and
their
babies.
Supporting
information
S1
Table.
Sleep
and
lifestyle
data
surveys
collected
from
participants.
(DOCX)
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S1
File.
(DOC)
Acknowledgmen
ts
We
thank
the
Prematurity
Research
Cohort
Study
participants
for
their
invaluable
contribu-
tions
to
preterm
birth
research.
We
thank
the
research
staff
for
their
tireless
efforts
enrolling
and
following
participants
and
collecting
and
managing
data
and
specimens.
We
thank
Debo-
rah
Frank,
PhD,
Stephanie
Pizzella,
Christine
Kramer,
and
Jillian
Ashley-Martin,
PhD,
for
edi-
torial
comments
and
Anthony
Bartley
for
graphical
assistance.
Author
Contributions
Conceptualization:
Peinan
Zhao,
Methodius
G.
Tuuli,
Lihong
V.
Wang,
Alison
G.
Cahill,
Emily
S.
Jungheim,
Erik
D.
Herzog,
Justin
Fay,
Alan
L.
Schwartz,
George
A.
Macones,
Sarah
K.
England.
Data
curation:
Peinan
Zhao.
Formal
analysis:
Molly
J. Stout,
Nandini
Raghuraman,
Peinan
Zhao,
Sarah
K.
England.
Funding
acquisition:
Methodius
G.
Tuuli,
Lihong
V.
Wang,
Alison
G.
Cahill,
Phillip
S.
Cucu-
lich,
Yong
Wang,
Emily
S.
Jungheim,
Erik
D.
Herzog,
Justin
Fay,
Alan
L.
Schwartz,
George
A.
Macones,
Sarah
K.
England.
Investigation:
Molly
J. Stout,
Methodius
G.
Tuuli,
Phillip
S.
Cuculich,
Emily
S.
Jungheim,
Erik
D.
Herzog,
Justin
Fay,
Sarah
K.
England.
Methodology:
Molly
J. Stout,
Jessica
Chubiz,
Methodius
G.
Tuuli,
Lihong
V.
Wang,
Alison
G.
Cahill,
Yong
Wang,
Emily
S.
Jungheim,
Erik
D.
Herzog,
Justin
Fay,
George
A.
Macones,
Sarah
K.
England.
Project
administration:
Molly
J. Stout,
Jessica
Chubiz,
Methodius
G.
Tuuli,
Lihong
V.
Wang,
Alison
G.
Cahill,
Yong
Wang,
Erik
D.
Herzog,
Justin
Fay,
Sarah
K.
England.
Supervision:
George
A.
Macones.
Writing
– original
draft:
Molly
J. Stout,
Jessica
Chubiz,
Nandini
Raghuraman,
Sarah
K.
England.
Writing
– review
&
editing:
Molly
J. Stout,
Jessica
Chubiz,
Nandini
Raghuraman,
Peinan
Zhao,
Lihong
V.
Wang,
Alison
G.
Cahill,
Emily
S.
Jungheim,
Erik
D.
Herzog,
Justin
Fay,
Alan
L.
Schwartz,
George
A.
Macones,
Sarah
K.
England.
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